Geothermal power plants produce a large volume of brine for power generation. Since these brines are the product of long-term water-rock interactions at elevated temperatures at depth, they contain dissolved chemical components including critical and strategic mineral commodities at various concentrations. Despite the low concentrations for many of these minerals, significant quantities of select minerals could be recovered due to the large volumes of brine utilized by geothermal power plants. Over the years, the U.S. Department of Energy (DOE) Geothermal Technologies Office (GTO) has been funding research activities focusing on characterization of brine resources and development of extraction technologies for the rare earth elements, lithium, and other critical minerals from geothermal brines. The primary goal of the GTO’s efforts is to secure domestic sources for these critical materials as well as provide an additional revenue stream to the geothermal developers and make geothermal energy more competitive against other types of renewable energy.

Our assessment of the US geothermal brines for their mineral contents indicates that several mineral commodities (e.g., Li, Mn, SiO₂, etc.) are present in high enough concentrations and sufficient flow rates to be economically recovered from geothermal brines. In this presentation, we will provide a summary for mineral contents in geothermal brines in the US. Also we will provide a summary of past as well as current mineral extraction status, opportunities, and challenges for the commercial-scale deployment of mineral extraction technologies.

Geothermal brines may contain a plenty of chemical elements in a wider range of concentrations ranging from trace to bulk concentration level. This makes such brines interesting for the winning of metals as well as of bulk chemicals. Main constraints are the high temperatures and pressures that should be maintained during processing, the accompanying gases like Methane and/or Hydrogen Sulfide and the enrichment of naturally occuring radionuclides during processing.

This can make such processes troublesome.

Coming from research in radioactive scales abatement a process and a galvanic high pressure cell were devoloped for electrochemical separation of valuable trace metals like Sb, Tl, Te from geothermal brine and testes over a longer period at our test facility at Neustadt-Glewe, Northern Germany. We also examined the extraction of numerous metals from brine sample from the Großschönebeck geothermal site by means of electrochemical and selective adsorption methods. In Addition based on brines from the Stassfurt geological series the winning of base chemical like hydrochloric acis and sodium hydroxide solutions was also shown to be possible by means of electromembrane processes. The economic potential of such methods will bei evaluated based on experimental data.

In order to increase the economic potential of geothermal power plants in view of environmental protection and sustainability, there are considerations to extract critical raw materials (CRM), such as lithium, from the geothermal fluids. The Upper Rhine Graben (URG) in southern Germany is of particular interest as it represents a hydrothermal fluid reservoir with large CRM potential.

Apart from the sedimentary strata with different reservoir rocks and associated fluids, their Variscan basement is exhumed in the Vosges and the Schwarzwald. Unconformity related hydrothermal vein-type and Mississippi-Valley-Type deposits evolved from paleofluids in the region. Recent fluids precipitate mineralogically and chemically similar scalings in the power plants indicating their potential for CRM extraction from these fluids. These access to all parts of a geological system in the URG area accounts for its consideration as a natural laboratory. Therefore, this study deals generally with metal provenance, reservoir processes, transport and precipitation mechanisms.

One of the hypotheses regarding those processes that lithium is released into the geothermal fluid by hydrothermal alteration of basement feldspars and mica. To corroborate the hypothesis, different reservoir rocks and fluids in various depths are mineralogically and geochemically investigated. The fluids analyzed to this point show different trace element distributions, which are associated with changes in Cl/Br and Rb/Cs ratios and might thus indicate an interaction of the fluids with the reservoir rocks. A comparison of modern fluid chemistry with the geochemistry of altered minerals, will help to link CRM provenance and content in modern fluids with economic potential.

Lithium is one of the critical elements for the realization of electric mobility and energy transition. With a contribution to global Li-production and recycling of less than 1% (2017), Europe depends almost entirely on Li-import. To reduce the dependency, new and unconventional Li resources are explored in the EU. One resource are highly saline brines from geothermal reservoirs of the Upper Rhine Graben (URG), characterized by Li concentrations of up to 200 mg/L. Due to space restrictions, conventional production methods are not suitable and technologies for the direct lithium extraction (DLE), such as Li-Mn oxide sorbents, is needed. Lithium-Mn oxide sorbents have a comparably high Li adsorption capacity and due to ion-sieve properties a high selectivity for Li. Batch experiments with synthetic Li⁺-solutions and natural geothermal brines were conducted to investigate the sorption capacity and kinetics, and the role of competing ions on Li sorption. The batch experiments reveal fast sorption kinetics with an adsorption of >70% of the maximum Li sorption capacity within several minutes. In relation to Li⁺-solutions, Li sorption decreases for geothermal brines due to sorption of competing ions. While alkaline metals show a relatively little influence, Mn and Ba are the major competing ions. We prove successfully that Li-extraction from geothermal brines in the URG by Li-Mn oxide sorbents is technologically feasible at the laboratory scale. Upscaling into a pilot plant integrated into a power plant is in progress.

The energy transition and the associated need for non-energy, mineral raw materials have prompted the German government to expand research and development activities along the entire value chain. It is well known that the highly mineralized thermal waters that circulate during the extraction of geothermal energy have, in some cases, significant enrichments of economically strategic elements such as lithium, rubidium, antimony or magnesium. The extraction of mineral resources from thermal waters is still challenging in terms of process technology, but new sustainable methods are paving the way for economic extraction as an alternative to conventional hard rock mining. Due to the overall high salt concentrations, selective separation of scale-forming minerals in a pretreatment stage is necessary to avoid scalings or membrane fouling in the later process steps.

The focus of this study is on controlling silicate precipitation, which is expected to occur due to temperature changes and proceeding concentration cycles, which are required for raw material and freshwater extraction. The treatment and an associated precipitation process must be cost-effective, integrable into the power plant process, and selective for silica but must not affect the concentration of valuable elements. In a multi-step and interdisciplinary process, a treatment strategy was developed and implemented in a large-scale prototype. In this study, the development of the silica processing strategy from laboratory to prototype design is described. Finally, the construction and implementation of a large-scale prototype with promising field results are presented.

Recently, the growing demand for carbon-free energy has sparked an unprecedented interest in naturally occurring H₂, as it could represent a potential alternative resource to fossil fuels. Throughout the world, and since more than one century, numerous natural H₂-bearing geological fluids have been discovered, but to date, there is neither exploration strategy nor any resource assessment, as practical guidelines for hydrogen targeting are still missing. Here, we lay the foundation of a preliminary exploration guide based on a global ‘source-transport-accumulation’ understanding of H₂-concentrating process and a combination of techniques and data used for both conventional petroleum and mining exploration. Based on different case studies, belonging to contrasted geological settings, we will provide the first elementary bricks to evaluate the sources, migration and trapping of H₂ in the Earth’s crust.

Water radiolysis is a key process for hydrogen (H₂) and abiotic organic molecules generation in the Earth’s crust. The aim of this presentation is to provide some insight into this process from a radiochemist viewpoint. We will transpose the knowledge we gain from water radiolysis in the context of radioactive waste disposal to natural geological settings and draw important conclusions for deep microbial ecosystems development and abiotic organic synthesis. Some examples will be given about: (i) the relationship between H₂ production ant the nature of the emitted particle (α/β/γ) considered for water radiolysis, (ii) the boosted production of H₂ observed when aqueous solutions are in contact with some mineral surfaces such as rutile (TiO₂) and calcite (CaCO₃), (iii) the scavenging role of carbonate anions onto hydroxyl radical and the amplified yield of H₂, (iv) the switch from an inorganic world to an organic one through the carboxylate anions production from carbonate radiolysis.

Radiation chemistry is often overlooked by geologists who consider the process as anecdotic (apart for the thermal budget of Earth) in term of mass balance. However, water radiolysis is a large-scale ubiquist process in the crust and it does not need specific conditions to occur. We will show that at geological time scale, water radiolysis leads to a very diverse, reactive, and fun chemistry able to sustain life and even to create the condition for its emergence.

Temporary underground storage of molecular hydrogen (H₂) in depleted oil and gas reservoirs has recently attracted increasing research interest as it can support chemical industry demands and peak-shaving in the energy supply grid. Experimental parameters related to abiotic chemical reactions, microbial metabolism, and transport mechanisms of molecular hydrogen under elevated pressure conditions in such reservoirs are of potential relevance to these applications but have rarely been studied. As far as abiotic chemical reactions are concerned, since mineral coatings of hematite are a common feature in conventional reservoirs, a thorough understanding of the reactivity of the hematite-H₂ reaction system is of utmost importance. In addition, potential microbial growth in the pore space of reservoirs may affect the preset gas composition as well as petrophysical properties.

In this context, RWTH-Aachen University is coordinating the “H2_ReacT2” project, a follow up cooperation together with the Bundesanstalt für Geologie und Rohstoffe (BGR) and the Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ). The overall objective is to gain a comprehensive understanding of relevant abiotic and biotic redox reactions, associated changes of petrophysical properties and molecular mass transfer within potential underground storage formations.

In this session, we will present analytical data of novel experimental approaches to study (1) the kinetics of the H₂-H₂O-hematite reaction system at low temperatures and elevated H₂ pressures, and (2) the effects of microbial metabolism of H₂ and overburden pressure on storage and transport properties of a typical reservoir rock, the Bentheimer sandstone.

Current renewable energies are unsteady resulting in temporary mismatches between demand and supply. The conversion of surplus energy to hydrogen and its storage in geological formations is one option to balance this energy gap. This study evaluates the feasibility of seasonal storage of hydrogen produced from excess wind power electricity in a saline aquifer in Castilla-León region (northern Spain). A 3D multiphase numerical model is performed to test different extraction well configurations during three annual injection-production cycles in a selected underground sandstone formation (Utrillas Fm) in the Duero basin. Results demonstrate that underground hydrogen storage in saline aquifers can be operated with reasonable recovery ratios. A maximum hydrogen recovery ratio of 78%, which represents a global energy efficiency of 30%, has been estimated. Hydrogen upconing emerges as the major risk on saline aquifer storage. However, shallow extraction wells can minimize its effects. Steeply dipping geological structures are key for an efficient hydrogen storage.

Recently, politics and industry has discussed green hydrogen as one of the carbon-zero energy sources of the future. Besides many other countries, Germany formulates clear goals for the energy transition from fossil to hydrogen energy in its "National Hydrogen Strategy". In order to ensure steady supply of hydrogen and to secure national reserves the underground storage of hydrogen (UHS) is increasingly coming into focus. Germany already has extensive experience in storing natural gas to cover supply shortages in the medium term, which follows same geologic principles as for hydrogen. In general, there are two main underground storage options for hydrogen. While in caverns such as salt-caverns operating UHS localities already exist, hydrogen storage facilities in porous media like aquifers or depleted gas reservoirs are still unrealized. In recent studies such as InSpEE and INSPEE-DS, the Federal Institute for Geoscience and Resources (BGR) provided a sound database of potential salt structures and salt horizons that could be used for UHS. This study gives an overview over the research made within all known types of underground hydrogen storage and discusses each their potential in Germany.

Cold and deep subduction is a characteristic feature of modern-style plate tectonics (MSPT) and a prerequisite for the formation of low-temperature/high-pressure (LT/HP) and ultrahigh-pressure (UHP) rocks. Although having strong implications for processes like the movement of materials between surface and mantle, mantle convection, thermal regimes, or the crustal growth rate, the onset of MSPT is poorly understood and controversially debated. One argument for an early onset are local occurrences of Paleoproterozoic retrogressed rocks suggested to have initially formed at LT/HP conditions (e.g., Weller & St-Onge, 2017, Nature Geoscience 10, 305-311). In contrast, a major argument for a late onset is the absence of mineralogical indicators for LT/HP and UHP metamorphism, like glaucophane and coesite, from the pre-Neoproterozoic crystalline rock record (e.g., Stern, 2005, Geology 33, 557-560). A limiting factor for the exploration of LT/HP and UHP rocks through time is the decreasing preservation of crystalline rocks with increasing age. Thus, the sedimentary record represents an important archive that preserves information on ancient continental crust lost due to erosion (e.g., Dhuime et al., 2017, Sedimentary Geology 357, 16-32). Nevertheless, reconstructing metamorphic conditions from a sedimentary perspective is challenging, mainly because we face sand-sized mineral grains that lost their paragenetic context. Here we present a selection of case studies that highlight the applicability of mineral inclusion assemblages in detrital garnet as an excellent petrogenetic indicator. This technique enables to partially reconstruct the paragenetic context and to screen the underexplored sedimentary record for mineralogical evidence supporting the operation of MSPT in deep time.

We present U-Pb, Lu-Hf, and O isotopic data, as well as size-shape data for approximately 3700 detrital zircons from 15 European rivers. In combination with geomorphological information for each river basin (area, drainage length, and hypsometric curves), we evaluate the representativeness and biases affecting such datasets. The new data allow us to demonstrate that the detrital zircon record from major rivers represents all relevant geological events in Europe at the continental scale, with detrital zircon ages ranging from Cenozoic to Archean. Several age peaks can be linked to different orogenic cycles and the formation of supercontinents such as Pangea and the Variscan Orogen, the largest episode of crustal reworking in Europe. These Variscan detrital zircons occur in all rivers, but Permian post-Variscan were only found in the Po (with significant crustal contamination) and Glomma rivers (with radiogenic and mantle-like signatures). Other important age clusters are the Alpine and post-Alpine Cenozoic 25-40 Ma and juvenile 0.2-10 Ma, the Caledonian 400-490 Ma, and the Avalonian-Cadomian 540-650 Ma. Detrital zircons of 930-1170 Ma and 1400-1700 Ma are significant in Scandinavia, as well as ca. 1850 and 2500-2900 Ma in east Europe. Despite the good representation of the different geological events in Europe, this does not occur when analyzing detrital zircon at smaller scales (i.e. the basin scale). The presence, importance, and proportions of peaks are strongly dominated by factors such as fertility, zircon-size-shape, and other geomorphological aspects. Excluding fertility, these factors alone can bias the proportion of peaks by up to 10%.

Detrital heavy mineral compositions are controlled by many factors such as mineral fertility in the source rocks and hydraulic sorting. Quantifying and understanding the resulting bias is crucial especially for the correct interpretation of single-grain analyses such as apatite or zircon geochronology in provenance studies.

In this study, an inter- and intrasample comparison of apatite and zircon concentrations is conducted on modern Alpine fluvial sands from five mono-lithological catchments draining granitoid, ophiolitic, metamorphic and sedimentary sources. The distribution of these minerals was quantified and compared within narrow grain size windows of each sample using point counting in strewn slides, XRF analysis of P₂O₅ and Zr as proxies for apatite and zircon, respectively and modelling based on the size shift. In addition, those results have been compared with other complementary monolitholigical catchments from the Alps.

While in line with published fertility values in the Alps, the apatite and zircon concentrations vary over three orders of magnitude. The intra-sample comparison shows highest zircon and apatite concentrations in the finer grain size fractions (63-250 µm), which is expected from the settling-equivalence principle. Furthermore, the apatite and zircon concentrations derived from point counting correlate well with those estimated from P₂O₅ and Zr concentrations through XRF analysis. However, the XRF analysis also reveals a significant amount of P₂O₅ and Zr contained in the grain sizes smaller than 63 µm. This is especially important, since many single-grain provenance studies do not consider the silt and clay fractions.

In-situ U-Pb-He double-dating of detrital zircon provides information regarding formation and cooling ages of source rocks. Its advantage over conventional dating methods is the unique ability to obtain a high quantity of precise single zircon data with constraints for both low- and high-temperature chronology. In provenance studies the information collected by double-dating can be used to reconstruct more complex tectonic settings and geologic evolution of individual zircons. Here, it is used to distinguish the components and tentative mixing ratios of sediments from multi-source catchments with the aim of assigning them to their respective sources.

The European Alps provide a great natural laboratory to test the capabilities of the method. Considering their well-studied and complex tectonic evolution, i.e. the combination of Proterozoic to Tertiary magmatism and high-grade metamorphism with spatially strongly contrasting Late Mesozoic to Neogene exhumation, none of the conventional chronological tools can draw a nearly as accurate picture.

Detrital zircons from modern river sands taken in the catchments of the Alpine Inn and its tributaries were dated: Ages derived from the Zillertal (dewatering mostly the Tauern window) and the Ötztal (incising the Austroalpine basement nappes) correspond to published data and can explain the complex age distribution of zircons collected near the end of the Alpine Inn. Double-dating is extraordinarily well suited to decipher such in-depth information, especially in complex orogens where different structural units experienced different overprinting of isotopic systems, leading to high spatial contrasts in low- and high-temperature chronological data.

Detrital zircon (DZ) U-Pb geochronology is widely applied in the geosciences to address a very wide range of questions. However, zircon is refractory and discrimination of first- versus multi-cycle origin is challenging which blurs source-to-sink relationships. We performed DZ U-Pb geochronology of modern sediments in fluvial and littoral environments on the Scott Coastal Plain in Western Australia. Principal age modes are at c. 730-500 Ma and c. 1100-880 Ma (Pinjarra Orogen), c. 1240-1120 Ma and c. 1700-1600 Ma (Albany-Fraser-Wilkes Orogen), and c. 2710-2580 Ma (Yilgarn Craton), corresponding to ultimate derivation from local crystalline basement rocks. The DZ U-Pb age spectra show a mismatch to the areal extent of source rocks in the catchment area. Here, we propose the application of a novel approach – source-normalized α-dose – to quantify active time of DZ grains in the sedimentary system and thus identify sedimentary recycling of DZ. This metric compares the α-dose (a measure of metamictization using U and Th content) of DZ and the values of crystals from their source crystalline basement. We show that source-normalized α-dose records the selective removal of labile (high α-dose) grains and is able to discriminate (i) first-cycle and (ii) multi-cycle DZ populations that experienced progressive sedimentary recycling and/or transport. Source-normalized α-dose provides an internal measure to address sedimentary recycling of DZ, i.e., it does not necessitate comparison with other mineral systems. Consequently, this tool aids in the identification of first- and multi-cycle DZ origin and ultimately strengthens source-to-sink correlations improving interpretation of DZ grain histories.

Carbonatites crystallize from mantle-derived carbonate- and volatile-rich melts that exsolve large amounts of fluids during their ascent through and emplacement into the crust. A global review of available fluid inclusion data for carbonatitic systems from variable emplacement depths identified four types of fluid inclusions: (type-I) vapour-poor H₂O-NaCl fluids with <50 wt.% salinity; (type-II) vapour-rich H₂O-NaCl-CO₂ fluids with <5 wt.% salinity; (type-III) multi-component fluids with high salinity without CO₂; and (type-IV) multi-component fluids with high salinity and high CO₂. This global data set indicates initial release of type-I saline brines that may either separate into immiscible type-II and -III fluids (eruption?) or may continuously evolve into type-IV fluids (sealing?). Moreover, fluid inclusions in early magmatic apatite crystallization suggest initial fluid release (type-I) at depths of 12-16 km (brittle-ductile transitions zone), which may be related to a sudden pressure drop initiated by crustal fracturing during rapid, forceful and discontinuous magma ascent.

Our model for the ascent of carbonatitic magmas is adopted from a jackhammer-like process, which explains the apparent absence of shallow carbonatite magma chambers, reflects the observed intrusion geometries, identifies fenitization as a process induced by fluids released during magma ascent and final emplacement, and demonstrates the formation of fluid induced brecciation related to magma ascent. The proposed model of a self-sustaining system is also in agreement with a turbulent ascent and high ascent rates, which allows for the transport of mantle xenoliths through the crust as observed in several cases.

The igneous nature of carbonatites has been controversial for decades until experimental work in the 1960s and 1970s conclusively showed that carbonatite melts can exist in geologically reasonable conditions. The observation of natrocarbonatite eruptions at Ol Doinyo Lengai further confirmed their igneous nature. However, these lines of evidence for igneous carbonatites have been a red herring: many ideas, processes, and terms deriving from silicate magma systems were inaccurately projected into carbonatite systems. Instead, carbonatites should be considered as hybrid metasomatic and magmatic cumulate rocks. The low viscosity and efficient wetting of carbonatite melts makes them behave more like hydrothermal fluids, preventing formation of magma chambers. Their high chemical reactivity and disequilibrium with their host rocks leads to rapid and substantial chemical exchange with their surroundings. Therefore, the chemical composition of their host rocks imparts a first order effect on the mineral assemblage observed in solidified carbonatite rocks. Rare earth elements are typically incompatible during carbonatite melt fractionation. Whether REE mineralisation is observed in Ca, Mg, or Fe-dominated mineral assemblages is strongly dependent on the degree and nature of silicate contamination. In special cases, REE can be highly compatible and mineralisation forms early rather than late. Enigmatic light REE mineralisations in fenite-like assemblages can likewise be explained as an end-member of carbonatite–rock interaction.

Carbonatites host the main REE deposits in the world, with bastnaesite being the main REE-bearing mineral of interest. However, the nature of the enrichment process, magmatic vs hydrothermal, is still debated. This study aims to experimentally determine the behaviour of REE elements during carbonatite crystallisation, and if bastnaesite can be directly crystallised from a carbonate melt.

Crystallisation experiments have been done from 900 to 600°C at 1 kbar on a REE-rich calciocarbonatitic composition. Calcite (Ca,REE)CO₃ is the dominant magmatic mineral, so the residual melt evolves toward natrocarbonatitic compositions as crystallisation proceeds. A small amount of britholite (REE,Ca)₅((Si,P)O₄)₃(OH,F) is observed at high temperatures and is replaced by phlogopite KMg₃(AlSi₃O₁₀)(OH)₂ and apatite (Ca,REE)₅(PO₄)₃(F,OH) at T < 650°C. A small amount of pyrochlore (Ca,Na,REE)₂Nb₂O₆(OH,F) is observed at T < 700°C.

No bastnaesite has been found in any crystallisation experiment. We thus performed a bastnaesite saturation experiment at 600°C. The melt saturated with bastnaesite however contains 20 wt% of REE: such high value implies that magmatic saturation of bastnaesite is unlikely to happen in nature.

F, Cl and water decrease the temperature of calcite saturation, allowing the system to crystallise at lower temperatures. REE are slightly incompatible with calcite, especially at low temperatures. The residual carbonate melt is thus enriched as crystallisation proceeds. Finally, we collected textural and chemical evidence suggesting the presence of a Na,Cl,REE-rich fluid at high temperatures and under hydrous conditions. Such Na,Cl,REE-rich fluids may play a critical role in the remobilisation of REE and the bastnaesite crystallisation during subsolidus reactions.

The Oulad Dlim massif in the southernmost part of Morocco hosts several carbonatite bodies of different ages. The older carbonatite (1.85 Ga) occurs in the eastern Oulad Dlim massif in the Gleibat Lafhouda area and consists of three juxtaposed magnesiocarbonatite outcrops. They are associated with glimmerite, hosted by Archean gneiss, and unusually intruded by massive IOA deposits. The latter contains up to several wt% REE related to numerous monazite-(Ce) inclusions within large apatite crystals. Columbite-(Fe) is the main Nb-mineral and occurs closely associated with Fe-phases, whereas microlite and Ta-rich columbite-(Fe) are mainly associated with coarse-grained apatites hosted by Fe-oxides and silica breccia. Geochemical characteristics and textural relationship suggest that they are genetically linked to the carbonatite and likely formed by late hydrothermal fluids at multiple stages. Small outcrops of nepheline syenite occur at several km from this carbonatite and might be genetically related. The youngest carbonatite (104 Ma) is a soevite and crops out within a ring structure composed of silica breccia and Fe-oxide mineralization at the Twihinat area of the western Oulad Dlim massif without visible associated alkaline rocks. All outcropping rocks at Twihinat show epigentic REE-Nb mineralization, mainly as bastnaesite within the carbonatite and silica breccia and monazite within the Fe-oxides. Pyrochlore senso-stricto occurs within the carbonatite, whereas cerio-pyrochlore is dominant in the silica breccia. The mineralogical and geochemical signatures of all Twihinat rocks suggest ore precipitation from multistage REE-Nb-rich hydrothermal fluids that percolated through the carbonatites and the associated rocks.

Contamination of carbonatite melts is often neglected due to a fast magma ascent and low liquidus temperatures. However, increased silicate mineral formation observed in numerous carbonatite occurrences world-wide requires an external Si introduction. Our study demonstrates that carbonatite dykes penetrating different lithologies of Palabora (South Africa) shows different modes of mineralogical modification. In particular Al and Si-rich lithologies show the most significant effects. Besides silicate mineral formation Si introduction may cause directly and indirectly variations of the REE mineralization at different stages of the carbonatite emplacement. While Si introduction during apatite formation causes an increased REE incorporation into apatite due to the britholite substitution accompanied by an early consumption of REE from the melt, an REE enrichment in the melt and related specific REE mineral formation in late magmatic stages become inhibited. A Ti-rich carbonatite magma additionally experiences the formation of titanite at the expense of ilmenite. Although REE consumption by titanite is less important as for apatite, specific REE consumption can influences REE patterns of subsequent mineralizations. On the other hand, magma wall rock interactions in a carbonatitic systems may furthermore directly influence the type of REE mineralization reflected by discrete REE minerals. In this way contamination can directly control the formation of either allanite, britholite, chevkenite or monazite and hence influences the economic processibility of a REE deposit. Furthermore, the stability of HFSE minerals such as baddeleyite or thorianite can be suppressed by the predominance of their Si-bearing counterparts (e.g., zircon and thorite).

Since 2012 many wind turbines have been installed on the Frankonian Jura and a number of them also in the vicinity of stations of the Gräfenberg array (GRF), consisting of 13 broadband stations within an area of about 50x100 km. It has been shown that these turbines take a significant effect on the noise level at many of the GRF station sites (Stammler & Ceranna, 2016, reference below). The array as a whole suffers from a deterioration of its sensitivity to teleseismic events of more than 0.1 magnitude units at wind speeds above 3.5 m/s (in 10m height). At individual station sites the noise signatures at frequencies above 2 Hz can be attributed to close-by wind turbines observing an approximate power decay law with increasing distance to the recording site. At a frequency of about 1.1 Hz, however, at most stations the strongest influence is visible, but the relation between measured PSD amplitudes and turbine distances does not support a simple decay law when taking into account only the closest wind turbine locations. This suggests that for this frequency turbines at larger distances play a role. This investigation tries to model the propagation of the turbine induced noise and to explain the observed PSD values at the GRF stations. As a result the contributing turbines can be identified as well as average propagation properties for the noise waves determined.

Influence of Wind Turbines on Seismic Records of the Gräfenberg Array, Klaus Stammler and Lars Ceranna, Seism.Res.Lett. (2016) 87(5): 1075-1081, https://doi.org/10.1785/0220160049

Seismologist noticed are worsening of station quality after the installation of wind turbines (WTs) close to seismological stations. Since WTs and seismological stations are installed mostly in areas with low population density, both are looking for solutions to diminish this conflict.

For this, we tested different denoising techniques at affected seismological stations to reduce or to eliminate the disturbing WT signal from the seismological data. Usually, spectral filtering is used to suppress noise in seismic data processing. However, this approach is not effective when noise and signal have overlapping frequency bands which is the case for WT noise. First, we applied a nonlinear thresholding function on our data. This method leads to good results when the event can be already seen in the raw data but it fails when the event is fully covered by noise. As a second method, we used a denoising autoencoder (DAE), which learns a sparse representation from time-frequency coefficients, and maps from there to output masking functions for signal and noise. The DAE is more time consuming in comparison to the nonlinear thresholding function but when the convolutional neural network is trained, using an adequate training dataset, it can also be applied instantly on the raw data. The DAE distinguishes between signal and noise and we are able to correct the seismograms from most of the disturbing noise signals.

Aerodynamic infrasonic signals generated by wind turbines can be detected by highly sensitive micro-barometers showing spectral peaks at the blade passing harmonics, which are above the background noise level. As infrasound is one of the four verification technologies for the compliances with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), decreases in detection capability for dedicated infrasound arrays have to be avoided. Therefore, preventing such decrease is particularly important for the two German infrasound stations IS26 in the Bavarian Forest and IS27 in Antarctica, which are both part of CTBT’s International Monitoring System and have to meet stringent specifications with respect to their infrasonic ambient (natural and anthropogenic) noise levels.

In 2004, micro-pressure variations along a profile starting at a single horizontal-axis wind turbine were measured during a field experiment with mobile micro-barometer stations. As one of the results, a minimum distance to wind turbines for undisturbed recording conditions at infrasound array IS26 was estimated based on numerical modelling, validated with this dataset. Both observations and modelling were in agreement with the literature, where infrasonic signatures of wind turbines are reported at distance ranges up of tens of kilometres. Nevertheless, for broadening the dataset further infrasound measurements at two wind parks with modern large wind turbines have recently been carried out in Lower Saxony and Saxony-Anhalt, respectively. Here various instruments (micro-barometers, microphones, pressure sensors) have been deployed in a comparative manner. We will give an overview of these campaigns, followed by first results of our analysis and interpretation.

Repeated seismic activity can cause progressive failure of rock masses due to material fatigue [1]. To simulate induced seismic loading, an iron ore with alternating quartz- and magnetite-rich layers from the Sydvaranger mine (Finnmark/Norway) was subjected to laboratory uniaxial compressional cyclic loading at low stresses in the range of elastic deformation (about 6 MPa static ±3 MPa dynamic pressure) and frequencies related to induced seismicity (10 – 100 Hz) [2]. Some of the experiments were performed until material failure occurred at up to 2 million cycles. Changes in magnetic behaviour were identified by measurements of magnetic susceptibility from Verwey transition in magnetite (about 120 K) to room temperature after intervals of 150 000 loading cycles. Magnetic domains were analysed with magnetic force microscopy. Deformation-related surface structures on magnetite and quartz were identified by reflected light microscopy and high-resolution scanning electron microscopy and compared to results from Raman spectroscopy.

Dynamic mechanical analysis (DMA) was used for cyclic loading, which is a common method for determination of viscoelastic behaviour, especially of soft materials with pronounced viscoelasticity like polymers. Suitability of DMA for determination of relative changes of viscoelastic parameters during cyclic loading will be discussed under consideration of the relatively high Young’s modulus and almost ideal elastic behaviour of the iron ore under the chosen experimental conditions.

[1] Gischig et al. (2016) Rock Mech Rock Eng, 49, 2457-2478.

[2] https://www.geosig.com (2009), Seismic Signals and Sensors.

Traffic light systems (TLSs) are used in different energy technologies for limiting the strength of induced seismicity. The TLS concept is based on real-time monitoring of induced seismicity in combination with operational mitigation measures that are triggered if the intensity of the seismicity exceeds certain threshold values. We use observations, conceptual and numerical models for investigating efficiency and limitations of TLSs. Most notably, TLS efficiency can be limited by trailing effects caused by post-injection pressure diffusion and stress concentrations at the periphery of previous seismic activity. The latter ‘stress memory’ can be the cause for seismicity occurring a long time after reservoir activities stopped. We speculate that a similar type of stress concentration could have been the nucleus of the M_w=5.5 earthquake at the Pohang geothermal site.

Wind turbines are massive tall buildings which swing considerably above the ground, especially when they are in operation. These oscillations are composed of the eigenmodes of the whole building and the interaction of the passing blades with the tower. The oscillations are transferred into the ground by interaction of the moving foundation with the ground (soil / rock). The radiated wavefield is composed of elastic waves, conformable to seismic waves. Mainly surface waves are excited whose amplitudes decay with distance due to the geometric amplitude decay, the anelastic damping and the wave scattering, depending on the elastic properties of the rock along the propagation path. The related ground shaking is hardly felt by humans, however, sensitive high-tech instruments (electron microprobes, seismometers etc.) can be disturbed even at long distances. Thus, the knowledge about the source and propagation properties is vital to predict ground motion emissions and plan counter measurements. To enhance to development of wind energy as contribution to the exit from nuclear and fossil-fuel energy, expertise is needed to cope with the ground motion emissions of wind turbines.

The potential for the extraordinary island of Iceland to resolve seemingly intransigent problems in Earth Science has long been recognized. Alfred Wegener correctly surmised that his theory of continental drift could be tested there, and the necessary geodetic measurements were started as early as 1938. This, and other geophysical work often produced unexpected results. For example, observations reported before the acceptance of Wegener's hypothesis apparently supported it, while observations reported after its widespread acceptance seemed to contradict it. Iceland has always surprised us. In my presentation I shall report the most recent surprising findings. Long assumed to be one of very few places on Earth where sea-floor spreading can be observed on dry land, this model now requires modification. The convenience of studying oceanic crustal expansion on dry land apparently comes with a price. The crustal extension occurring in Iceland represents not classical seafloor spreading, with or without a mantle plume, but rather the process of continental volcanic margin formation–the process of continental breakup itself. I shall summarize the latest findings of an international group of collaborators of which I am privileged to be a member. I shall outline the rationale for our conclusion that Iceland, far from representing a simple oceanic spreading plate boundary on land, instead comprises magma-blanketed, extended continental crust. This theory is in need of evaluation through the collection of new, independent datasets that can test the predictions of the new model.

One of the most puzzling calcium carbonate minerals is ikaite (CaCO₃ x 6H₂O). Its formation is of particular importance, because anhydrous calcium carbonate minerals occur as pseudomorphs after ikaite. Consequently, ikaite may be an important and frequently forming precursor for more stable carbonate minerals especially in cold environments of Earth (Sánchez-Pastor et al. 2016). Despite the importance of ikaite, its formation conditions are not well constrained and knowledge about its decomposition and transformation is limited. Previous studies showed that cold temperatures and increased alkalinity promote ikaite formation and that dissolved Mg²⁺ and/or phosphate suppress a competing precipitation of calcite and/or vaterite (Purgstaller et al. 2017). However, these studies typically concern homogeneous ikaite formation. Therefore, it is still unknown whether mineral-water interfaces, which are ubiquitous in nature, affect both nucleation and transformation of ikaite.

Using cryo-mixed batch-reactor experiments (CMBR), we investigate which effects mineral surfaces exert on nucleation of ikaite, its subsequent transformation into more stable carbonates and the product phase selectivity. Besides ex-situ analyses of solution compositions and phase inventories of the reactor, in-situ monitoring of solution pH and Ca²⁺ concentrations gives insights into differences and similarities of ikaite behaviour in experiments with and without added minerals such as quartz and mica. Complementary to CMBR, in-situ flow-through cryo-atomic-force-microscopy (CAFM) can reveal the temporal evolution of the reactions on defined substrates in high spatial resolution. Initial results obtained by a newly developed CAFM will be presented.

The Oman Ophiolite is the largest and best-investigated piece of ancient oceanic lithosphere on our planet. This ophiolite was target of the Oman Drilling Project (OmanDP) within the frame of ICDP (International Continental Scientific Drilling Program) which aimed to establish a comprehensive drilling program in order to understand essential processes related to the geodynamics of mid-ocean ridges, as magmatic formation, cooling/alteration by seawater-derived fluids, and the weathering with focus on the carbonatisation of peridotites.

Over two drilling seasons, the OmanDP has sampled the Samail Ophiolite sequence from crust to basal thrust. The total cumulative drilled length is 5458 m, with 3221 m of which was at 100% recovery. These cores were logged to IODP standards aboard the Japanese drilling vessel Chikyu during two description campaigns in summer 2017 and 2018.

Here we present the main results of the working groups of the Universities Hannover and Kiel, focusing on the magmatic accretion of the Oman paleoridge. During 5 field campaigns these groups established a 5 km long profile through the whole crust of the Oman ophiolite by systematic outcrop sampling, providing the reference frame for the 400 m long OmanDP drill cores.

The profile contains 463 samples from the mantle, through gabbros up to the dike/gabbro transition. Identical samples have been analyzed by several methods (bulk rock geochemistry, mineral analysis, Isotope geochemistry, EBSD analysis). The results allow implication on the accretion of fast-spreading lower oceanic crust as well as on the hydrothermal cooling of the deep crust.

The presentation provides an overview about the project “Mass Movements in Germany (MBiD)” jointly implemented by six State Geological Surveys and the Federal Institute for Geosciences and Natural Resources in the period from 2018 to 2020. The objective pursued in this intervention was to review the practical feasibility of the spatial assessment (modeling) of the landslide susceptibility in Germany both at regional and nationwide level. The chosen approach took into consideration the specific framework conditions with regard to the availability and application of official information to evaluate the spatial probability of this hazard in Germany. Focusing on both rotational and translational landslides as well as on rockfall, fourteen modeling case studies were performed in different natural environments to explore limits and possibilities. The methods applied representing state of the art assessment tools covering bi- and multivariate statistical, heuristic, physical and machine learning methods. The necessary model parameters were mainly deduced from nationwide thematic geoinformation layers that are featured by a high degree of consistency. Based on the case studies, conclusions on the applicability of the methods, the requirements for the recorded mass movement inventory, and the use of the selected parameters and parameter classes and their validity were drawn. The results of the case studies culminated in the development of practical solutions and recommendations (workflows), which include the selection of suitable methods according to requirements and the development of reproducible approaches for modeling the regional landslide susceptibility at different scales.

Exploitation of deep geothermal energy is considered as one of the most efficient renewable energy applications. In this sense, reservoir stimulation is established to extract geothermal energy from EGS (Enhanced Geothermal System) which is highly dependent on its in-situ structural properties: damage/shear zones, faults, fractures, its statistics and characteristics. In more detail, damage zones may behave like a conduit providing preferential pathways for fluid flow in otherwise impermeable rock such as granite or gneiss. To improve the reservoirs’ characteristics frequently hydro-shearing or hydro-fracturing are used. It is imperative to account for the natural heterogeneities of the reservoir particularly with respect to the existing fracture network. In this study, we analyze the pre-stimulation fracture network of the EGS experiments conducted at the Grimsel Test Site, in the Swiss Alps. We use original data acquired at the tunnel wall and in boreholes to constrain a probabilistic 3D model further used for H-M simulations of the enhancement experiments. Fracture analysis include scanline mapping, cluster analysis of the spatial distribution and density plots.

Keywords: geostatistics, fracture analysis, DFN modeling, 3D geological modeling, geothermal energy

Numerical simulations of the governing geophysical processes are crucial for geothermal applications in order to characterize the subsurface. This characterization presents us with major challenges ranging from the correct physical and geometrical characterization to the quantification of uncertainties. Quantifying rock physics uncertainties and performing other probabilistic inverse methods is, even with current state-of-the-art finite element solver and high-performance infrastructures, computationally not feasible for complex basin- and reservoir-scale geothermal applications due to the large spatial, temporal, and parametric domain of the applications. Therefore, a common approach is to construct, for instance, models with a lower degree of resolution. The consequence of this is a significant loss of the information content of the model. Hence, with these models, we fail to improve the characterization of the subsurface, as we will demonstrate in this work. As an alternative, we propose to construct a surrogate model by using the reduced basis method. The reduced basis method constructs low-dimensional models while maintaining the input-output relationship. Hence, we do not restrict our physical domain. In this presentation, we demonstrate how this concept can be used for enabling a combined workflow of global sensitivity analysis and uncertainty quantification to improve our understanding and characterization of the subsurface.

Fracture dimensions largely control rock properties like strength and permeability. Thus, knowing their statistical distributions is of great importance in many applied fields of the geosciences e.g., in geothermics, mineral exploration, and hydrology. They are also of academic interest since the statistical distribution of fracture dimensions (length, height, width) might provide inside in fracture formation mechanisms.

However, in the vast majority of cases this information is derived from observations in 2 dimensions, i.e., instead of a fractures length, not the true length, but a fractures-trace length (FTL) is measured. In conclusion information or even estimates about the length of an individual fracture and about the statistical distribution of fracture lengths of a fracture population are not possible.

We analyze the statistical distributions of FTLs mapped at 3 different scales under the application of different mapping schemes that are commonly used to account for the limitations that are unavoidable, when recording fracture lengths in 2 dimensions.

In our study we test how well powerlaw-, exponential-, Weibull-, lognormal-, and log-logistic distributions fit the FTL data. Our results show that FTLs are lognormal distributed independent of scale and mapping scheme and that the parameters of the lognormal distributions reflect outcrop quality and dimension.

In addition, we provide a comprehensive model that explains the observed lognormal distributions of FTLs. This model is based on random restrictions that control the observable FTLs and includes human error and bias in mapping.

Hydro-mechanical (HM) simulations are essential aspects of geothermal reservoir studies to assess the heat production and the associated-environmental impacts, such as seismicity. HM simulations are numerically expensive (especially for large-scale simulations) since they require a relatively fine mesh to capture the complex interplay between the fluid-flow and geomechanical processes. This aspect makes it difficult to perform detailed studies on uncertainties in HM simulations. In this work, we present a comprehensive review and numerical demonstrations about critical elements in HM simulations for geothermal applications. We then discuss potential surrogate models to reduce the computational cost in performing the simulations, specifically for uncertainty quantification and optimization purposes.

There are four important elements in HM simulations for geothermal applications: the equation of state, the porosity-permeability relationship for both the matrix and fracture, the stress-dependent porosity in the matrix and fracture, and lateral and vertical heterogeneities. We compile the discussion from more than 60 papers and numerically show the significance of these parameters using the MOOSE simulator. The incorporation of these parameters into HM simulations leads to realistic descriptions of geothermal applications. However, accommodating for these complex physics also elevates the computational cost.

We compile surrogate-modeling approaches (dedicated for HM problems) from more than 40 papers. The approaches span from reduced-basis to polynomials chaos expansion methods and machine learning approaches. We found that the combination of reduced-basis methods and machine learning approaches enables to effectively deal with non-linearity in HM simulations, to preserve the physics, and to reduce computational cost for further uncertainty quantification.

The analysis of uncertainties in the description of the subsurface is an important aspect for resource exploration and material storage. Because of the complexity of the subsurface and an often inhomogeneous data situation, models exhibit several aspects of uncertainties. These may be caused by the interpolation of locally sparse data and must be considered when constraining a structural geological model. Further, these interpolations may be subject to errors caused by psychological biases, which need to be identified to avoid error propagation during the model building.

The aim of this study is to develop structural geological models of the Cretaceous units of the Münsterland Basin on the basis of stratigraphic boundaries and orientation measurements derived from maps, boreholes and literature as a framework for future geothermal exploration. In the model construction phase, it is attempted to separate processed input data in a first model setup from additional geological assumptions required to obtain geologically meaningful representations. Potential sources for bias are evaluated during the data processing, and standard deviations of input data points are accounted for during a subsequent uncertainty analysis using probabilistic geomodelling approaches.

The resulting structural models reveal the effects and limitations of purely input data-driven models versus models with additional integrated data and the uncertainties derived from different input data types. The integration of results of the planned seismic investigation in 2021/2022 by the Geological Survey NRW and the results of seismic campaigns acquired in the 1970s and 1980s may help to close these knowledge gaps in future work.

Deep geothermal energy is a key to lower local and global CO2 emissions caused by the burning of fossil fuels. Different initiatives aim at establishing deep geothermal energy production at the Weisweiler coal-fired power plant near the city of Aachen, Germany, in order to replace district heat generated as a side product of coal burning. But how much information do we actually have about or need of the subsurface to carry out such a project?

The conducted investigations will provide a 3D geological and probabilistic subsurface model of the area between Aachen and Weisweiler created with the open-source package GemPy developed at RWTH Aachen University. This model is in contrast to established regional models and more detailed local models.

The geological structures between Aachen and Weisweiler represent a SW-NE striking syncline, the Inde Syncline, embedded in the Aachen fold-and-thrust belt. The syncline is offset by Cenozoic normal faults of the Lower Rhine Embayment. The target layers comprise of karstic Lower Carboniferous Kohlenkalk platforms and Upper/Middle Devonian Massenkalk reef carbonates outcropping along the flanks and down faulted within the Lower Rhine Embayment.

Results show that the Aachen fold-and-thrust belt and the down faulted fault blocks can be modeled integrating the available surface and sparse shallow subsurface data. The probabilistic modeling provides information about uncertainties of the target layers in the subsurface. It can be deduced that a planned exploration well for fall/winter 2021 will reduce uncertainties in the subsurface in the vicinity of the target layers enabling improved economic decisions.

In recent years, the deep geological subsurface gained more and more attention as it offers various reservoirs potentially applicable for different geotechnical use options, e.g. deep geothermal energy, geological storage of CO2 and H2/energy. In this context, knowledge about the occurrence and the controlling processes of fluid-rock reactions in space and time is important to guarantee sustainable long-term reservoir utilization. While fluid-rock reactions occur at pore scale, they can significantly influence both reservoir-scale (transport) processes and regional flow regimes. Based on field observations, exemplary fluid-rock reactions in connection with their wide-ranging effects on geotechnical utilizations will be discussed.

During drilling of the Gotthard Base Tunnel through the Central Alps the exposed fractured rocks and the frequent water inflows provided a deep insight into regional hydrogeological processes in orogenic crystalline basements. Here we report data from the 10 km long central Sedrun section. 211 water samples were collected from frequent inflow points at 900 to 2350 m below the surface. The singular samples and data provide a comprehension of the deep hydrochemical cross-section through the Central Alps. The investigated tunnel section cuts across gneisses and schists of the pre-Alpine basement and across two narrow zones of meta-sediments. Rock temperature varies from 30 °C to 45 °C depending on the thickness of the overburden. The fracture water is of meteoric origin and acquires its composition exclusively by chemical interaction with the surrounding rocks along the flow path.

Water from inflow points in the basement of the Gotthard massif has typically a high pH of about 10 and total dissolved solids in the range of 100 to 300 mg L^-1. Sodium is the prime cation of most waters. Although plentiful in the rocks, calcium, potassium, and magnesium are low to very low in the water. The anions associated with Na are carbonate/bicarbonate, sulfate, fluoride and chloride in widely varying proportions. High fluoride concentrations of up to 15.4 mg L^-1 are characteristic for most waters. As a result of the high pH dissolved silica (SiO₂) reached concentrations of up to 58 mg L^-1 and represents 25 - 30 wt.% of the solutes.

During IODP Expedition 382, two sites were drilled at 53.2°S at the northern edge of the Scotia Sea and three sites at 57.4°–59.4°S in the southern Scotia Sea within the Atlantic sector of the Southern Ocean. Sediments at both locations alternate between dominant terrigenous components during glacials and dominant biogenic components, carbonate at the northerly sites and opal in the southern Scotia Sea, during interglacials. Here we constrain the geochemical environment in interstitial waters using the boron (δ¹¹B), silicon (δ³⁰Si) and ⁸⁷Sr/⁸⁶Sr isotopic composition.

Interstitial water δ¹¹B and δ³⁰Si decrease in the uppermost tens of meters downcore, most likely due to in situ weathering processes preferentially releasing light isotopes to interstitial waters. This process is partly also reflected by strongly increasing alkalinities in this depth interval. While δ³⁰Si at all sites increase already at shallow sediment depth where organic matter degradation is intense, δ¹¹B remain relatively low beyond the lower boundary of elevated dissolved phosphate concentrations at every core site. Below this depth δ¹¹B follow isotopic trends seen in δ³⁰Si towards heavy compositions, presumably because of dominating secondary clay formation.

Interstitial waters obtained as deep as 550 and 670 mbsf from the southern Scotia Sea sites reveal an increasing importance of off-axis hydrothermal fluids within the basement underlying the sediments. This feature is detectable by lowest ⁸⁷Sr/⁸⁶Sr alongside lowest Mg/Sr and strongly decreasing δ¹¹B at the lower end of the cores. Our key aim is to illustrate the dominant diagenetic process at each depth downcore, and how to identify these.

Following a thermal and photogrammetric outcrop mapping campaign undertaken at the Waiwera geothermal reservoir in 2019, a pre-existing 3D hydrogeological model was revised in the present study to assess the impact of the updated structural and lithological interpretation on the existing numerical model calibration. For the latter, well data comprising measured temperature and salinity profiles were employed to reconstruct the reservoir’s natural thermal state and spatial distribution of salinity, supported by numerical simulations of density-driven fluid flow coupled with the transport of heat and sodium chloride. In this context, the previously applied fluid equations of state were extended to consider all relevant parameters as functions of temperature and salinity. Our simulation results demonstrate that the undertaken revisions of the static model and fluid properties substantially improve the agreement between the simulated and observed temperature profiles in the monitoring wells, while the achieved match of the simulation results with early recordings on seawater intrusion emphasizes the general model validity. Ongoing work focusses on applying the newly calibrated numerical model to support the sustainable management of the reservoir and to investigate the reappearance of natural seeps at the Waiwera beach, triggered by a decrease in the past excessive groundwater abstraction.

Hydrate formation from dissolved methane in saline solutions is a hydrochemical process, resulting in the accumulation of gas hydrates in sedimentary strata under the seafloor or overlain by permafrost regions. In the scope of the SUGAR framework, LARS has been established to study gas hydrate formation processes and dissociation strategies under in-situ conditions. In the latest hydrate formation experiments, key parameters have been applied to mimic the local marine environment of the Mallik site, Canada. LARS was equipped with temperature sensors and an electrical resistivity tomography (ERT) array for these tests to monitor the dynamic temperature changes and spatial hydrate distribution. Numerical simulation on the hydrate formation process in LARS has not yet been successfully conducted, so that the equations of state relevant to describe equilibrium hydrate formation from dissolved methane have been implemented into a numerical framework and integrated with the TRANsport Simulation Environment to study and quantify the temporal of CH₄-hydrate formation in our present study. We present our model implementation, its verification against HydrateResSim and the findings of the model calibration and validation against the temperature and ERT data from the corresponding hydrate formation experiment. The simulation results demonstrate that our numerical implementation can reproduce the spatial temperature distribution and hydrate formation processes in LARS. Furthermore, spatial hydrate distribution is in good agreement with that produced by ERT measurements undertaken during experiment. Consequently, our numerical simulation framework can be applied for the design of new experiments and to investigate hydrate formation in representative geological settings.

Central Argentina from the Pampean flat-slab segment to northern Patagonia (27-41°S) represents a classic example of a broken retroarc basin with strong tectonic and climatic control on fluvial sediment transport. In this provenance study, we combine framework petrography and heavy-mineral data to trace multistep dispersal of volcaniclastic detritus first eastwards across central Argentina for up to ~1500 km and next northwards for nearly another 1000 km along the Atlantic coast. Compositional signatures reflect different tectono-stratigraphic levels of the orogen uplifted along strike in response to varying subduction geometry as well as a different character and crystallization condition of arc magmas through time and space.

In the presently dry climate, fluvial discharge is drastically reduced to the point that even the Desaguadero trunk river has become endorheic and orogenic detritus is dumped in the retroarc basin, reworked by winds, and temporarily accumulated in dune fields. At Pleistocene to early Holocene times, instead, much larger amounts of water were released by melting of the Cordilleran ice sheet or during pluvial events. The sediment-laden waters of the Desaguadero and Colorado rivers then rushed from the tract of the Andes with greatest topographic and structural elevation, fostering alluvial fans inland and flowing in much larger valleys than today toward the Atlantic Ocean. Sand and gravel supply to the coast was high enough not only to promote rapid progradation of large deltaic lobes but also to feed a cell of littoral sediment transport extending as far north as the Río de la Plata estuary.

The grain-size distribution of sediment particles is an important aspect of the architecture of submarine fans and lobes. It governs depositional sand quality, and reflects distribution of particulate organic carbon and pollutants. Documenting the grain-size distribution of these deep-marine sedimentary bodies can also offer us an insight in the flows that deposited them. Submarine lobes are commonly assumed to linearly fine from an apex, meaning there should be a proportional relation between grain size and distance from the lobe apex. However, not much detailed quantitative work has been done to test this hypothesis. Exposure of a 5 km long dip-section of basin-floor lobes in Clinoform 12, Battfjellet Formation, Spitsbergen, enable the study of basinward grain-size evolution in lobe deposits. Furthermore, the dataset allows testing if there are any documentable grain-size differences between lobe sub-environments.

The results show that fining of lobe deposits occurs predominantly in the most proximal and most distal parts of the lobe, while the intermediate lobe, which is dominated by lobe off-axis deposits, is characterized by a relatively consistent grain-size range. Lobe sub-environments show statistically distinct grain-size distributions from lobe axis to lobe fringe. An explanation for these trends is the interplay of capacity and competence-driven deposition with the grain-size stratification of the flows.

The outcomes of this study help to better understand the proximal to distal evolution of turbidity currents and their depositional patterns. They also provide important insights in reservoir potential of basin-floor fans at lobe scale.

Compositional data on heavy minerals is fundamental in sedimentary provenance analysis. Typically, this data is gathered by optical microscopy and more recently, by mineral chemical analysis (MLA, QEMSCAN) or Raman micro-spectroscopy. In silt-sized sediments optical microscopy is unfeasible. We introduce a systematic and highly efficient approach to assess the heavy mineral composition in fine grain-size fractions (10-30 µm and 30-62 µm) by Raman micro-spectroscopy.

The approach starts with a web-application that creates and visualizes large mosaic images from which arbitrary objects can be selected for training and inference of a region-based convolutional neural network (R-CNN). Here, mineral grains are automatically selected by passing the tiles of a mosaic image of the sample slide into the R-CNN. For each detected grain a polygon is computed from which positional and optical parameters are derived. Using this polygon data, the measurement parameters at the Raman spectrometer are individually set to account for varying Raman scattering intensities and irradiation resistivity. After the compositional data is obtained, Raman spectra are evaluated and further single-grain geochemical methods (ICPMS, EMPA) can be applied to the identified and referenced grains (e.g. U-Pb dating of zircon).

The method was tested on 13 samples from three loess profiles from Germany and Hungary. About 100.000 minerals were analyzed and provenance signals demonstrate clear contrasts between the sections. Being automated, this approach allows for analyzing large sample numbers with higher precision (i.e. counting statistics) on silt-sized materials, thus opening new avenues in sedimentary provenance analysis.

The Zambezi River rises at the center of southern Africa, flows across the low-relief Kalahari Plateau, meets Karoo basalt, plunges into Victoria Falls, follows along Karoo rifts, and pierces through Precambrian basement to eventually deliver its load onto the Mozambican passive margin. The river is subdivided into segments with different geological and geomorphological character, a subdivision fixed by man’s construction of large reservoirs and testified by sharp changes in sediment composition. Pure quartzose sand recycled from Kalahari desert dunes in the uppermost tract is next progressively enriched in basaltic rock fragments and clinopyroxene. Sediment load is renewed first downstream Lake Kariba and next downstream Lake Cahora Bassa, documenting a stepwise decrease in quartz and durable heavy minerals. Composition becomes quartzo-feldspathic in the lower tract, where most sediment is supplied by high-grade basements rejuvenated by the southward propagation of the East African rift. Feldspar abundance in Lower Zambezi sand has no equivalent among big rivers on Earth and far exceeds that in sediments of the northern delta, shelf, and slope, revealing that provenance signals from the upper reaches have ceased to be transmitted across the routing system after closure of the big dams. This high-resolution petrologic study of Zambezi sand allows us to critically reconsider several dogmas, such as the supposed increase of mineralogical “maturity” during long-distance fluvial transport, and forges a key to unlock the rich information stored in sedimentary archives, with the ultimate goal to reconstruct the evolution of African landscapes since the late Mesozoic.

The Blue Nile River Basin contains a thick fluvio-lacustrine sediment succession of Permian to Jurassic age. Its evolution is linked to extensional tectonics during break-up of Pangea in the aftermath of the Carboniferous-Permian glaciation. We collected sandstone samples from several sections in order to study the tectonic evolution and possible impacts of environmental perturbation around the Permian-Triassic boundary. Based on thin-section petrography, bulk-rock geochemistry, heavy mineral spectra, and detrital zircon U-Pb ages we are able to establish a provenance model for the Permian-Triassic basin-fill evolution. The results reveal distinct differences between Lower Permian and Upper Permian to Upper Triassic sediments. The Lower Permian sandstones are rich in feldspar, carbonate cement, and relatively unstable heavy minerals like apatite and garnet. The chemical index of alteration and trace elements suggest little chemical weathering and proximity to the source area. Upper Permian to Upper Triassic sandstones, however, contain a large amount of ultra-stable heavy minerals, and geochemical data point to intense chemical weathering, reworking and/or recycling. In the Lower Permian, detrital zircon U-Pb age spectra are dominated by Pan-African and Tonian ages, whereas Upper Permian and Upper Triassic samples show a higher proportion of old zircons and young zircons (c. 1 Ga and c. <541 Ma) probably from intraplate magmatic rocks. The results show that during the Upper Permian and Triassic, uplift and unroofing was happening accompanied by climate change.

The Gross Brukkaros (Namibia) reflects a broad dome structure showing a crater-shaped depression with numerous peripheral beforsitic carbonatite dykes. These dykes frequently contain an extreme load of basement (Nama-group) xenoliths (> 60 vol.%) including shales, quartzites, granites and gneisses. While xenoliths of exposed country rocks (mainly shales) show an angular habit, a pronounced rounding of xenoliths from other lithologies proves a wide transport and strong abrasion. This consumption of xenolithic material may result in remarkable contamination of the carbonatitic magma. MicroXRF mapping and optical microscopy provides first evidence that the corrosion and alteration of crustal xenoliths is controlled primarily by the xenoliths´ mineralogy and geochemistry. While some xenoliths exhibit distinct zoning reflecting a progressive leaching, others appear to be relatively inert. This proves the Gross Brukkaros of being an ideal natural laboratory to study the influence of crustal contamination in the carbonatitic system, particularly at the subvolcanic-volcanic depth transition. On the other hand, cross-cutting carbonatite dykes generated diatremes almost completely composed of quartz. A closer proximity to the diatreme yields an increase of the Si content in the dykes. In some cases, dykes occur with an extremely high proportion of microscopic xenolith fragments (>95 vol.%) and only subordinate proportions of carbonate. This indicates evaporation of the carbonatite melt during eruption, while the inherent Si remains as a residue along with the xenolith fragments and is precipitated in the diatreme breccia. Combined with C and O isotope systematics, carbonate crystallization is suspected to have proceeded under super-cooled conditions at ~150 °C.

The Chico Sill Complex (Northeast New Mexico) is the result of magmatic episodes from ~37 Ma to 20 Ma and produced a diverse and compositionally discontinuous suite of mostly intrusive silica-saturated and silica-undersaturated rocks. The Chico Phonolite was emplaced ~ 26 to 20 Ma in dikes and large sills. Sills of different composition may be stacked 2 and 3 thick. They bear no chemical affinity to the bulk of other rocks in the complex based on normalized trace element diagrams. Candidates for parent melts are scarce. At least two distinct trends are noted in Zr-La Space. A higher-Zr trend includes dikes and three sills and may represent evolution of a primary phonolite melt. The most-evolved sill (Point of Rocks Mesa) is the last-gasp of phonolite magmatism and likely the companion immiscible silicate for a calciocarbonatite dike 10 km distant.

Calciocarbonatite is a miniscule portion of the complex (outcrop limited to a few hundreds of m²⁾. The carbonate mineral is impure calcite (Mn>Fe>Sr>Mg>>Ba) in matrix goethite. Other minerals present include barite, pyrite, and REE minerals containing Ca and Ca-Ti next to the calcite. Normalized Ba, Th, REE, Y and Sr show 100 times enrichment in the carbonatite. Mineralogy, texture, and O-C isotopes suggest that the original carbonatite melt may have been more sodic and experienced alteration similar to that of lavas at Oldoinyo Lengi. Owing to the distance between outcrops, the separation of the melts (and phonolite evolution) occurred at much greater depth.

Nephelinites are strongly SiO₂-undersaturated volcanic rocks that are often associated with phonolites and carbonatites. In the Gregory Rift in East Africa several major nephelinitic-phonolitic volcanoes occur, with some of them being associated with carbonatitic rocks (e.g., Oldoinyo Lengai, Kerimas, Mosonik, Shombole, Meru), while others lack carbonatites (e.g, Sadiman, Essimingor, Burko). We characterize the magmatic evolution of the Burko volcano and compare our results with published data from spatially associated nephelinite-phonolite±carbonatite associations in the Gregory Rift and elsewhere.

Overall, nephelinites show mineralogical differences, are variably evolved (in terms of X_Mg, LILE and HFSE), and in some cases peralkaline (Na+K/Al >1) nephelinites do occur. Besides nepheline, clinopyroxene and apatite, garnet, magnetite, perovskite and titanite are magmatic phases in most cases. However, magmatic ne-cpx-grt-ttn assemblages can be distinguished from those with ne-cpx-mag-prv. Other phases, such as wollastonite, melilite, combeite, aenigmatite, sodalite and others are restricted to some occurrences and resemble different geochemical flavors of nephelinites, different crystallization conditions, variable differentiation stages and different levels of peralkalinity. Redox- and silica activity-dependent phase equilibria allow for constraining and comparing the magmatic evolution of the different localities by combining textural with mineral chemical data.

In general, high redox conditions above FMQ and peralkalinity seem to favor the formation of carbonatites. However, in several cases that meet these conditions, no carbonatites are exposed and worldwide, carbonatites are often associated with nephelinites that are not peralkaline. We discuss the potential for nephelinites to exsolve carbonate-rich liquids based on a petrological and geochemical comparison of different occurrences.

Foidites and melilitites are strongly SiO₂-undersaturated rocks that form by extremely low degrees of partial melting of the metasomatically overprinted lithospheric mantle. In Central Europe, they occur in volcanic fields, dike swarms or as isolated stocks and diatremes.

Our detailed study on foidites from SW Germany indicates two distinct age groups with marked differences in mineralogy and mineral chemistry: Based on in-situ U‑Pb age data (apatite, perovskite, zircon) a Miocene cohort (~ 9–19 Ma) of predominantly olivine melilitites and melilite-bearing nephelinites can be distinguished from a much older Upper Cretaceous to Lower Eocene group (~ 48–68 Ma) of melilite-free nephelinites and nepheline basanites. This contrasts with previous K-Ar whole-rock and mineral data suggesting continuous magmatism between 90 and 6 Ma.

The older group is characterized by the frequent occurrence of green core pyroxenes, hydroxyapatite, and minor feldspar, whereas the younger group contains melilite, late magmatic fluorapatite, Ba- and F-rich mica and occasionally perovskite, but no feldspar. It crops out in the Freiburger Bucht and the Bonndorf Graben, the Vosges (France), the Odenwald and Kraichgau region, in the Taunus and the Lower Main Plain, whereas the younger group is represented by occurrences in the Hegau, the Urach region and the Central Upper Rhine Graben including the Kaiserstuhl.

As part of the Central European Volcanic Province, the spatial distribution and age of these rocks reflect regional tectonic events, while the petrologic contrasts between the two age groups indicate heterogeneous crystallization conditions and/or magma source variations such as different formation depths.

The Gardiner (E-Greenland) and Kovdor (Russia) alkaline complexes display a similar succession of rock types comprising dunites-pyroxenites, ijolite series rocks, melilitolites and carbonatites. Although similar melanephelinitic parental magmas are suggested for both complexes, they display enrichment in HFSE at strikingly different evolutionary stages: At Kovdor, melilitolites are barren but carbonatites are mineralized with HFSE. In contrast, melilitolites at Gardiner contain ore-grade accumulates of perovskite having wt.%-level contents of Nb, Ta and REE, while associated carbonatites are barren. Previous studies suggested that HFSE-poor carbonatites at Gardiner were formed by liquid immiscibility while Kovdor carbonatites result from fractional crystallization and retained high HFSE contents. These two evolutionary trends were explained by a different CO₂-dependent stability of melilite vs. clinopyroxene+nepheline+calcite during the ijolite stage [1]. However, it is poorly investigated how the HFSE budget is affected by the crystallization of Ti-phases during different stages of the magmatic evolution, which are stabilized depending on magma composition (i.e. aTiO₂, aSiO₂) but also on intensive parameters such as P, T, and fO₂ [2]. Preliminary results suggest that, in contrast to Kovdor, magmas at Gardiner had physiochemical conditions which favoured abundant crystallization of Ti-phases along with co-precipitation of HFSE earlier in the sequence. This is supported by (1) pyroxenites with abundant Ti-magnetite and ilmenite, (2) titanite-rich ijolites and (3) perovskite-rich melilitolites. Possibly, Ti-rich melts reflect a distinct mantle regime beneath E-Greenland, which also produced anomalously Ti-enriched flood basalts ~6-10 Ma before.

[1] Veksler et al. (1998) J.Pet. 39, 2015-2031; [2] Marks et al. (2008) CG 257, 153-172

Halogen (F, Cl and Br), S and δ³⁷Cl variations within grains of Cl-rich minerals sodalite and eudialyte from peralkaline rocks of the Ilímaussaq intrusion were determined using Secondary Ion Mass Spectrometry (SIMS). Samples show either sodalite and eudialyte in direct contact, or sodalite/eudialyte embedded in Cl-free minerals (nepheline, feldspar). Comparing samples allows deciphering potential halogen and S exchange between these minerals during rock cooling.

Results suggest that sodalite (7 wt%) and eudialyte (1.2 wt%) have remarkably constant Cl concentrations. In samples with adjacent sodalite and eudialyte F increases at sodalite boundaries and decreases at eudialyte boundaries. In sodalite not in contact with eudialyte F concentrates at the edges, something obscured by F-rich inclusions. In eudialyte not in contact with sodalite F is constant with no variations at the edges. Br is also constant in eudialyte, but in sodalite its concentration decreases towards the edges. S also is constant in eudialyte, and concentrates significantly at the edges of sodalite, especially strongly if sodalite contacts eudialyte. In hydrothermal eudialyte Cl is low at the edge with higher concentrations away from the edge. Br and S correlate with Cl while little F variation is observed.

δ³⁷Cl in eudialyte is higher than in adjacent sodalite. Within individual grains δ³⁷Cl is higher at the edges than in the centre. Between sodalite grains δ³⁷Cl can vary a few tenths of a permille, while between eudialyte grains, variations can even be higher. In hydrothermal eudialyte δ³⁷Cl increases significantly at the grain boundary with values up to +3.5‰.

Prof. Vening Meinesz opened up the oceans for high precision gravimetric observations. Today, his submarine adventures are an inspiration to my science and education in gravimetric research. We wil follow him along his voyage aboard the K18, along which I will discuss several applications using global gravity field models. The theory of isostasy allows us the use the static gravity field to study GIA processes in Fennoscandia and North America. Also, observed crustal structure from active seismic experiments can be used to correct the gravity field and study the upper mantle. With a regional crustal model of the British Isles and surrounding oceans I was able to study the density variations in the lithospheric mantle underneath the crust. This study revealed a highly varying upper mantle density signature, but compared with seismic tomography large differences were seen. We show that this mismatch can be traced back to regularisation techniques used in seismology. This opened up the the study of mantle convection and its interaction with lithosphere. Seismic-derived mantle anomalies are still highly uncertain but might be improved with future gravity-rate datasets. Preliminary studies show potential in reducing the uncertainty in viscosity structure of the Earth. Finally, with the GOCE mission, a new boost has been given to the use of gravity gradients, I discuss an approach in inverting the full gravity gradient tensor estimating density structure of a subducting plate. By showing this variety of studies, I hope to inspire you to use satellite-derived global gravity fields.

The international networking initiative AlpArray Gravity Research Group (AAGRG) focused on the compiling homogeneous surface-based gravity datasets across the Alps and adjacent areas, on creating digital data sets for Bouguer and Free Air anomalies. In 2016/17 all ten countries around the Alps have agreed to contribute with point or gridded gravity data and data processing techniques to a recompilation of the Alpine gravity field in an area which is limited by 2° to 23° East and 41° to 51° North. For this recompilation, the group rely on existing national data.

The AAGRG decided to present the data set of the recalculated gravity fields on a 2km x 2km and 4km x 4km grid for the public. The densities used are 2670 kg/m3 for landmasses, 1030 kg/m3 for water masses above and -1640 kg/m3 below the ellipsoid. The correction radius was set to the Hayford zone O2 (167 km). The new Bouguer anomaly is compiled according to the most modern standards and reference frames (both location and gravity). Geophysical indirect effect and atmospheric corrections are also considered. In the Western Mediterranem (Ligurian Sea) completely reprocessed ship data of the Service Hydrographique et Océanographique de la Marine/Bureau Gravimétrique International were used. Marginal parts of the map were filled by GGM data.

Main aim of the work of the AAGRG is to release a gravity data base which can be used for high-resolution modelling, interdisciplinary studies from local to regional to continental scales, as well as for joint inversion with other datasets.

We present a high-resolution investigation of the Ivrea Geophysical Body (IGB) at intra-crustal scales in the Western Alps. The IGB is a sliver of Adriatic lower lithosphere, located at anomalously shallow depths, and presenting positive gravity and fast seismic anomalies. Despite comprehensive information from previous studies, structural questions persist on the IGB and on its structural relation with the Ivrea-Verbano zone (IVZ), which exposes lower-to-middle crustal composition outcrops at the surface. Therefore, we measured 207 new gravity data points, obtaining a coverage of ca. 1 point every 4-to-9 km² across the IVZ, and we installed 10 broadband seismic stations (IvreaArray) along the linear West-East profile of Val Sesia, operated for 27 months. We compiled a surface rock-density map and used it to define the density-dependent terrain-corrected “Niggli” gravity anomaly to properly model the IGB density structure at depth. We modelled the IGB as a 3D, single density-contrast interface, obtaining 400 ± kg·m^-3 as optimal density contrast and a 20-km wide protruding structure, as shallow as 1 ± 1 km below sea level. The seismic data was then used to constrain the IGB shape along the 2D Val Sesia cross-section by means of a joint inversion of seismic receiver functions and gravity anomaly data. This has confirmed the marked density contrast and shallow segments reaching 1 to 3 km depth below sea level, and provide agreement with the rock’s physical properties (ρ, v_S) and the geological structures observed at the surface. These results are now published (doi:10.1093/gji/ggaa263 and doi:10.3389/feart.2021.671412).

The data sets presented here are used for the preparations of a 3-dimensional modelling of the gravity field in the Western Mediterranean/Ligurian Sea. As part of the AlpArray initiative and the German priority program MB-4D, various compilations of the gravity field are available: Bouguer and Free Air Anomaly, as well as variously calculated residual fields that provide new insight into crustal and lithospheric structures. The anomalies have been processed according to modern standards. The recalculations were part of the research of the international AlpArray Gravity Group. In particular, the residual fields in the area of the Ligurian Sea show hitherto unknown small-scale anomalies after subtraction of long-wave components (satellite gravimetry). The short wavelengths in the gravity field of different magnitudes suggest strong structuring of the lithosphere e.g., offshore Marseille (with an anomaly of about 60 mGal and in the areas between the French-Italian mainland and Corsica-Sardinia (with up to 100 mGal). Furthermore, the new compilations suggest that the crustal underground of this area is not formed by a uniform basin, but by domains of rather different densities. The Italian coastal region between Genoa and Livorno is characterized by a belt of positive anomalies (up to 60 mGal). The subsurface beneath the two islands of Corsica and Sardinia is characterized by strong negative anomalies in the residual field, indicating density deficits beneath. The new findings are supported by applications of Euler deconvolution, gradient methods, directional filters, and curvature calculations considering also the evaluation of GOCE gradients.

The Bohemian Massif represents the largest exposure of rocks deformed during the Variscan orogeny. Western Carpathians form an arc-shaped mountain range related to the Alpine orogeny. In our study, the lithospheric structure of the key tectonic units in the area and their contact zone was analyzed by 2D gravity modelling along the NW-SE oriented CEL09 profile of the CELEBRATION 2000 seismic experiment. New gravity map compiled at the initiative of the AlpArray Gravity Research Group was used. This map is based on a uniform reprocessing of the national terrestrial gravimetric databases of ten countries of the wider Alpine region. The resultant 2D density model based on gravity data was constrainted by results of seismic reflection and refraction method. Applied densities were defined by transformation of the modelled P-wave velocities. A good correlation between the density and seismic models was shown. The resultant 2D density model consisting of five principal layers (sediments, upper crust, lower crust, lower lithosphere and asthenosphere) shows differences between the older, cooler and thicker Bohemian Massif (in average: ~32 km thick crust, and ~120 km thick lithosphere), and the younger, warmer and thinner Carpathian-Pannonian region (~28 km crust, ~95 km lithosphere). The detected contact is delimited by a change in the Moho and the LAB topography, and assumes an overthrusting of the Western Carpathians onto the Bohemian Massif by ~30 km resulting in a neo-transformation of the crust/mantle and related lithosphere after subduction.

The Ligurian Sea in the western Mediterranean Sea is a back arc basin created through the Apennines Calabrian subduction zone between 30 and 15 Ma ago. The inner geological structure of this basin is not well known. To improve the knowledge about the density distribution of the crust and lithosphere, we performed a pre-processing of gravity data prior to 3D-modelling. This work is related to research in the MB-4D priority and AlpArray project.

The satellite gravity gradients from GOCE were directly interpreted and used for filtering of different wavelengths to calculate residual fields, Bouguer and Free-Air anomalies as well as invariants and Euler-Deconvolutions. Furthermore, seismic profiles from several ship-borne surveys as well as OBS measurements of the AlpArray project (LOBSTER, GEOMAR, Kiel) and bathymetry data contributed additional information.

The processed data show an unknown anomaly offshore Marseille and the possibility of several underground structures with different densities. The basin itself is characterized by a mass surplus and positive anomalies with a maximum between Corsica and north-west Italia, while the anomalies underneath Corsica and Sardinia are neutral to negative.

The derived information will be used in the 3D-modelling software IGMAS+ to execute an inversion for the area and create a model of the mass distribution beneath the Ligurian Sea and its margins.

Sicily is a part of the central-Western Mediterranean area and represents a geotectonic boundary between the African and European plates. It is the result of a complex geological process based on a polyphasic evolution of a compressional step beginning with the Oligocene-Miocene clockwise rotation of Corsica-Sardinia simultaneously with the extensional processes of the Tyrrhenian basin. Consequently, the area is constrained by the continuing partial advance of the Sicilian-Maghrebian chain southwards and the Tyrrhenian extensional area towards the internal foreland areas (Hyblean domain). The study focuses on the creation of a 3D lithospheric-scale model of a 300 km x 400 km extended area in the central Mediterranean domain (Lat38°, Lat35°), which is consistent with the available geological and geophysical data, as well as with the observed gravity field. The reconstructed (simplified) geological setting consists of a lithospheric mantle, a crystalline basement (continental and oceanic crust), carbonates, the European margin and the Neogene-quaternary cover including volcanic bodies. The work aims to investigate the geometry of lithosphere integrating tomographic models in order to assess the major density contrasts and the lithospheric thermo-mechanical state. The regional 3D model provides also the boundary conditions for local thermal models to investigate afterwards.

Geoscientific studies in Antarctica are extremely challenging due to the remote location of the continent, its harsh environment and difficult logistics. Additionally, the continental crust is covered by an up to 5 km thick ice sheet, which makes surface based geoscientific studies extremely difficult. Gravity field measurements and gravity based subsurface models are therefore essential in studying the structure, properties and processes of the Antarctic subsurface.

In the last decades a large database of airborne, shipborne and ground based gravity data has been compiled. Recently, all existing and new gravity data were processed to infer an enhanced gravity field solution for Antarctica.

Subsequently, this new gravity field solution can be used for further geophysical studies. We use gravity disturbances to study subglacial topography, sediment thickness and Moho depths to improve respective existing models in Antarctica.

Studying these parameters on a continental scale, we apply 2D Parker-Oldenburg inversion in combination with results from other gravity based studies and further constraining data.

Additionally, we make use of the higher resolution of the new gravity grid (5 km) to study smaller regions in more detail, specifically the Weddell Sea area and Queen Mary Land. Here, we use gravity forward modelling constrained with ice penetrating radar and seismic data to infer geometric structure and densities of the subsurface.

In this contribution we present results of the Parker-Oldenburg Inversion and discuss the underlying parameters. Also, we show the resulting 3D forward models of the Weddell Sea area and Queen Mary Land.

Hydrocarbon seepage is widespread distributed at the southern Gulf of Mexico. During several research cruises in 2003, 2006, and 2015 (SO174, M67/, and M114) we used multidisciplinary approaches, including multi-beam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits occur at numerous knolls and ridges in water depths from 1230 to 3150 m. These striking seafloor elevations are formed by diapirs of Jurassic salt deposit associated by hydrocarbon accumulations. The deeper sites like Chapopopte and Mictlan knolls were characterized by asphalt deposits accompanied by extrusion of liquid, and very heavy oil in form of whips or sheets, and in most places by gas emissions, and the presence of gas hydrates (Tsanyao Yang, Mictlan, and Chapopote knolls). Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh solidified asphalt structures were settled by bacterial mats and vestimentiferan tube worms growing through cracks and from under the edges of pavement. The gas hydrates at Tsanyao Yang and Mictlan knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1–2 m long tube worms, bivalves, snails, and shrimps. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.

Cliffs line many erosional coastlines. Localized failures can cause land loss and hazard, and impact ecosystems and sediment routing. Links between cliff erosion and forcing mechanisms are poorly constrained, due to limitations of classic approaches. Combining multi-seasonal seismic and drone surveys, wave, precipitation and groundwater data we study drivers and triggers of 81 failures along the chalk cliffs on Germany’s largest island, Rügen. We have found that marine processes are negligible in triggering failures but efficient in removing the deposits. Instead, cliff failure has been associated with terrestrial controls on soil moisture and groundwater. During the vegetative season, evapotranspiration impedes groundwater flow into the cliff face. When vegetation is dormant, failure frequency correlates with lunar-mediated precipitation. Failures are triggered by relative air moisture and rain, leading to clustered events during night time. Drier terrestrial conditions prevent smaller failures, which causes beach erosion and ultimately prepares the cliff for sector collapse.

Numerous studies on submarine iron-rich sediments (BIF, ironstones, etc.) focus on environmental changes and ocean chemistry, however, many questions related to underlying hydrothermal processes remain unresolved. As proximal chemical sediments, Lahn-Dill-type iron ores can provide insight into mechanisms of hydrothermal seafloor alteration related metal scavenging, and subsequent Fe-mineral deposition.

Lahn-Dill-type iron ores formed during the Middle/Upper Devonian within the Rhenohercynian back-arc basin associated with intraplate alkali basaltic volcanism. Ores formed on top of volcanogenic successions proximal to centres of volcanic activity. Typically, they occur as hematite-(siderite-)quartz ores reaching up to 60 wt.% Fe. We sampled a 5 m profile within the Fortuna mine in the eastern Rhenish Massif (Lahn syncline, Germany) and conducted a detailed petrographic study and whole rock ICP-MS as well as in-situ LA-ICP-MS geochemical analyses.

Iron is commonly mobile under reducing and acidic conditions. However, geochemistry of Lahn-Dill-type iron ores indicates that hydrothermal fluids may have been able to mobilise HFSE pointing at possible alkaline fluids. This is suggested by positive correlations of Fe with certain HFSE including Zr and HREE. Upon venting into seawater, iron likely precipitated as oxyhydroxides that preferably scavenged Si, W, Mo, Pb and V complexes from seawater by sorption. Subsequent deposition on the seafloor as a Si-Fe-rich gel is indicated by crescent-shaped shrinking cracks. Today, mineral assemblages within ore are characterized by fused hematite mats, hematite dispersed in quartz and/or siderite and microcrystalline quartz that may either be interpreted as diagenetic dissolution-precipitation processes, cyclic changes in primary fluid composition, or potentially both.

Exploration of carbonatite-associated REE-deposits is challenging due to heterogeneous ore distribution and variable and often complex ore mineralogy. The Kieshöhe carbonatite in SW Namibia represents a subvolcanic occurrence hosting dolomite, calcite and ankerite carbonatite dykes, ring dykes and diatremes. Petrography, whole rock geochemistry and microXRF imaging provide insights into the role of silicate xenoliths for the REE mineralization in a subvolcanic environment. Xenolith-rich carbonatites are relatively REE-poor with only minor monazite mineralization, whereas xenolith-free carbonatites show high REE-contents incorporated primarily into REE-F-carbonates. Moreover, the additional presence of barite and pseudomorphic replacement of hexagonal precursor minerals suggest the former presence of burbankite, which might represent the potential REE source. The strong association of REE-minerals, barite and quartz furthermore indicates the simultaneous hydrothermal transport of REE, Ba, S and Si. In particular, Si-saturated hydrothermal fluids promote the potential of sulfate complexes to mobilize REE [1]. Since an enhanced xenolith resorption in xenolith-rich parts of the complex increases the Si content of the hydrothermal fluid and thus the capacity of REE transport, REE precipitation is inhibited in such sections but supported in xenolith-free sections. This demonstrates that xenolith entrainment not only has a strong influence on REE mineralization in synmagmatic stages [2], but may also have strong effects in post-magmatic hydrothermal stages of the carbonatitic system. This observation can potentially be used as a first-order field-based exploration indicator for REE-mineralization in carbonatites.

[1] Cui et al. (2020). Geology, 48(2), 145-148.

[2] Giebel et al. (2019). Journal of Petrology, 60(6), 1163-1194.

Due to the closure of coal mining in the northwestern German coalfields, active mine water drainage becomes technically redundant. As a result, the rising mine water table affects the subsurface stress conditions and may induce heterogeneous ground movements of fault blocks. Petrophysical properties of the Upper Carboniferous (Westphalian A and B) rocks are crucial to understand subsurface behavior during mine water rise. As a part of the interdisciplinary FloodRisk project, we present a petrophysical and petrographical characterization of Westphalian A and B drill cores from the Ruhr area.

Based on fining-upward cycles consisting of basal sandstones (medium-grained, planar laminated) followed by siltstones with intercalated lower (planar/wavy laminated to bioturbated/rooted) mudstones and coal seams at the top, that are locally overlain by clayey deposits, the rock succession was interpreted as fluvio-deltaic facies association. Petrophysical measurements on core plugs indicate that most samples are generally tight (mean permeability: 0.26 mD; mean porosity: 6.4 %) but reservoir properties vary by grain size and facies. Petrographic analyses indicate that sandstone cementation is dominated by ferroan carbonate (mostly siderite and Fe-calcite) and quartz overgrowth in the pore space. Locally, veins are cemented by ferroan calcite or sulfides. Feldspar-rich rock fragments are often replaced by kaolinite, reducing the secondary porosity.

The outcome of this investigation will be integrated into an interdisciplinary model that involves geomechanical, geodetic and geophysical data in order to understand subsurface flow. Furthermore, data can be used to consider the fluid distribution for potential geothermal energy use.

Das natürlich geschlossene System (NGS), das von (Stensen Niels 1669) begründet wurde, ist ein Modell des Komplexes von exakt gemessenen Parametern dualer Gesteinssysteme der Geologie. Die angewandte Messtechnik in den Geowissenschaften deduziert funktionale Zusammenhänge der Proportionalität (h = m) und (h = - m + C). Die Umformung der Funktionen liefert die Invarianten des geologischen Binärsystems (h/m = ±1). Die Funktionen stehen orthogonal aufeinander, sie sind symmetrisch, invers und relational. Reflexive Messwerte (Offhaus 2020) bestimmen die Lagerung der Gesteinssysteme, während die Lote (geologische Profile), im Unterschied zur Lagerung, transitive Eigenschaften aufweisen. Transitive und reflexive Werte liegen in der Geologie partiell übereinander. Die arithmetische Relation (h = - m + C) hat neben der Transitivität die besondere Eigenschaft der Identität von Funktion und Umkehrfunktion durch den Betrag des Anstiegs von (- 1). Inzidenzmatrix und gerichteter Graph (Metz 2010) belegen die Einheit und Verflechtung der Eindeutigkeit dualer Gesteinssysteme in der Geologie. Das NGS hat die Eigenschaften der Symmetrie, der Reflexivität, der Transitivität, es ist nicht antisymmetrisch und nicht asymmetrisch, somit ist es Äquivalenzrelation und Halb- oder Quasiordnung.

Die mathematischen Anwendungen in der Geologie, wie z.B. (Bentz A. 1961); (Eisbacher Gerhard A. 1996), die Verknüpfung von geologischen Prozessen der Tektonik mit der mathematischen Eigenschaft von „Umkehrfunktionen“ zum geologischen Begriff „Inversionstektonik“ (Kley J. 2013) oder die Anwendungen der Session „vorwärts und inverse Modellierung“ von geologischen Daten (Matenko L. u.A. 2020) verifizieren das NGS. Ebenso bestätigt die ausführliche Formenanalyse von Windkantern (R. Schwenecke 2020) die theoretischen Aussagen des NGS mit gemessenen Daten von ca.1000 Windkantern in vollem Umfang, darüber hinaus Verbindungen zur Skaleninvarianz und zur Selbstähnlichkeit.

Das geologische Modell des NGS ist ein mathematisches Objekt, das sich zur Entwicklung einer theoretischen Geologie eignet.

The energy dialog varies by economic status. Western Europe and the United States suggest there is clean and renewable vs dirty and non-renewable energy, and further that clean energy is cheaper than dirty energy. In this narrative, carbon neutral drives the dialog. Some propose to eliminate coal, oil and even natural gas and nuclear altogether, and suggest that solar, wind and batteries can power the world and address climate change. The IEA just released a report on how net zero carbon might be accomplished by 2050. Notwithstanding the assumptions, which require scale and magnitude changes never before seen, the greater underlying assumption is that the emerging and developing world will participate. A different narrative exists in much of the rest of the world, led most profoundly by SE Asia, but also Africa, Latin America, the Middle East and to some degree Russia. Here billions of people seek affordable and reliable energy to lift themselves into economic prosperity. Here the energy transition is best interpreted by examining actions, not rhetoric. Emerging and developing economies have acted to feed their substantial and growing energy appetite with coal and hydro, with natural gas and nuclear growing, and solar and wind getting started but still very small relative to total consumption. Further, although the environmental concerns of the developing world include climate, they are more acutely focused on economic growth, which will then allow them to curb population growth as has been done in the US and Western Europe, and begin to reduce pollution of water, soil, and air. Given this dialog duality, a truly sustainable energy future must eradicate energy poverty while also going nature neutral-- minimizing the impacts of all forms of energy on air, land, water, and the atmosphere.

“Digital sedimentary petrology” models represent the microstructure of clastic rocks in 3D and use forward process models to simulate diagenesis in response to evolving burial conditions. This modeling approach predicts textures and morphologies that can be readily compared with natural samples and laboratory experiments. These models are useful tools for studying diagenetic processes and also are designed to predict rock microstructure in undrilled areas of the subsurface.

Digital petrology models are natural counterparts to “digital rock physics” models that use rock microstructure as input when simulating a broad array of fluid transport and geomechanical properties. Linking these models extends digital rock physics models beyond assessment of rock properties based on scans of physical samples to predicting rock properties in undrilled portions of the subsurface. Applications of this coupled modeling approach includes hydrocarbon and geothermal energy exploration and production, CO₂ sequestration, hydrogen and compressed air storage, wastewater injection, and groundwater studies.

Our work to date on the development of the Cyberstone™ digital sedimentary petrology model involves simulation of sediment deposition, grain rearrangement, mechanical compaction, chemical compaction (pressure solution as well as temperature dependent contact dissolution resulting from chemical corrosion), and growth of various cement types with various morphologies. Although the system was developed for clastic sedimentary rocks, we also have found it to be a useful tool for simulation of the evolution in fluid flow and geomechanical properties of evaporite rubble associated with the collapse of a chamber in a salt dome that is being used for nuclear waste disposal.

Fractures are the predominant flow pathways in low-permeability rocks. Understanding the fluid-rock interactions that occur in rock fractures and their effects on fracture aperture variations is important for assessing the sustainability of reservoir productivity. This study presents two long-term flow-through experiments with fractured pure quartz sandstones to investigate how fluid composition affects fracture changes over time. One sample was continuously flowed through with fluids (DI or Si-rich fluid), while the other sample was subjected to intermittent flow (DI) at certain time intervals. The results show that the hydraulic aperture of the sample with intermittent flow maintains relatively constant, and the pore fluid is enriched with Si that is higher than the corresponding quartz solubility. On the contrary, hydraulic aperture reduces by 50% of its initial value in the case of continuous flow. The pore fluid Si concentrations are far below the quartz solubility. Based on the microstructure variations of contact asperities and the fluid concentration changes, we demonstrate that pressure solution plays a dominant role in rock fracture deformation and permeability changes. The pore fluid composition has a remarkable effect on the permeability decay process. The cumulative Si in the pore fluid without flow would mitigate fracture closure by limiting pressure solution. In contrast, the continuous injection of DI would lead to the continuous mass transfer between the contact asperities and the pore fluid. The permeability evolutions in the two cases are likely governed by the Si precipitation process and the stress-driving dissolution process, respectively.

Clay cements can occur pervasively throughout larger volumes of sandstone, thereby affecting the reservoir properties significantly. They affect irreducible water content and pore surface roughness. Moreover, any induced fluid or heat flow, as a consequence of hydrocarbon and geothermal production or CO2 sequestration, may have unwanted effects because of the clay minerals present. The effects will be dependent on the mineralogy, texture and distribution of the clay minerals. Clay minerals replacing detrital components (feldspars and rock fragments) have limited effect because of their dispersed and isolated occurrence. In this study diagenesis of intragranular clay in siliciclastic sandstones is evaluated, using Rotliegend deposits in the Southern Permian Basin and Lower Triassic Buntsandstein deposits as examples. This study clearly shows that large-scale fluid flow does not play a significant role and that much of the mass involved in diagenesis is retained more or less in situ. In the sandstone proper, clay occurs in various ways: as detrital laminae and beds, as patches related to burrows, and as grain coatings through clay infiltration. In addition, clay occurs as cements rimming grains and replacing detrital feldspars and rock fragments. The apparent detrital clay is partly or largely modified during burial diagenesis and much of the clay is authigenic. Not only the mineralogy is changed but also the location and distribution of the authigenic clays. In conclusion: authigenic clays in reservoir sandstones, including clay rim cement, are genetically associated with and directly linked to infiltrated or bioturbated clay.

The clastic Lower Triassic Buntsandstein Formation in the Upper Rhine Graben of SW Germany and NE France has been identified as an attractive geothermal reservoir due to its fracture density and exceptionally high matrix porosity at depth levels of economic geothermal energy extraction. New petrophysical data from deep exploration wells reveal the existence of ternary porosity systems evolved during a multi-phase subsidence history and diagenesis especially at intra-graben structural highs. Primary elements of these porosity systems are high-permeability faults and fractures which can be utilized as technical fluid conduits connecting geothermal injectors and producers. Second component is the primary matrix porosity, controlled by pure mechanical compaction. Third component is an interconnected system of secondary pores and micropores. Secondary porosity originates from diagenetic dissolution of chemically and mechanically unstable framework grains like feldspars and rock fragments. At depths of about 2.300 m secondary porosity and microporosity can exceed the compaction-controlled primary porosity of around 7 %, causing high total pore volumes of up to 21 %. All matrix pore types are linked to form an interconnected pore network hosting significant connate brine volumes. These brine volumes don´t contribute to technical hydrogeothermal fluid cycling but increase the thermal capacity of the reservoir and favour heat conduction. Although this phenomenon has been described from hydrocarbon pools, their quantitative significance in geothermal reservoirs is still poorly understood. Micro-scale reservoir simulations may help to upgrade geothermal prospects.

Geochemical processes such as mineral dissolution and precipitation alter the microstructure of rocks, and thereby affect their hydraulic and mechanical behaviour. Quantifying and considering these property changes in reservoir simulations substantially supports risk assessments related to geological subsurface utilization.

In our virtual laboratory, 3D pore-scale models of typical reservoir sandstones are applied to determine the effective hydraulic and elastic properties of sandstones. In order to adequately depict characteristic distributions of secondary minerals, the virtual samples are systematically altered, and the resulting changes in geometric, hydraulic, and mechanical rock properties are quantified. Characteristic pore space alterations for a reaction- and a transport-limited precipitation regime are approximated by correlating precipitation with fluid flow velocity magnitudes. A purely surface reaction-limited regime is represented by a uniform modification of the pore space, whereas transport-limited precipitation is characterised by the successive clogging of pore throats and a drastic decrease in permeability. It is demonstrated that the location of mineral growth within the pore space strongly affects the magnitude of permeability reduction. The presented digital pore-scale simulations enable to quantify changes in permeability and stiffness resulting from geochemical processes, and thus are relevant for a wide range of natural and engineered subsurface applications.

The dynamics of subduction zones is linked to the rise and demise of forearc and backarc sedimentary basins in the overriding plate. Subsidence and uplift rates of these distinct basins are controlled by variations in plate convergence and subduction velocities and determined by the rheological and thermal structure of the lithosphere. In this study we conducted a series of high-resolution 2D numerical models of oceanic subduction and subsequent continental collision. The numerical code 2DELVIS involves erosion, sedimentation, and hydration processes. The models show the evolution of wedge-top basins overlying the accretionary wedge and retro-forearc basins in the continental overriding plate, separated by a forearc high. These forearc regions are affected by repeated compression and extension phases. Higher subsidence rates are recorded in the syncline structure of the retro-forearc basin when the slab dip angle is higher and the subduction interface is stronger. This implies the importance of the slab suction force as the main forcing factor creating up to 3-4 km negative residual topographic signals. Extensional back-arc basins are either localized along inherited weak zones at large distance from the forearc region or are initiated just above the hydrated mantle wedge. Back-arc subsidence is primarily governed by crustal and lithospheric thinning controlled by slab roll-back. Our results are compared with the evolution of the Mediterranean and we classify the Western and Eastern Alboran, Paola and Tyrrhenian, Transylvanian and Pannonian Basins to be genetically similar forearc–backarc basins, respectively.

Submarine lobes are high aspect ratio sand-rich deposits that are fed by turbidity currents and debris flows via channels in deep-marine settings. As a major component of submarine fans, they represent 1) an important archive of palaeo-environmental change, 2) sinks for organic carbon and pollutants, and 3) are also of economic interest. Classic models describe lobes as purely depositional tabular sheets that thin and fine from an apex. Over the last decade, outcrop studies, numerical and stochastic modelling, and flume tank experiments have been undertaken to constrain the hierarchy, geometries and stacking patterns of submarine lobe deposits and test these simple models for lobe deposition.

With this talk I want to give an insight into the discoveries made and new understanding gained about lobe deposits, including: 1) The variety of lobe fringe deposits depending on the level of confinement experienced by the lobe: Distinguishing frontal and lateral lobe fringes enables more accurate reconstructions of the geometry, distribution, and orientation of deep-water lobes, whereas the recognition of aggradational lobe fringes enables the reconstruction of subtle intrabasinal relief. 2) Boundary conditions governing lobe dimensions: lobe dimensions, and their relation to their feeder channels, vary with basin-floor angle, and the concentration of sediment within the feeding gravity-current. Discharge rate is also important, controlling when deposition starts. Because these parameters change during evolution of natural deepwater systems, lobes formed at different times will have different geometries.

Permian deposits are found in outcrops and in the subsurface of Central Tunisia. Their sedimentary and stratigraphic characteristics and origin are not fully understood and represents the main focus of this work. Base level changes, location of the palaeo-coastline and stratigraphic architecture and sandstone connectivity of formations are insufficiently known. Answering these questions will impact future hydrocarbon exploration and improve the geological understanding of Tunisia.

Seismic lines and well data of the Jeffara Basin have been re-interpreted and seismic data converted to depth domain. The results indicate a shallow marine rimmed shelf depositional environment, with dimensions of 100 square kilometers and a general east-west orientation. Seventy kilometers to the north of the reconstructed paleoshore line twelve stacked reef complexes up to 3000 meters thick were identified. Literature study of the area indicates a tropical climate. Structurally, it was observed that the Permian is not affected by major normal faults and appears at large scale gently folded. Wells and outcrop investigations provide lithological information, which is composed of limestone and dolomite, with intervals of sand and shale. The thickness gradually increases northwards, reaching 4000 meter maximum.

Using DionisosFlow, 3D stratigraphic models are constructed. They provide a number of equiprobable scenarios of facies distribution through the basin matching the available data. This modelling approach highlighted the impact of base level changes on reef geometry and in the lateral connectivity of clastic deposits. It also indicates depocenters shifting, shoreline evolution and feeder systems position and importance over time.

The distribution of rocks and rock properties is an important part of an overall strategy for reservoir development, placement of new wells and prediction of future production. It also provides a detailed look into the local development of a sedimentary basin. Here we present a case-study from the “Atled Creek” concession, onshore Nigeria. A 3D structural reservoir model of the concession was prepared from available industry seismic data and well logs. Four sandstone reservoirs within the Cenozoic have been identified in the “Atled Creek” and modelled in this study to highlight variations in the reservoir properties. Four available wells were subjected to conventional well log analyses and reservoir units were mapped on the 3D seismic volume. The resulting facies and property logs were upscaled and together with the interpreted seismic horizons and faults formed the input data for facies and property modelling. This resulted in frameworks of 3D facies, petrophysical and fault models. The fault model revealed the dominance of generally W–E trending faults. A major fault trending WNW –ESE (F1) separates the reservoirs into two major blocks with the existing well located in the southern block. Fault assisted anticlinal closure is likely the prominent trapping mechanism revealed by the structural model. The reservoir model classified the reservoirs as moderate to good with total porosity of 23.8 – 34.7% in reservoir unit A, 6.3 – 33.1% in reservoir unit B,3.1 – 42.8% in reservoir unit C and 6.4 – 41.7% in reservoir unit D.

The sedimentary succession of the Helmstedt Lignite Mining District at Schöningen in northern Germany includes the upper Paleocene to lower Eocene Schöningen Formation and the middle Eocene Helmstedt Formation. It covers the entire Paleogene greenhouse phase including the long-term Early Eocene Climatic Optimum (EECO) and short-term events such as the Paleocene-Eocene Thermal Maximum (PETM/ETM1) and its gentle demise almost continuously in an estuarine situation at the southern edge of the proto-North Sea. Due to the interaction between changes in sea level, salt withdrawal in the subsurface and climate-related changes in runoff from the hinterland the area was subject to frequent changes between marine and terrestrial conditions, repeatedly leading to peat formation. A new robust stratigraphic framework for the succession is based on a combination of biostratigraphy, eustatic sea-level changes and carbon isotope data.

The more than 200 m thick succession with 13 up to 15 m thick lignites offers a rare opportunity to study Paleocene–Eocene near-coastal ecosystems and to trace the effects of long- and short-term climate change on the diversity and composition of the plant communities across 10 million years during the Paleogene greenhouse. As far as known, the estuarine succession at Schöningen is worldwide unique with respect to duration and continuity. The aim of an ongoing project is to study the response of the vegetation in this paralic environment to climate change by applying pollen and spores as proxies.

Melt inclusions in zircon (MIZ) directly reflect the physicochemical state of the magma during zircon growth. However, their potential as geothermometers and petrogenetic indicators is still poorly explored. Therefore, we investigated MIZ from well-characterized mafic and felsic rocks of the Bushveld Complex (South Africa) and acquired a novel dataset of major, trace and volatile element contents. Re-homogenized MIZ of all rock types display rhyolitic compositions (65-78 wt% SiO₂) and similar H₂O contents (1.6-4.0 wt%). Liquidus temperatures of MIZ obtained from normative Qz-Ab-Or and rhyolite-MELTS modelling indicate melt entrapment at 930–850°C (at 200 MPa), tailing down to 700°C in some samples. For rutile-bearing mafic cumulates of the lower BC (Marginal and Critical Zone), these temperatures overlap with TiO₂ saturation temperatures of MIZ as well as with Ti-in-zircon of host crystals using aTiO₂=aSiO₂=1.0 [1], in accordance with textural associations of zircon+rutile+quartz. In contrast, MIZ in all rutile-free, magnetite-ilmenite-titanite- and quartz-bearing rocks of the upper BC (Upper Zone ferrogabbros, granitic rocks), display strikingly lower Ti contents, but also higher ƩREE and lower Th/U. Cross-calibration of TiO₂ saturation (MIZ) and Ti-in-zircon thermometers with MIZ liquidus temperatures suggests that zircon crystallized at highly reduced aTiO₂~0.3, significantly below aTiO₂~0.6 previously estimated for rutile-free rocks in the literature, usage of which would underestimate zircon crystallization temperatures by 50-100 °C. In summary, MIZ may inherit chemical signatures of host rocks, are powerful zircon geothermometers and provide constraints for aTiO₂ in Rt-free rocks.

[1] Ferry & Watson (2007) CMP 154, 429–437; [2] Hayden & Watson (2007) EPSL 258, 561-568

Zircons of magmatic rocks can show enormous variations in Th/U ratios (0.2 to 100) and extreme Th/U zoning. We present data from felsic and mafic rocks of the Bushveld Complex in South Africa. Zircon grains in mafic cumulate rocks reveal Th/U ratios up to 70, those in felsic rocks barely exceed 1.0. In mafic rocks zircon mostly occur together with Rt-Bt-Kfs-Qtz in intercumulus domains, and crystallized during final magma cooling between 900 and 700°C, after >75% of fractional crystallization. The resulting zircons reveal very distinct Th/U zoning trends. Group (1) zircons show systematic increase in Th/U from core to rim (from 0.5 to 20), accompanied by a systematic decrease in U content (from >170 to 10 ppm), group (2) zircons the opposite trend, and group (3) zircons nearly no zoning. Modelling result reveal that all three zoning trends can be explained by minor differences in Bt-Rt-Zrc crystallization history. Trend (1) results from Rayleigh-like fractionation due to zircon growth (±Rt), having different partition coefficients for U ≫ Th. Trend (2) results from zircon growth after onset of biotite-in reaction, causing breakdown of previously formed rutile, thereby releasing U≫Th. Trend (3) results from mass balance constrains, causing mutual compensation of fractionation effects. The absence of pronounced Th/U zoning of zircons in felsic Bushveld rocks also results from compensation of zircon fractionation due to coeval crystallization of abundant rock-forming minerals (Opx-Cpx-Hbl-Pl-Kfs-Qtz) at an early stage of fractional crystallization (10-20%), all being highly incompatible for Th and U [1]. [1] Gudelius et al. (2020). Chemical Geology 546, 119647.

Determining the tectonic evolution and thermal structure of a tectonic unit that experiences a subduction-related pressure temperature (P-T) loop is challenging. Within a single unit, P-T conditions can vary from top to bottom which can be only revealed by detailed petrological work. We present micropetrological data of the middle section of the Cycladic Blueschist Unit (CBU) in Naxos, Greece, which indicate a different P-T loop than the top of the section.

In the middle section, strong deformation associated with high-T metamorphism erases most of the earlier tectonometamorphic imprints preventing to apply "traditional" geothermobarometry methods. Using Zr-in-rutile and Ti-in-biotite thermometry coupled with quartz-in-garnet elastic barometry and phase equilibrium thermodynamic modeling, we identify a prograde path from ~15.4 kbar to ~19.9 kbar and from ~496 °C to ~572 °C, equilibration during decompression at ~8.3 kbar and ~519 °C followed by near-isobaric heating to ~9.2 kbar and ~550 °C (or even ~584 °C), and a final greenschist-facies equilibration stage at ~3.8 kbar and ~520 °C.

We compare these P-T estimates with published data from the top of the CBU section and find that the bottom half of the CBU on Naxos records higher peak high-pressure (HP) of about 4 kbar than the top, defining the thickness of the CBU to about 15 km in the Eocene. We determine that crustal thickening of up to ~15% occurs in the upper half of the CBU section during exhumation of the HP rocks in an extrusion wedge during convergence.

We present eclogites and garnet pyroxenites from Danmarkshavn (Greenlandic Caledonides). So far, one ultra-high pressure (UHP) location has been described from NE Greenland. There, thermobarometry yielded conditions of 972 ºC/36 kbar (Gilotti and Ravna, 2002).

Eclogites from Danmarkshavn show spectacular exsolution of Qtz from Cpx, which is known from UHP assemblages. The sample most suitable for unraveling precise conditions, however, is a garnet pyroxenite containing abundant Cpx and Opx, some Grt, minor accessory minerals as well as little retrograde Am and Pl. Opx and Cpx preserve high-pressure compositions in cores of large crystals and extremely low Al-content in Opx clearly indicate UHP conditions. A considerable portion of these minerals, however, reequilibrated during exhumation with especially Cpx showing complex retrograde zoning. We infer that Grt grains completely reequilibrated during net-transfer reactions producing Am and Pl.

Precise conditions in such rocks are often achieved by intersection of isopleths, e.g. Al-in-Opx with Grt-Cpx-Mg-Fe thermometry. Both isopleth sets have positive slopes in pressure-temperature space. If exhumation occurs along a trajectory steeper than the thermometer isopleth, equilibration of Mg-Fe-exchange during exhumation leads to possibly dramatic overestimation of peak conditions. In our sample, this yields up to 1000 ºC/>40 kbar. Based on Cpx and Opx core compositions alone, however, we infer considerably lower peak conditions of 800-830 ºC/30-32 kbar.

We find that micro-xrf scans of whole thin sections yield powerful data on mineral zoning, reaction progress and the degree of reequlibration. Such maps allow better defining targets for high-resolution mapping and high-precision microprobe work.

Geological models, as 3-D representations of subsurface structures, can be combined with gravity inversions to obtain geometric representations of geological objects with similar porperty distributions. These models are built on prior assumptions and imperfect information, and they often result from an integration of geological and geophysical data types with varying quality. These aspects result in uncertainties about the predicted subsurface structures and property distributions, which will affect the subsequent decision process.

We discuss approaches to evaluate uncertainties in geological models and to integrate geological and geophysical potential-field information in combined workflows. A first step is the consideration of uncertainties in prior model parameters on the basis of uncertainty propagation (forward uncertainty quantification). When applied to structural geological models with discrete classes, these methods result in a class probability for each point in space, often represented in tessellated grid cells.

A logical extension is the integration of geological forward operators into geophysical inverse frameworks, to enable a full flow of inference for a wider range of relevant parameters. We investigate here specifically the use of probabilistic machine learning tools in combination with geological and geophysical gravity and magnetic modeling. Challenges exist due to the hierarchical nature of the probabilistic models, but modern sampling strategies allow for efficient sampling in these complex settings. We showcase the application with examples combining geological modeling and geophysical potential field measurements in an integrated model for improved decision making.

The inversion of gravity data for crustal thicknesses is a nonunique problem. Therefore, additional independent information (e.g., seismic data) is needed to constrain the inversion process. Despite decades of exploration efforts related to mining and the installation of more seismic stations, knowledge on the deep crustal structure of southern Africa remains limited.

In this contribution we present a crustal thickness model for southern Africa: The initial model is determined by inversion of satellite gravity data. Here, we apply seismically constrained non-linear inversion, based on the modified Bott's method and Tikhonov regularization assuming spherical Earth approximation. The inversion hyper-parameters are determined by Monte-Carlo-Marcov-Chain (MCMC) simulation. The data quality of the (active and passive) seismic constraints is high in general, showing e.g. individual uncertainties per point. The problem is that the constraining data points are irregularly distributed, resulting in large areas without constraints. Therefore, in a next step, we want to validate and improve the modelling result for these unconstrained regions.

We use the initial constraining data set to geostatistically simulate a homogeneous crustal thickness model for the investigation region. For this, we apply a Sequential Gaussian Simulation (SGS) based on Ordinary Kriging that includes the uncertainties of the seismic data and allows to characterize uncertainties of the simulated points. The simulated crustal thickness model is then used to qualitatively validate the inversion result. Additionally, we redo the inversion process with a new constraining data set that combines the preexisting constraining points and the simulated model.

When Western Gondwana broke apart into the South American and African continents ⁓ 120 Ma ago, some of its cratons were broken apart as well. Following the isopycnic hypothesis, their long-term stability and often neutral to positive buoyancy can be explained by the counteracting effects of cooling (density increase) and iron depletion (density decrease). To separate these effects, we created the presented models following an iterative integrated approach using mainly seismic and gravity data. In the first step, seismic models of Depth to the Moho were created to allow correction of the gravity field and calculation of the residual topography. Second, based on mineral physics and S-wave tomography, we assessed temperature variations in the uppermost mantle and subtracted their effects from both residual gravity and topography. Afterwards, a joint inversion enables determination of potential compositional variations. Adapting the initially juvenile mantle composition leads to a change of thermal effects, thus the process was repeated iteratively until convergence. In result, we obtained self-consistent models of temperature, thermal and compositional density variations, and #Mg, a measure of iron depletion. Our results show deep depleted cratonic roots under the Amazonas, São Francisco, Paranapanema (South America), West African, Northern to Central Congo and Zimbabwe Cratons (Africa). Depletion appears to be mostly absent in the Rio de la Plata Craton of South America and its proposed African counterpart, the Southern Congo Craton as well as the Kaapvaal Craton below 100 km depth and the Tanzania and Uganda Cratons.

3D geological modelling in highly complex areas with sparse or ambiguous information is affected be conceptual uncertainty, which can be significantly reduced by the integration of gravity data. However, gravity modelling itself underlies the non-uniqueness problem, indicating that there is more than one model consistent with the observed gravity field. Therefore, cross-validation of gravity models by integration of regional geologic concepts, geometric and kinematic construction and restoration techniques helps solving this problem.

In this regard, we defined an integrated modelling strategy, which starts with extracting a-priori information from geological maps, 2D seismics, borehole and gravity data, which were independently analysed and conservatively interpreted; i.e. non-unique solutions were completely avoided. Subsequently, geologic interpretations were combined with gravity data, which was analysed by use of gradient calculation and 2D-EULER deconvolution. The resulting combined dataset was validated by use of 2D cross-section balancing techniques considering bed-lengths and area consistency. The resulting serial balanced cross-sections served as solid basis for a 3D gravity modelling.

Our integrated workflow was tested for the less-explored eastern part of the Subhercynian Basin (Saxony-Anhalt, Central Germany). We show that the combination of independently ambiguous data holds the potential to generate new insights into the local fault system, the topography of the crystalline basement (transition of the Mid-German Crystalline Rise and Rhenohercynian Zone) and outlines of salt structures as well as the setting of the base Cenozoic. Furthermore, modelling of long wavelength gravity anomalies provides new information on the crustal setting at the margins of the North German Basin.

With this study we revise and improve the three-dimensional lithospheric-scale structural and density model of Germany (3-D-D). Major shortcomings of this model resulted from joining three regional 3-D models that were poorly covered by data at their margins. Merging into a larger model revealed structural inconsistencies in these “marginal” domains. In order to resolve discrepancies between the units in a more consistent way we integrate newly available data from seismic reprocessing, tomography, and use 3-D gravity modelling to improve the fit between the modelled and observed gravity.

The recently initiated reprocessing of the DEKORP seismic profiles, for example, in the region of the Rhine Graben by the federal geological survey of Hesse (Bär et al. in prep.), indicate that previous assumptions on sediment thickness in certain regions, as well crustal structure and Moho depth need to be revised. We integrate this new structural information together with density variations derived from mantle seismic tomography (CSEM Europe, Fichtner et al., 2018; LSP_Eucrust1.0, Lu et al. 2018) and analyse the updated density distribution against the more detailed Bouguer gravity anomaly map of Germany (Skiba, 2011).

The update of the 3-D-D model is important for ongoing research in seismic hazard assessment in that it serves as a basis for thermal and rheological modelling helping to relate observed seismicity with spatial variations in strength. The model provides a data-consistent background for regional studies on sustainable use of geothermal energy and on the suitability of sites for the underground storage of radioactive waste or of CO2.

Tuwaiq Mountain Escarpment in the Central Saudi Arabia exposes the Late Jurassic carbonates, which are one of the world’s most prolific oil-producing strata in the subsurface. The outcrops provide a window of opportunity to study the architecture of these strata that is found usually complex due to heterogeneous lateral and vertical facies. These heterogeneities are sub-seismic in scale, thus, the information from outcrops bridge the gap between seismic and core data. This virtual field trip focuses on the Late Jurassic Hanifa Formation outcrops at Wadi Birk, central Saudi Arabia with an objective to highlight and display interwell scale heterogeneities associated with depositional architecture. The Hanifa Fm is one of the major hydrocarbon reservoirs in the subsurface of Saudi Arabia and is also in many respects analogous to the even more prolific overlying Arab D reservoirs.

The virtual field trip will include a 4x4 km² 3D digital outcrop model (DOM). The VRGS (Virtual Geoscience) platform will be used to run this field trip. The participants will be taken to one of the most spectacular exposures of the Hanifa Formation at Wadi Birk in Central Saudi Arabia. Depositional facies (in outcrop and thin section), 3D Digital Outcrop Models, and geophysical (GPR, Seismic) and petrophysical datasets (Spectral Gamma Ray - SGR) will be discussed. The main learning outcome of this field trip is to show reservoir equivalent facies in the outcrops but also provide clues into the intricacies of the stratal architecture. It will be demonstrated that the layered architecture is actually not so layered (as usually observed and published). Depositional cycles will be defined based on geological, geophysical, and petrophysical datasets (measured sections, core, thin section, and SGR). The mapping of the depositional cycles within the 4x4 km² area at Wadi Birk will aid in demonstrating that vertically and laterally the depocenters (sediment production) were migrating. These depocenters are a product of high sediment production by the buildups (stromatoporoid/coral), and relatively low sediment production or current winnowing in the inter-buildups areas. Further, the variability in the shape and sizes of the stromatoporoid/coral build-ups laterally adds more complexity to the thickness of a depositional cycle and provides clues to environmental dynamics. Uneven topography is healed during the deposition of the next cycle with the areas of higher accommodation availability becoming natural depocenters.

The observations and results will be used as input into high-resolution static reservoir models to address the gap of our understanding in inter-well scale heterogeneities of similar subsurface hydrocarbon reservoirs.

The Wren's Nest National Nature Reserve, situated in the West Midlands, UK, is well known for its exposures of Silurian (Wenlock and Ludlow Series) carbonates. The Wren’s Nest was first recognised as a nature reserve in 1965, and in 2020 it became recognised as part of the part of the Black Country Unesco Geopark. The area has significant geological importance due to the superb preservation of its fossils, with more than 700 macro fossil species identified (including brachiopods, bivalves,corals, crinoids, trilobites, gastropods, cephalopods and bryozoans), and is particularly well known for the trilobite Calymene blumenbachii, locally known as the “Dudley Bug”.

The Wren’s Nest Hill forms a large elongated N-S anticlinal dome structure faulted along is main axis by the Wrens Nest Fault, with the structure forming in the Late Carboniferous as a result of the Variscan Orogeny.

The nature reserve also has an extensive industrial heritage with the limestone being mined since the 1700’s for building stones, lime, fertilizer and during the industrial revolution as a flux for iron smelting, with abundant coal being available locally from the surrounding coal measures. An extensive network of mines and tunnels exists, with Dark Cavern being the largest man-made cavern in the UK. These mines are linked together by a series of underground canals which in turn join the national canal network.

With the underground workings closed off to the public for safety reasons this field tour is constructed using surface data only and attempts to reconstruct as much as possible through information from the archives.

The geodynamics in the Central Alps during the Miocene were majorly characterized by the exhumation of crystalline basement, the so-called external crystalline massifs. Their exhumation had a major impact on the evolution of relief, distribution of drainage networks and sediment-generation. The timing of their first surficial exposure and their total thickness still remains debated. The Swiss Molasse Basin contains ~35 to 13 Ma old clastic deposits that were mostly derived from the immediate hinterland and contain valuable information about its tectonic and climatic evolution.

For this thesis, this sedimentary archive is used to trace the exhumation of the external crystalline massifs. In particular detrital garnet geochemistry is used to investigate 21.8 to 15 Ma old alluvial fan deposits of three different fan systems of the Swiss Molasse Basin. In this context, unusually grossular- and spessartine-rich garnets supplied from greenschist-facies metamorphic granitoid rocks serve as a unique proxy for the sediment supply from the external crystalline massifs. Their first appearance in a 15 Ma old sample in the Napf Fan indicates an at least partial exposure to the surface at that time. These garnets can neither be found in the alluvial fans to the east nor to the west, suggesting a relatively stable N/NW-directed drainage system since Miocene times. Another species of extremely grossular-rich garnets of so far unknown provenance has been found in 16.5-17 Ma sandstone of the Napf Fan, indicating a highly dynamic hinterland evolution during the Miocene, which is contrasting previous findings based on more traditional provenance proxies.

The first step in any provenance study is sampling the sediment of interest, which is subject to many potential sources of error. It is nevertheless commonly assumed that one sample of sediment is enough to provide a somewhat “basin-averaged” compositional signal. Spatial or temporal variability of this signal is often not considered.

In this study, we test the temporal variability of sediment composition in modern fluvial deposits in four German rivers: the Gersprenz, Modau and Mümling in the Odenwald, and the Neckar close to the city of Tübingen. We revisited the same locations 12 times in the course of one year to take a sample. The samples were analyzed for grain size distribution (GSD) and geochemistry via XRF measurement.

The results show that

(1) the four river sediments have overall different GSD, which could be related to their different source lithologies;

(2) there are variabilities in the GSD of samples taken in different months, and these can be correlated with flood events;

(3) the bulk geochemistry changes significantly between months;

(4) within narrow grain size windows (1Φ-steps), the chemical composition varies less than the bulk geochemistry.

We conclude that bulk geochemistry of fluvial sediment varies mostly as a result of varying GSD, and not due to actual provenance changes throughout the year. On the one hand, this is promising for studies that assume fluvial sediment to faithfully reflect a “basin-averaged” provenance signal. On the other hand, it shows that geochemical data should always be interpreted in tandem with GSD.

The paleogeographic position of the Alpine terrane with respect to (peri-) Gondwana during the Paleozoic is still a matter of debate. In this study we use a multi-proxy approach to analyze the provenance of siliciclastic sedimentary rocks from the Carnic Alps and the Northern Greywacke Zone, which include detrital U-Pb zircon dating, petrology and bulk geochemistry. The biostratigraphically well constrained deposits from the Carnic Alps have been used as a reference profile, and these results were compared to samples from the monotonous sediment record of the Northern Greywacke Zone. The stratigraphic interval ranges from the Middle Ordovician to the Silurian.

The petrological and geochemical data indicate a high compositional maturity, which is supported by ZTR-dominated heavy mineral spectra. The results of U-Pb zircon dating (in total 957 concordant ages) show signatures typical for sedimentary rocks from the margin of Northern Gondwana and can be assigned to the East African-Arabian province. Most of the zircons show Pan-African ages, but presence of Meso- to Palaeoproterozoic and few Archean ages point to contributions from central Gondwana. Cambro-Ordovician zircon ages are linked to local volcanism at the northern margin of Gondwana. A stratigraphic trend both in the Carnic Alps and the Greywacke Zone is characterized by an increase of zircons with Tonian ages (900-700 Ma) and a decrease of zircons with Pan-African ages (700-550 Ma).

We interpret the shift in detrital zircon ages by enhanced sediment input from the center of Gondwana mainland and reduced input by detritus from Cadomian crust of Northern Gondwana.

Evolutionary stages, from late Eocene to Miocene, of Pindos foreland, mark the transition from Pindos oceanic basin, in the east, to Gavrovo carbonate platform sedimentation in the west. Pindos Thrust as a crustal-scale structural element resulted in the formation of the Pindos foreland. Current research, which is based on detailed field campaign and on cross-sections, correlates and interprets the tectonic evolution of the area. The study area is part of the external Hellenides and belongs to the eastern Pindos foreland (SE Aitoloakarnania region). Pindos foreland consists of a syn-orogenic sedimentary succession with thick clastic deposits where compressional deformation acted synchronously to sedimentation. The activation of NNW elongated Gavrovo and Ionian Thrusts modified and controlled the syn-orogenic evolution of the area. In particular, the study area is characterized by the formation of fault-related fold structures of Gavrovo Thrust, such as the Varasova and Klokova anticlines and the Vassiliki syncline. Westwards propagating thrusting deformation has been partitioned by dextral strike-slip faults like Evinos Fault. This dextral strike-slip fault acts as a pathway to Evinos River flow. Finally, the syn- to late-orogenic evolution of the area is modified by normal faulting, forming the current geotectonic framework of the area.

Acknowledgments

This work was funded by the H.F.R.I. (Hellenic Foundation for Research and Innovation) and GSRI (General Secretarial for Research and Innovation) through the research project "Global climate and sea-level changes across the Latest Eocene-Early Oligocene, as reflected in the sedimentary record of Pindos foreland and Thrace basin, Greece, 80591".

Turbidites are the main reservoir rocks in many sedimentary basins. Through well log profiles and using stratigraphy of high-resolution sequences, 6 stratigraphic surfaces of 3 and 4 order were interpreted. These surfaces were defined trough facies association (cores) and petrofacies (thin sections). Each surface has an electrical signature and a seismic amplitude. Correlating wells and mapping the seismic lines, the 2D and 3D stratigraphic surfaces are then obtained. With Schlumberger's Petrel a seismic and stratigraphic verification points were defined. Then the 3D structural model was built by the faults and zones of the top and bottom layers. For this area, a Grid with 50X50m cell size (horizontal limit) was defined. Following this, the pillar gridding and the layering are generated. For facies modeling, a facies profile was obtained in the stratigraphic sections trough the correlation between logs and rock. A good log and seismic signature can separate the reservoirs (sandstones), from the source rock (shale) and carbonates. Histograms are necessary to define the accuracy and representativeness of the model, defining the vertical modeling limit. To complete the model, it is necessary after the study with histograms, the scale up of the model and if necessary, insert a trend (a paleocurrent for example). The most representative interpolation method for this model was SIS Modeling (Sequential Indicator Simulation). The result was considered satisfactory and correlated with the profiles of existing wells, indicating a methodology to be used constantly by the industry. This serves the O&G sector, geothermal energy and groundwater exploration.

Apatite is a pivotal mineral in carbonate rocks, because it can incorporate all of the major magmatic volatile species (H, P, F, S, Cl), as well as REE and HFSE into its structure. To quantify the effects of fractional crystallization of apatite crystals on the (H, P, F, S, Cl) volatiles and metal budget in the residue melt, the partition coefficients of a broad range of elements (F, Cl, S, REE, HFSE, Co, Ni, Sr, Mo, Ba, W, Pb, Th and U) between apatite and carbonatite melts were determined at 800 °C and 200 MPa using internally heated pressure vessels. The experimental results show that the partition coefficients of Sr, Y and REE (D) are in the range 2-10, and the partition coefficients of Sc, Mn, Fe, Co, Ni, Mo, W, U and HFSE are <<1. The effects of volatiles and oxygen fugacity on the partition coefficients are insignificant. This study defines the apatite-melt partition coefficients for the halogens: D_F= 0.68-1.76; D_Cl=0.10-0.19; and D_S= 0.016-0.05. The P₂O₅ solubility in carbonatite melt decreases from 6.8 to 1.4 wt% in ‘dry’ carbonate to volatile (H₂O, F, Cl and S)-bearing carbonate. The results suggest that apatite is preferred to be saturated in hydrous carbonate, and thus cumulated apatite sequester more REE from the residue melts. Finally, we will show that the experimentally determined partition coefficients make apatite a potential indicator for the volatile and trace element abundances in carbonatite magmas.

There is a large amount of downhole logging data gathered for scientific and commercial purposes, but studies applying time series analysis and cyclostratigraphy are not abundant. Especially the fast availability of logging data makes it valuable, also for decisions on which cores to investigate first. Here, we summarize the specific properties of downhole logging data most relevant for time series analysis and cyclostratigraphy. As for data from core- or outcrop analysis, it is important to be aware of both the potential and also possible issues of data. For logging data challenges, include changing borehole diameter, influences of drilling fluids and the fact that logged data may be a composite record. This contribution tries to give a concise summary of chances and possible challenges.

The late early to early middle Eocene (~48 Ma) maar lake sediments of the famous Messel fossil-pit, located near Darmstadt, SW Germany, represent a prime archive for climate dynamics operating during the geologically most recent greenhouse period of the Earth. In this study, we investigate the potential of geochemical data obtained via high-resolution XRF core scanning to decipher hydrologic variability from the Messel sediments. Such data have the potential to yield insight into the paleoenvironmental and paleoclimatic evolution of Messel in unprecedented temporal resolution. As such, they may provide further help towards understanding potential climatic impact on evolutionary patterns as revealed by the fossil record. Our preliminary results from the research drill core of 2001 show a robust correlation with available data on the vegetation from the pollen and spore record and hence hint at the great potential of using XRF core scanning as a tool to decipher wet-dry variability during the early and middle Eocene on orbital to interannual time scales.

Lithium is an important compound in several industrial applications and is mostly found in lithium ion batteries (LIBs), ceramics and glass. Lithium deposits are hosted in pegmatites, sedimentary rocks and brines (i.e., salt lakes, salars, oilfield brines, and geothermal brines) comprising 25 - 26 %, 8 % and 59 - 66% of the world’s Li resources, respectively. Geothermal brines in the Upper Rhine Graben, Germany, with Li concentrations of up to 200 mg/L and resources of 2.7 Mt Li₂CO₃ represent potentially economically mineable Li deposits. The scope of our project is to extract Li from these high saline (i.e., TDS ~100 - 200 g/L) geothermal brines by sorption using natural and synthetic zeolite and clay minerals. These high saline brines are slightly acidic in pH and characterized by high concentrations of major cations (e.g., Na⁺ up to 60 g/L, K⁺ up to 4 g/L, Ca²⁺ up to 11 g/L and Mg²⁺ up to 1.9 g/L) and anions (e.g., Cl^- up to 120 g/L and SO₄^2- up to 1.5 g/L). Synthetic zeolite 13X and natural clinoptilolite-mordenite-montmorillonite mixtures have been used for preliminary sorption experiments. We performed batch sorption experiments with synthetic Li-solutions and variable concentrations and temperatures between 25 – 60 °C. Furthermore, we studied the effect of competing ions (e.g., Na⁺) on Li-sorption. Thereby, we investigate the different materials for sorption capacity and kinetics, chemical stability, structural effects of Li incorporation and their applicability to geothermal brines.

Geoscientific studies in Antarctica are extremely challenging due to the remote location of the continent, its harsh environment and difficult logistics. Additionally, the continental crust is covered by an up to 5 km thick ice sheet, which makes surface based geoscientific studies extremely difficult. Gravity field measurements and gravity based subsurface models are therefore essential in studying the structure, properties and processes of the Antarctic subsurface.

In the last decades a large database of airborne, shipborne and ground based gravity data has been compiled. Recently, all existing and new gravity data were processed to infer an enhanced gravity field solution for Antarctica.

Subsequently, this new gravity field solution can be used for further geophysical studies. We use gravity disturbances to study subglacial topography, sediment thickness and Moho depths to improve respective existing models in Antarctica.

Studying these parameters on a continental scale, we apply 2D Parker-Oldenburg inversion in combination with results from other gravity based studies and further constraining data.

Additionally, we make use of the higher resolution of the new gravity grid (5 km) to study smaller regions in more detail, specifically the Weddell Sea area and Queen Mary Land. Here, we use gravity forward modelling constrained with ice penetrating radar and seismic data to infer geometric structure and densities of the subsurface.

In this contribution we present results of the Parker-Oldenburg Inversion and discuss the underlying parameters. Also, we show the resulting 3D forward models of the Weddell Sea area and Queen Mary Land.

Sicily is a part of the central-Western Mediterranean area and represents a geotectonic boundary between the African and European plates. It is the result of a complex geological process based on a polyphasic evolution of a compressional step beginning with the Oligocene-Miocene clockwise rotation of Corsica-Sardinia simultaneously with the extensional processes of the Tyrrhenian basin. Consequently, the area is constrained by the continuing partial advance of the Sicilian-Maghrebian chain southwards and the Tyrrhenian extensional area towards the internal foreland areas (Hyblean domain). The study focuses on the creation of a 3D lithospheric-scale model of a 300 km x 400 km extended area in the central Mediterranean domain (Lat38°, Lat35°), which is consistent with the available geological and geophysical data, as well as with the observed gravity field. The reconstructed (simplified) geological setting consists of a lithospheric mantle, a crystalline basement (continental and oceanic crust), carbonates, the European margin and the Neogene-quaternary cover including volcanic bodies. The work aims to investigate the geometry of lithosphere integrating tomographic models in order to assess the major density contrasts and the lithospheric thermo-mechanical state. The regional 3D model provides also the boundary conditions for local thermal models to investigate afterwards.

The Ligurian Sea in the western Mediterranean Sea is a back arc basin created through the Apennines Calabrian subduction zone between 30 and 15 Ma ago. The inner geological structure of this basin is not well known. To improve the knowledge about the density distribution of the crust and lithosphere, we performed a pre-processing of gravity data prior to 3D-modelling. This work is related to research in the MB-4D priority and AlpArray project.

The satellite gravity gradients from GOCE were directly interpreted and used for filtering of different wavelengths to calculate residual fields, Bouguer and Free-Air anomalies as well as invariants and Euler-Deconvolutions. Furthermore, seismic profiles from several ship-borne surveys as well as OBS measurements of the AlpArray project (LOBSTER, GEOMAR, Kiel) and bathymetry data contributed additional information.

The processed data show an unknown anomaly offshore Marseille and the possibility of several underground structures with different densities. The basin itself is characterized by a mass surplus and positive anomalies with a maximum between Corsica and north-west Italia, while the anomalies underneath Corsica and Sardinia are neutral to negative.

The derived information will be used in the 3D-modelling software IGMAS+ to execute an inversion for the area and create a model of the mass distribution beneath the Ligurian Sea and its margins.

The Bohemian Massif represents the largest exposure of rocks deformed during the Variscan orogeny. Western Carpathians form an arc-shaped mountain range related to the Alpine orogeny. In our study, the lithospheric structure of the key tectonic units in the area and their contact zone was analyzed by 2D gravity modelling along the NW-SE oriented CEL09 profile of the CELEBRATION 2000 seismic experiment. New gravity map compiled at the initiative of the AlpArray Gravity Research Group was used. This map is based on a uniform reprocessing of the national terrestrial gravimetric databases of ten countries of the wider Alpine region. The resultant 2D density model based on gravity data was constrainted by results of seismic reflection and refraction method. Applied densities were defined by transformation of the modelled P-wave velocities. A good correlation between the density and seismic models was shown. The resultant 2D density model consisting of five principal layers (sediments, upper crust, lower crust, lower lithosphere and asthenosphere) shows differences between the older, cooler and thicker Bohemian Massif (in average: ~32 km thick crust, and ~120 km thick lithosphere), and the younger, warmer and thinner Carpathian-Pannonian region (~28 km crust, ~95 km lithosphere). The detected contact is delimited by a change in the Moho and the LAB topography, and assumes an overthrusting of the Western Carpathians onto the Bohemian Massif by ~30 km resulting in a neo-transformation of the crust/mantle and related lithosphere after subduction.

Underground storage of hydrogen could be an alternative way to store large amounts of energy. However, microbial consumption of H₂ is still a major uncertainty factor. Since microbial life is widespread in the crust of the earth an underground storage site needs to be seen as a habitat for microorganisms. Microbial activity at the H₂ storage site might affect the stored H₂ as well as the integrity of the storage site itself.
There is great need for more information about microbial H₂ transformation activity at conditions relevant for underground H₂ storage i.e. elevated pressure, high temperature and about potential geochemical interactions with surrounding fluid and rock material.
In this study, different fluids from potential subsurface storage sites representing storage in salt caverns or porous rock reservoirs were investigated. While some fluids were inactive, long lasting hydrogen consumption was observed by a porous rock reservoir fluid. Microbial H₂ oxidation tolerated high pressure as well as pressure and temperature fluctuations reflecting cycles of H₂ storage. In this fluid microbial H₂ consumption was shown to be sulfate dependent and led to the formation of sulfide. Furthermore, an increase of sulfate reducing bacteria during microbial H₂ consumption was identified by high-throughput sequencing of 16S rDNA. These results indicated the oxidation of H₂ by sulfat reducing bacteria to be the presumed process in this porous rock reservoir fluid. Due to the heterogeneity of the investigated fluids, microbial H₂ oxidation activity at different H₂ underground storage sites cannot be generalized but requires site specific investigations.

The save and effective storage of hydrogen in geological formations is an important part towards the implementation of renewable energy use. Due to fluctuating power supply from wind or solar plants, it is envisaged to use excess energy for electrolytical hydrogen production and the subsequent temporary storage in geological formations, as buffer for energy at “high-demand-low-production-times”.

The preferred geological storage formations are either salt deposits or porous sandstones with a gas-tight caprock. To date, these formations are generally confirmed to be appropriate for natural gas storage. However, the deviant physical properties of hydrogen, in terms of density, viscosity and hence mobility, require a reassessment of migration characteristics in these rocks.

For this purpose, an experimental set-up was designed, constructed and tested to quantify hydrogen migration rates in rocks. It comprises two gas chambers, separated by a through flange, containing the epoxy-embedded sample section with an exposed area of 7 cm². The retentate chamber is filled with a gas mixture of 2 Vol% hydrogen in synthetic air at 0.1 MPa. The permeate chamber contains air and includes an amperometric hydrogen sensor. Since there is no pressure gradient, the driving force for hydrogen movement is solely the concentration gradient between both sides of the rock sample. The hydrogen break-through and transport rates are monitored. In initial tests, core pieces of various length of sandstone and salt at dry and wet conditions are employed. The results approve the functional capability of the set-up and allow for a first-approach characterisation of hydrogen gas transport.

Hydrogen is a prospective energy carrier whose storage in extensive volumes is still an unsolved problem. One approach is underground hydrogen storage, in which geological formations such as salt caverns or depleted natural gas and oil reservoirs are used to hold large amounts of gas under pressure. However, in those formations minerals can react with the hydrogen stored and therefore deplete or contaminate the gas recovered.

In our previous project we have shown that various minerals (e.g. pyrite, smectite, hematite) reacted with hydrogen under storage conditions (~120°C, <100 bar). Especially the Fe³⁺/Fe²⁺ switch in a reaction in which hematite is reduced to magnetite forming water (3 Fe₂O₃ + H₂ → 2 Fe₃O₄ + H₂O) was found to be active. Mechanistic data of that reduction is abundantly available at high temperatures (>500°C). However, studies at storage conditions (45-120°C) are rare up to this point. Especially the influence of pressure is unclear.

The work presented aims to understand the processes by which hematite is reduced under those conditions. For that purpose, we built a system in which we measure the decreasing hydrogen concentration periodically. Is consists of a heated pressure vessel on whose outlet a 10-port-valve flushes a gas-sample to a mass spectrometer. The resulting H₂-peaks in the MS-spectra are quantified using Ne as internal standard. This way we are able to obtain time-resolved data on the consumption of H₂ as well as formation of H₂O by hematite. Additionally we quantify the hematite to magnetite ratio using XRD after the experiment.

NASA's Mars Science Laboratory mission, with its Curiosity rover, has been exploring Gale crater since 2012 with the goal of assessing its potential to support life. The mission has compiled compelling evidence that the crater basin accumulated sediment transported by marginal rivers into lakes that likely persisted for millions of years in the early Hesperian. Fluids simultaneously circulated in the subsurface and likely existed through the dry phases of lake bed exposure and eolian deposition creating a continuously habitable deep biosphere environment that persisted of millions to even hundreds of millions of years, conceivably even into early Amazonian time. Geochemical and mineralogical assessments indicate that ancient environmental conditions would have been suitable for sustaining life, if it ever were present. A diversity of organic molecules has been preserved, though degraded, with evidence for more complex precursors. In situ studies of modern wind-driven sediment transport and multiple large and active aeolian deposits have led to advances in physical theory of boundary conditions and bedform development. Despite 9 years of exploration, rover systems and science instruments remain healthy and capable of performing all key scientific objectives.

In the last decade, lithium has become a European strategic metal due to its extensive consumption in electromobility and green technologies. Consequently, global demand has increased substantially encouraging European interest in assessing its own resources, identifying a potential Li-industry and securing its own supply. In this context, a geographically-based compilation of the European lithium from both: 1) hard-rock, and 2) deep fluids occurrences and ore deposits, with their corresponding features (e.g., deposit types, Li-bearing minerals, Li content, host-rocks) have been assessed.

Accordingly, it appears that lithium is not particularly rare and is relatively well represented and distributed within Europe. Indeed, regarding lithium hard-rock resources, about 527 occurrences including 30 deposits have been identified mostly related to endogenous processes such as lithium-cesium-tantalum (LCT) pegmatites, rare-metal granites and greisen mineralization. Wheareas, about 182 occurrences of Li-bearing geothermal fluids from which Li content is above 15 mg/l has also been identified.

It appears that Li is significantly enriched in two distinct geodynamical contexts: 1) late orogenic process, related to a continent-continent collision for endogenous processes; and 2) local crustal thickening, as well as post-orogenic extensional setting for the exogenous processes. Thus, the complementarity of these two studies has been demonstrated that Li-bearing geothermal brines are coeval with emplacement of Li-magmatic bodies (LCT pegmatites and granites) as well as emplacement of large sedimentary basins in Europe suggesting an extensional setting as observed for Li-rock hard-rock deposits.

As a leading industrial country, Germany has a great need for metallic raw materials, which will even increase over the next years with the intended energy and mobility transition.

To meet the demand for metallic raw materials, the industry in Germany is heavily dependent on imports from abroad. To reduce this dependency on imports, Germany is working towards a circular economy in which resource efficiency and the recycling of metals play a prominent role. However, a circular economy will only be able to cover a portion of the necessary raw material requirements. Therefore, the import of primary raw materials will continue to be of decisive importance in the future.

The sourcing of the raw materials, however, must be responsible in order to avoid human rights violations and environmental impacts in the metals supply chains.

Human right violations can nowadays be managed quite well in metals supply chains through laws and guidelines. But so far there are no adequate instruments to address environmental risks in metals supply chains. Despite this lack of instruments, the EU is considering to enact a supply chain regulation which could make manufacturers liable for environmental impacts in countries where the metals are produced.

To facilitate the assessment of environmental risks in metals supply chains, a hands-on screening tool to recognize and red flag environmental risks in such supply chains using the example of battery metals is presented.

Since metals are often used in alloyed forms, proper management and efficient recycling of metal scrap is key to sustainable management of those alloying metals as well. Previous studies on the trade of metals and metal containing products focused mainly on the carrying major metals themselves, however, the quantity and type of their embodied alloying elements remain rarely investigated. In this paper, we aim to address this knowledge gap by compiling an alloying element composition database for scrap of three bulk metals (iron and steel, aluminum, and copper), and using Denmark, a typical industrialized country with a high share of metal scrap export, as an example. Our results show that most alloying elements embodied in bulk metal scrap exported from Denmark depict a fluctuating yet overall increasing pattern from 1988 to 2017. Denmark’s metal scrap exported almost only to European countries, and Germany and Sweden are two largest receivers. While alloying elements embodied in steel scrap such as chromium and nickel and the construction sector contribute the most to the total embodied alloying elements, other alloying elements such as cobalt, bismuth, vanadium, titanium, and niobium with a lower amount yet a high market value and criticality status deserve a closer look as well. We conclude that further investigation on how the trade of metal scrap affect the recycling pathways and efficiencies of alloying elements are needed to support discussion on global and regional resource management and circular economy strategies.

To reach Germany’s climate neutrality goal in 2045, different technological and systematical changes have to be conducted, such as the expansion of renewable energies plants, the shift towards e-mobility and the necessary infrastructure. For the measures, metallic raw materials will be increasingly required. The German government plans to support those industry sectors, which are emitting great amounts of CO₂. The data evaluation on emissions and energy consumption in Germany shows that the sector "production and first processing of iron and steel" is the second largest emitter of CO₂ in Germany, with around 40 million tons of CO₂ per year. On the one hand, steel is essential for the construction of renewable energy plants and, on the other hand, its production accounts for appr. 5 % of total German CO₂ emissions. Consequently, steel production is part of the solution and the challenge of the climate neutrality goal. Various options to decrease industrial CO₂ emissions in Germany are being discussed, as e.g. the use of hydrogen. To produce green hydrogen, various metallic raw materials are required for the production of green energy plants and electrolyzers. The amount of the metallic raw materials is calculated specifically for the application of hydrogen in the German steel production in 2030.

The underground storage will play an important role in the energy transition, both for energy storage as for CCS. Current storage activities in the Netherlands are for natural gas, diesel oil and nitrogen are in both in depleted gas reservoirs and salt caverns. These probably will be extended in the near future with storage of CO₂, hydrogen and compressed air.

The Dutch State Supervision of Mines is the regulator who oversees that these activities are performed in such a way that they are safe, now and in the future. This means that the full life cycle has to be considered with a broad perspective on the safety of people and the environment.

The predictions of behaviour of the storage and its fluids and related risk will have large uncertainties due to the level of uncertainty in the subsurface data used, and the limited amount of data to calibrate the models which calculate the risk. In most cases this will mean that the risk can’t be calculated probabilistically. In that case for decision making it is necessary to not only investigate the most likely scenario, but to the range of realistic, possible scenarios to identify the real risk. The period after storage will be orders magnitudes longer than the storage activity itself. This will lead to even larger uncertainties for this phase.

We have to face the fact that we can only partly reduce this uncertainty by further research and monitoring. However research and monitoring can help us to quantify the uncertainty. This emphasizes the importance that operators, policy makers and regulators are able to handle the uncertainties in their decisions before, during and after the storage activities, and communicate openly about them.

Re-using of large-volume salt caverns for the intermediate storage of liquid and gaseous energy carriers is an indispensable step on the way to a sustainable energy economy. Continuous development of methods for monitoring these facilities is a crucial part of the social license to operate. In the research project "Monitoring system for the safety of cavern storage facilities using satellite and unmanned aerial system (UAS) data" (KaMonSys), safety solutions for critical infrastructures are implemented in an interdisciplinary approach of remote sensing and geoscientific methods. Using underground storage facilities (USF) as an example, multisensory approaches are being developed to monitor the facilities as well as their surroundings by satellite and UAS-based monitoring to detect possible emissions, such as methane, hydrogen and carbon dioxide.

The coupling of classical geological methods of subsurface assessment with innovative approaches from remote sensing shows a huge potential for further research. Although KaMonSys will initially be developed for a cavern storage facility, which have considerable relevance for the "in time" gas supply of Germany, the final process will also be applicable to other industries as a safety solution for secondary markets.

This presentation describes the initial evaluation of available spatial data (INSPIRE and associated project partners Uniper and Salzgewinnungsgesellschaft Westfalen) on the surface/Subsurface situation, the integrated development of a 3D geoinformation system (GIS) to evaluate data and its usage for the development of 3D UAS flight plans.

The project is supported by federal funds within the German BMBF funding framework "Research for Civil Security" (FKZ 13N15366).

The transition from nuclear and fossil energy to renewable energy leads to higher fluctuations in energy supply – but storage for power is negligible so far. In underground gas storages (UGS) huge amounts of TWh can be stored to meet the demand consistently. However, this results in increasing injection and extraction frequencies, leading to faster pressure and stress changes and therefore posing additional challenges for reservoir rock, cap rock and technical components.

To evaluate the effects of additional cyclic loading on the rock-cement-steel-compound of the UGS infrastructure, we use an autoclave system on a realistic scale. Mainly abandoned drillings are simulated, the system therefore consists of a 2 m long cemented steel casing with an autoclave chamber at each end and surrounding heating mats. To simulate injection and extraction, gas pressure (N₂) is applied and released on both ends. Additionally, temperature can be raised to 100 °C. Between loading cycles, permeability can be measured to determine the effect of pressure and temperature variation on the tightness of the system.

We present results from the analysis of three cemented casings. Since the hardened cement isn’t connected to the steel casing after experiments, we assume an annular gap as main gas path. This gap is modelled and fitted to the experimental data. After pressure variations between 0 bar and 60 bar, tightness of the system decreased in every experiment, which leads to an increased modelled annular gap width. Temperature variations between 30 °C and 70 °C tend to increased tightness slightly.

Untertage-Gasspeicherung stellt eine wesentliche Nutzung des Untergrunds dar. Sie trägt insbesondere zur Stabilität der Energieversorgung bei. Auch in Zukunft kommt der geologischen Kurz- und Langzeitspeicherung stofflicher Energieträger eine große Rolle zu.

Obwohl die Gasspeicherung in Salzkavernen Stand der Technik ist, haben sich die Betreiberanforderungen dahin gehend geändert, dass neben den saisonalen Gasumschlägen zunehmend auch kurzfristige hoch-frequente Speicherzyklen aufgrund veränderter Speichermarktanforderungen gefahren werden. Insbesondere aufgrund der thermo-mechanischen Wechselwirkung beim Ein- und Ausspeichern von Gas resultieren daraus grundlegend neue Fragen zur Betriebssicherheit, d. h. Integrität der geologischen Barriere Salz sowie der technischen Installation des Bohrloch-Casings im Kontakt mit der Bohrlochzementierung sowie dem Salzgebirge.

Unter der Zielstellung einer qualifizierten Bewertung potentieller Risiken bei den verschiedenen Varianten des modernen Speicherbetriebes wurde durch das IfG im Rahmen des BMBF-Forschungsvorhabens SUBI eine umfassende Studie zu den verschiedenen Aspekten durchgeführt.

Ausgehend von einer umfassenden Literaturstudie zum nationalen und internationalen Stand der Fluidspeicherung in Kavernen in Salzgesteinen wurden die aktuellen technischen Konzepte dargestellt und stattgefundene technische Havarien ausgewertet. Die daraus resultierende Arbeitsthese ist, dass bei den in der Literatur beschriebenen Havarien kein integrales Versagen der Salzbarriere stattfand, sondern generell technische (z.B. schlechte Zementation) oder geologisch/geomechanische Bohrloch-Casing-Probleme (z.B. Strukturrandlage, ungünstige Salzbedingungen, Überlagerungen im komplexen Kavernenfeld) ursächlich waren.

Zur Verifizierung dieser Thesen wurden sowohl experimentelle Untersuchungen an natürlichen Salzgroßproben und Bohrlochzement als auch modelltechnische Arbeiten zur Modellierung von zyklisch überprägten saisonalen Belastungen bei der Gasspeicherung in Salzkavernen durchgeführt.

The assessment of the long-term stability of geological units in the context of subsurface use is a complex topic in which various geoscientific and technical aspects play an important role. For example, the geomechanical stability of radioactive waste repositories due to endogenous, exogenous and engineering processes is an important aspect in the long term. For a stability prognosis, an estimation of the recent stress state as well as an assessment of realistic future stress changes is required. However, data on the current stress state in the upper crust are incomplete, sparse and spatially unevenly distributed. Therefore, geomechanical-numerical models are the only possibility to estimate the complete stress tensor at locations where stress observations are not available.

The SpannEnD project, had the goal to estimate the 3-D stress state in Germany. Therefore, a simplified subsurface model was created. Since stress data are essential for the calibration procedure, the first open access database for stress orientations as well as stress magnitudes was developed, which mainly summarises data from the study region. The best-fit stress model is assigned to the model which reproduces the results of many of the available magnitudes of horizontal stresses well. In the model region, there are numerous large-scale faults or fault systems that have an influence on the local stress state. However, the large number of faults could not be implemented as structural features in the geomechanical model. However, the modelled stresses are applied on the fault geometries to assess the fault reactivation potential.

The overall amount of metals and their variety used for technical applications has been subject to a steep increase during the past decades and is forecast to further develop. Growing metal demand for a wide range of high technology applications, including so-called ‘green’ technologies (e.g. PGM, REEs, Te) drives the economic value of these metals and the related mining efforts. For some of these metals, anthropogenic metal fluxes have outcompeted natural biogeochemical cycles, including plate tectonics (Sen & Peucker-Ehrenbrink, 2012). Dispersion and loss, inherent to their cycle between production and use (e.g. PGM from automobile catalytic converters), limit their overall recycling rates and/or end-of-life recovery is uncertain as collection and recycling still need development (e.g. REE, Yang et al. 2017). Their presence in all environmental compartments, including remote areas, makes these metals emerging contaminants and warrants systematic surveillance. However, the geochemical backgrounds, often at ultra-trace levels, and anthropogenic contributions of the critical elements are still widely under-documented, as many analytical challenges persist. Studying exposure and effects in complex environmental matrices, including natural waters or biota, at environmentally relevant contamination levels, is a prerequisite to the assessment of exposure risks.

References

Sen, I.S., Peucker-Ehrenbrink, B., 2012. Anthropogenic disturbance of element cycles at the Earth’s surface. Environ. Sci. Technol. 46, 8601–8609. https://doi.org/10.1021/es301261x

Yang, Y., Walton, A., Sheridan, R. et al. REE Recovery from End-of-Life NdFeB Permanent Magnet Scrap: A Critical Review. J. Sustain. Metall. 3, 122–149 (2017). https://doi.org/10.1007/s40831-016-0090-4

Siderophores are important biogenic chelators produced by plants, microbes and fungi, which promote the (bio-)availability of iron and other highly-charged cations in the natural environment. The hydroxamate siderophore desferrioxamine B (DFO-B) enhances the mobilization of certain trace elements that hydrolyze easily and hence are traditionally assumed as being ‘immobile’ during water-rock interaction. Leaching of different rock material with DFO-B under ambient conditions, for example, facilitates the formation of a very pronounced positive Ce anomaly in bulk-normalized patterns and fractionates the Th-U element pair, which we tentatively attributed to an oxidation of Ce(III) to Ce(IV) and U(IV) to U(VI). We here reports results of an investigation into the effects of solution pH, fO₂ and weathering state of different rocks on the mobilization of redox-sensitive trace elements and their isotopes during water-rock interaction in presence of DFO-B. The impact of natural organic ligands on redox-sensitive elements may be largely underestimated. Siderophores are omnipresent today and may also have been present in the geological past. Our preliminary results indicate that the impact of solution pH on fractionation of redox-sensitive trace elements is rather small, but that fractionation is strongly controlled by oxygen fugacity and by the weathering state of the studied rock. Siderophores have the potential to significantly catalyze the oxidation of these elements even under strongly hypoxic conditions.

Rare Earths and Yttrium (REY) have become pivotal constituents of many high-technology products and processes. Their widespread use has led to a growing release of (“anthropogenic”) REY into the environment and hence rising concerns about their (bio)geochemical and (eco)toxicological behaviour. Yet, information on REY transfer, fractionation and bioaccumulation and -magnification in the food web is still scant.

Here, we present REY data for naturally grown duckweeds and ambient waters. Duckweeds are small, rapidly-growing macrophytes inhabiting many lentic water bodies worldwide. Duckweed is increasingly used as protein-rich animal feed and food supplement for vegans. The REY concentrations of duckweeds are in the µg/kg range (dry matter) and exceed those of ambient waters by several orders of magnitude, revealing strong bioaccumulation. Their shale-normalised (_SN) REY patterns are rather flat and show little variation regardless of sampling site and season. By contrast, the REY_SN patterns of all 0.2 µm-filtered water samples are characterised by an increase from light REY (LREY) to heavy REY (HREY) and some show large anthropogenic positive Gd_SN anomalies. Such anomalies have become common in Germany and can be attributed to the application of Gd-based contrast agents (Gd-CAs) in magnetic resonance imaging. The absence of anomalous Gd enrichment in all duckweed samples suggests that Gd-CAs are not incorporated by these macrophytes but corroborates their conservative behaviour in the environment. Moreover, partition coefficients between duckweeds and ambient waters show that the duckweeds preferentially incorporate LREY over HREY, possibly due to stronger complexation of HREY with dissolved ligands.

Rare Earths and Yttrium (REY) are widely used in many domains, resulting in anthropogenic input into the environment. However, still little is known about their uptake and bioavailability towards aquatic organisms.

We studied REY bioavailability by quantifying their concentrations in the aragonitic shells of Corbicula fluminea, which are precipitated from the extrapallial fluid (EPF) of the mussel. Both shells and ambient water samples were collected from the Elbe and Weser rivers which are known to carry anthropogenic gadolinium (Gd) from Gd-based contrast agents (Gd-CAs) applied in magnetic resonance imaging. The shells were grouped according to their size, meticulously cleaned, acid-digested and pre-concentrated before ICP-MS measurement. Analytical quality was monitored by using REY-poor reference material JLs-1.

Total REY concentrations in the shells decrease with increasing shell size, indicating that REY uptake occurred most rapidly during the juvenile age of mussels. Shale-normalized REY patterns show a continuous increase from light REY (LREY) to heavy REY (HREY) and a slightly inverse V-shape for shells from the Elbe and Weser rivers, respectively. Compared with the 0.2 µm-filtered waters from the same locations, the shells show between 2 to 4 magnitudes higher total REY concentrations. Despite significant anthropogenic Gd enrichment in the river waters, no Gd anomaly is observed in the shells suggesting long environmental half-life and poor bioavailability of the Gd-CAs. Partition coefficients between shells and water reveal a preferential uptake of LREY over HREY in mussel shells. These observations complement and corroborate the results of previous research on shells from the Rhine River.

Uranium (U) isotopes are suggested to monitor the success of (bio)remediation relying on the reduction of soluble and mobile U(VI) to less soluble U(IV)¹. However, the subsurface stability of U(IV), typically present as solid-phase non-crystalline U, may be affected by complexation or oxidation. Understanding these processes and their impact on U isotope fractionation is important to correctly interpret field U isotope signatures.

We investigated U mobilization by complexation and oxidation and measured the associated U isotope fractionation in laboratory batch experiments. Non-crystalline U(IV) was produced as the starting material by reducing a U(VI) isotope standard with Shewanella oneidensis MR-1². Subsequently, U(IV) was mobilized: 1) anoxically, with ligands (EDTA, citrate, or bicarbonate), 2) by oxidation with Fe(III), or 3) with molecular oxygen at low pH in the presence of the bacterium Acidithiobacillus ferrooxidans.

All ligands mobilized U(IV) and enriched ²³⁸U in the complexed fraction (δ²³⁸U: 0.2 to 0.6 ‰). Oxidative U mobilization both, with Fe(III) or with At. ferrooxidans biomass, resulted in insignificant U isotope fractionation. Either isotope fractionation during all involved reaction steps was very small or cancelled eachother out. The latter may be indicated by the observation of high aqueous δ²³⁸U values (~0.8 ‰) in corresponding abiotic control experiments (without biomass), which may be the result of adsorption effects after oxidative U mobilization.

(1) Bopp et. al. Environ. Sci. Technol. 2010, 44 (15), 5927–5933.

(2) Stylo et al. Environ. Sci. Technol. 2013, 47 (21), 12351–12358.

The Icelandic mantle plume is probably the largest convective upwelling on Earth. It is generally agreed that its growth and evolution have had a significant influence on the geologic and oceanographic evolution of both the North Atlantic Ocean and Northwest Europe during Cenozoic times. At the present day, three significant observations testify to the existence and size of this plume.

First, residual depth anomalies prevail in the oceanic lithosphere surrounding Iceland. These anomalies show that the oceanic plates are 1-2 km shallower than expected in a region that stretches from Baffin Bay to the coast of Norway, and from Svalbard to Newfoundland.

Secondly, an irregular-shaped long wavelength free-air gravity anomaly with an amplitude of 30-50 mGal is centred upon Iceland.

Thirdly, full-waveform tomographic imaging of the North Atlantic region shows that the planform of the Icelandic plume has a complex irregular shape with significant shear wave velocity anomalies lying beneath the lithospheric plates at a depth of 100-200 km. Distribution of these anomalies suggests that about five horizontal fingers extend radially beneath the fringing continental margins. The best-imaged fingers lie beneath the British Isles and beneath western Norway where significant departures from crustal isostatic equilibrium have been measured. It has been suggested that these radial fingers are generated by a phenomenon known as the Saffman-Taylor instability. Experimental and theoretical analyses show that fingering occurs when a less viscous fluid is injected into a more viscous fluid. For radial, miscible fingering, the wavelength and number of fingers are controlled by the mobility ratio (i.e. the ratio of viscosities), by the Péclet number (i.e. the ratio of advective and diffusive transport rates), and by the thickness of the horizontal layer into which fluid is injected. Shear wave velocity estimates have been combined with residual depth measurements around the Atlantic margins to estimate the planform distribution of temperature and viscosity within a horizontal asthenospheric layer beneath the lithospheric plates. These calculations yield mobility ratios, Péclet numbers, and asthenospheric channel thicknesses that are compatible with Saffman-Taylor fingering. A useful rule of thumb is that the wavelength of fingering is ~5 times the thickness of the horizontal layer. Across the Northwest European shelf, the pattern of mapped residual topography and subsidence anomalies is remarkably consistent with the planform of asthenospheric fingering. In conclusion, a combination of disparate observations supports the notion that Cenozoic dynamic topography of Northwest Europe is generated by fast, irregular horizontal flow within thin, but rapidly evolving, asthenospheric fingers of the Icelandic plume.

Widespread exhumation and uplift affected Central Europe in Late Cretaceous to Paleogene time (e.g. Kley and Voigt, 2008, Geology, 36, 839-842). The area involved includes thrust-related basement uplifts and inverted Mesozoic basins and extends at least from the Rhenish Massif to the Bohemian Massif and from the Black Forest/Vosges to the North German Basin. Exhumation and basin inversion started at approx. 95 Ma based on stratigraphic constraints (Voigt et al. 2021, Solid Earth, https://se.copernicus.org/preprints/se-2020-188), well in line with ZHe cooling data (e.g. von Eynatten et al. 2019, International Journal of Earth Sciences, 108, 2097-2111). Late Cretaceous SW-NE directed basement thrusting (e.g. Harz Mountains, Thuringian Forest, Flechtingen High) peaked around 85 to 70 Ma. Thermochronological data (AFT, AHe) from the Triassic uplands between the basement highs reveal km-scale exhumation of a wider region, at least 250-300 km across, suggesting long-wavelength domal uplift (von Eynatten et al. 2021, Solid Earth, 12, 935-958). This domal uplift is dated slightly later at 75 to 55 Ma and calls for a separate mechanism superimposed on the Late Cretaceous compressional event. Based on timing, spatial extent of the doming area and thickness of eroded strata (3-4 km), possible mechanisms are evaluated for their contribution to exhumation and uplift. While shortening and crustal thickening may explain 50% of the domal uplift at most, upwelling asthenosphere driving dynamic topography appears capable of producing uplift and erosion of the required magnitude, wavelength and rate.

East European Craton (EEC) in Poland has been recently studied by onshore PolandSPAN and offshore BalTec regional seismic surveys. PolandSPAN data imaged earliest Late Jurassic, earliest Late Cretaceous and mid-Late Cretaceous laterally extensive unconformities that document hitherto unknown substantial uplifts of the SW edge of the EEC. Cretaceous unconformities might have been formed as a result of inversion-induced buckling of the cratonic edge. BalTec offshore survey was acquired within the transition zone between the Paleozoic Platform and EEC. SW part of BalTec data imaged offshore segment of the Mid-Polish Swell formed due to inversion of the axial part of the Polish Basin. NE from the MPS, within the Bornholm–Darłowo Fault Zone, system of Late Cretaceous strike-slip syn-depositional faults was documented. E part of the BalTec survey is located above the EEC basement overlain by Cambro-Silurian sedimentary cover that is dissected by a system of steep, mostly reverse faults, regarded so far as having been formed as a result of the Caledonian orogeny. BalTec seismic data proved that at least some of these deeply-rooted faults were active as a reverse faults in latest Cretaceous. This suggests that large Paleozoic blocks might have been uplifted during the widespread Late Cretaceous inversion. Erosion of these blocks might have provided sediments that formed Upper Cretaceous progradational wedges within the onshore Baltic Basin imaged by PolandSPAN data.

This study was funded by NCN grants UMO-2017/27/B/ST10/02316 and UMO-2015/17/B/ST10/03411. ION Geophysical is thanked for providing PolandSPAN seismic data, and Kingdom IHS for providing seismic interpretation software.

The Phanerozoic lithosphere in Central Europe was formed due to the Caledonian and Variscan Orogenies. It then probably underwent modification and thinning associated with widespread and intense Permian volcanism. Since the Permian, the evolution of the Central Europe lithosphere is characterized by various phases of moderate extension and inversion tectonics caused by external forces. Sedimentation and intra-plate volcanism yield evidence for additional intra-plate processes related to variable lithsopheric thickness and deformation. Whereas its crustal structure has been extensively studied by Deep Seismic Soundings, properties of the subcontinental mantle lithosphere including its thickness are less well known. Surface waves are well suited to study the lithosphere and the sub-lithospheric structure, being mainly sensitive to the S-wave velocity structure at those depths. Here we present results of high-resolution surface-wave tomography, down to ~250 km depth, from automated broad-band inter-station Rayleigh phase velocities. The thickness of Central Europe lithosphere shows a remarkable variability. Thick lithosphere is found beneath the Paris Basin, whereas the lithosphere in the area of the North German Basin and the Bohemian Massive shows moderate thickness. Thinner lithosphere is found in the area of the Cenozoic intra-plate volcanism. Comparison to the distribution of Permian and Jurassic volcanic rocks provides evidence for a time variable thickness of the continental lithosphere in Central Europe. We relate subsidence and sedimentation without substantial extension to lithospheric cooling and thickening. In contrast, uplift and volcanism without compression indicate thermal thinning of the lithosphere. Conceptual models for the lithopsheric evolution in the area are discussed.

Coastal regions represent a transition between land and sea. From the hydro(geo)logical point of view freshwater and saltwater are coming together here. The groundwater discharge which discharges directly into the sea is called submarine groundwater discharge (SGD). At the regional scale, SGD is often measured indirectly based on tracers. At the local scale, SGD flux over time can be measured directly, e.g. using seepage meters. However, this method only represents the punctual source of discharge. Especially to record the diffusive discharge locations, a new method which focuses on the puddles in intertidal areas as potential diffusive discharge locations was developed. There, the salinity and water depth were observed at different puddle locations over time. Moreover, photos were taken in order to get information about the changing area of the puddle. From these data we calculated a water budget to show how much submarine groundwater discharges at the measured puddle. The results show a geographically and temporal variability of the SGD in the mudflat of the south of Königshafen on Sylt. The diffusive discharge locations were primarily located at the beginning of the intertidal zone. In order to support the new method, two additional pore water measurements were conducted at each puddle. The salinity of the pore waters were freshening with increasing depth here. The presented method can help to transfer the observed data of SGD to a regional scale.

Detailed process-understanding of climatic and non-climatic drivers is generally required to estimate future groundwater availability under climate change. Groundwater level (GWL) dynamics are very sensitive to groundwater pumping, but information on their local effects and magnitude – especially in combination with natural fluctuations – is often missing or inaccurate. It has been shown by previous studies that complex hydrogeological processes can be learned from neural networks, whereby Deep Learning (DL) demonstrates its strengths particularly in combination with large data sets. However, there are limitations in the interpretability of the predictions and the transferability with such methods. Furthermore, most groundwater data are not yet ready for data-driven applications. This study aims at improving GWL predictions with DL by combining big data elements from a newly constructed global groundwater database with long-term short-term memory (LSTM) networks. Our underlying hypothesis is that scale-dependent processes can be learned for groundwater dynamics, similar to streamflow data. For our experiments we use continuous groundwater level observations from basins worldwide and basin attributes – spatially heterogeneous but temporally static catchment attributes (e.g. topography) and continuous observations of the meteorological forcing (precipitation and temperature). The initial results are consistent with previous studies in that GWL prediction performance is good with LSTM models trained with climate input on single wells. It is now being tested whether the LSTM model trained on many wells simultaneously is able to represent the climatic effects - but not the anthropogenic effects, e.g. with wells that are considered to be anthropogenically unaffected.

Saline contaminants from potash mining endanger aquatic ecosystems. Uncovered potash tailings piles release high amounts of chloride and sodium. Conventional coverage systems with a transpiration-intensive vegetation on a soil layer reduce percolation water only to some extent and does not protect the surrounding environment sufficiently. Powerful sealing layers are used to cover other mining deposits, but are still uncommon for potash tailings piles. In this paper, I study how to complement conventional coverage with additional sealings to minimize the release of contaminants effectively. I investigate a yet uncovered potash tailings pile in Germany. I model water balance parameters and calculate percolation rates for 44 different coverage systems. The results show that sealings always outperforms (max. 24.8 % of P) conventional coverage without an additional sealing (26.5 % of P). Site-specific coverage reduces percolation water more than uniform coverage and requires less layer material. A sealing works best on slopes with a northern orientation, soil cover systems perform better on southern slopes. I conclude that site-specific coverage systems are most effective to improve water quality in post-mining landscapes.

With the recently announced climate neutrality for the year 2060, there are plenty of questions in China about the future and the existence of the hard coal mining industry. With an annual production of 4 billion tons of hard coal, China remains the biggest producer of this resource. The consequences for the environment are tremendous. Climate neutrality poses new challenges for this country with its abundance of resources: hard coal is still the easiest and safest way to guarantee the supply of energy to its citizens, whereby energy security is a high priority. The switch to and the integration of renewable energies has already started and, according to the latest 14th five-year plan, should become the main driver of growth in the coming years. The transition to green development with a low carbon economy as one of the most important objectives is imminent. These developments will have a decisive impact on the next few years and will drive structural change forward. Since China also has large reserves of rare earths, which are required in particular for the construction of regenerative energy options. But here, too, only one environmental problem is shifted to the next, since the recycling of rare earths has not yet been developed and the sustainability factor is a big question mark. What impact this will have in terms of sustainability and environmental protection is identified in the research project.

The Enguri Dam in NW Georgia is one of the highest arch dams in the world. The 15 km power tunnel was initially flooded in 1978. During the rehabilitation project from January - April 2021, an 40 m long open construction-joint was observed. The construction-joints are located on both sides in the lower third of the tunnel, but only the construction-joint on the valley side showed an opening character.

The research question of the paper was whether the preferential opening of this joint can be explained by rock stresses.

The approach is based on the comparison of a numerical calculation of the stress-state with the observed cracks (recorded in April 2021) in the tunnel section at km 13.7, using a static, linear elastic 2D model with homogeneous material (limestone) with a variable FE-mesh. The initial stress-state is created via a lateral shortening at the valley side of the model in combination with gravitation.

The results show a symmetrical distribution of tensile and compressive stresses around the power tunnel, with the axis of symmetry tilted by about 30°. This results in tangential tensile stresses on the downslope side in the region of the construction-joint, while compressive stresses are expected in the section of the upslope construction-joint.

It has been shown that the initial stress-state is an important parameter for the positioning and design of the power tunnel. Furthermore, the topography can result in tilting of the stress field, which must be considered in the interpretation of observed fractures in the tunnel.

Smectites are widely used in (geo-) technical applications and are important components of soils. A definition gap exists between the uncharged non-swellable pyrophyllite and talc (ξ = 0) and the low charged swellable clay minerals (smectites) with 0.2 ≤ ξ ≤ 0.6. Furthermore, no reliable measurement method exists for ξ < 0.2. A recent theoretical study on the hydration of smectites (Emmerich et al. 2018) based on the density functional theory (DFT) indicates the existence of stable dioctahedral 2:1 layer silicates with ξ < 0.2 and substitutions either in the tetrahedral or octahedral sheet that are swellable. Therefore, our focus is to synthesize low charged smectites.

The Na₂O-MgO-Al₂O₃-SiO₂-H₂O system was reacted for triocthedral smectite synthesis at 200℃, for 72 h, and with stoichiometric composition corresponding to ideal layer charge of 0.18. The XRD results showed that the synthesis of trioctahedral smectite was successful with a small particle size. Particle size will be confirmed by AFM measurements. The CEC indicates a low charge in the envisaged range. According to the principle of AAM method (Lagaly. 1981), under ideal assumptions, when the layer charge value is less than 0.2, the long-chain alkylammonium ions will only form a monolayer structure (basal spacing <17.7 Å) after being intercalated into the smectite layer, which can also be proved by measuring the d001 value of synthetic smectite. Similar results obtained through our experiments.

References:

Emmerich et al. (2018) The Journal of Physical Chemistry C 122, 7484−7493.

Lagaly. (1981) Clay Minerals. 16, 1-21.

In the end of 2020, an approx. 650 m deep core was drilled at Prees in Shropshire, England, as part of the ICDP project JET (Integrated Understanding of the Early Jurassic Earth System and Timescale). The main objective of this project is to obtain and characterize a complete and continuous sedimentary archive of the 25 million years of the Early Jurassic. The Early Jurassic period (200-175 million years) was a period of extreme environmental changes: Rapid transitions from cold or ice ages to super-greenhouse events have been documented, including global changes in sea level and organic carbon distribution, as well as mass extinctions.

Knowledge of this part of the Earth's history is supposed to serve as an analogue for present and future environmental changes. The project will provide a "master record" for an integrated stratigraphy (bio-, cyclo-, chemo- and magnetostratigraphy) of this period. In addition, the project will allow the reconstruction of the local and global palaeoenvironment and the driving mechanisms and feedbacks responsible for environmental changes in the Early Jurassic.

The analysis of geophysical borehole measurements contributes to interpretations with respect to the lithological characterization of sediments and their boundaries, but also allows the description of sedimentary cycles related to orbital parameters, insolation and therefore to paleoclimatic history.

First results of these borehole measurements include a lithological classification which is based on cluster analysis of solely physical data. Furthermore, core-log integration has been carried out and a first attempt towards astrochronology and cyclostratigraphy has been made.

Understanding the evolution of lower latitude climate from the most recent glacial periods to post-glacial warmth in the continental tropical regions has been obstructed by a lack of continuous geological records. Here we present results from a lacustrine record from tropical North America. Specifically, we examine sediments from Lake Chalco, located in the Valley of Mexico, central Mexico (19°30’N, 99°W). The basin represents a hydrological closed system surrounded by the Trans-Mexican Volcanic Belt aging from the Oligocene to the present. We used borehole logging data to conduct a cyclostratigraphic analysis of the Lake Chalco sediments. More than 400 m were logged for several geophysical properties including magnetic susceptibility and spectral gamma radiation (SGR).

SGR is a particularly useful tool as it is non-destructive, fast, affordable, and applicable even in cased boreholes. Among the lake deposit of the Chalco sub-basin, 388 total tephra layers (≥1 mm in thickness) were reported from the core description. Tephra layers with specific gamma-ray signatures present a challenge for extracting the primary signals caused by climatic agents. We propose a protocol to identify tephra layers embedded in other sediments using high-resolution SGR.

After extracting the non-volcanic primary signal, we applied a suite of evolutive cyclostratigraphic methods to the Lake Chalco downhole logging data, with a focus on gamma-ray. The high-resolution gamma-ray results suggest that the Lake Chalco sediments contain several rhythmic cycles with a quasi-cyclic pattern comparable with Pleistocene climate evolution, allowing to calculate of a ~500-kyr time span for the Lake Chalco sediment deposition.

The new hydraulic coring system Hipercorig was developed to recover undisturbed long cores from deep lacustrine sediment archives that record past environmental conditions and changes (Harms et al., 2020). Here we report initial results from the deep lake drilling project ‘Hipercorig Hallstatt History’, which succeeded to recover two 41m and 51m long cores and to conduct downhole logging in spring 2021 with the Hipercorig System on Lake Hallstatt. This inner-alpine lake, characterized by very high clastic sedimentation rates, is located in the heart of the UNESCO World Heritage region Hallstatt - Dachstein – Salzkammergut, whose early history of Stone Age settlement and salt mining is still not yet fully understood. Also, there is a lack of reliable observational data on past environmental and climatic conditions, and frequencies and impacts of meteorological and geological extreme events of that time, that are needed to holistically understand past environmental-human-environmental interactions. The new >50 m long sediment cores from Lake Hallstatt now overcomes the previous coring-depth limit (16 m subsurface, dated to ~2.3 cal ka BP) and covers a presumably continuous sedimentary succession throughout the Holocene and Late Pleistocene since the retreat of the Traun glacier. Here we present first results from the Hipercorig coring and logging campaign, along with initial results from whole-round core analyses (Multi-Sensor-Core-Logging; and X-ray Computed Tomography) and preliminary Core-Log-Seismic-Integration, revealing unprecedented scientific samples and data, that will provide unique insights into the early development of one of the oldest cultural landscapes in the world.

A 6-meter drill core from Merensky Reef, Bushveld Complex, South Africa, was scanned in detail with a drill core scanner based on Laser Induced Breakdown Spectroscopy. The purpose of the investigation was to visualize variations in the chemical composition along the core, and following a mineral classification of the LIBS data, of variations in the mineral chemical composition as well.

The LIBS technology is based on atomic emission spectroscopy, in which the excitation of the atomic species occurs in-situ on the sample surface. The excitation source was a pulsed 50 mJ 1064 nm Nd:YAG laser, and the emitted light was collected with a high-resolution wide-range echelle spectrograph with CCD detector. For validation purposes, selected samples were analysed with bulk chemical analysis and electron probe microanalysis as well.

Distinct trends could indeed be extracted from the 6 m core section through the Merensky Reef. From a saw-cut core surface without further preparation, a continuous record could be extracted consisting of bulk chemical patterns, modal composition, and direct neighbourhood. The data can be used to highlight the presence of unusual patterns and to relate them to Ni, Cu, PGE or other mineralization. When applied to different core sections, it may become an important tool for comparing lateral variability of diagnostic horizons in vertical sequences in layered intrusions such as Merensky Reef and UG-2.

A key aim of the ICDP Oman Drilling Project is to constrain magmatic processes beneath fast-spreading mid-ocean ridges. Several drill cores from the Samail ophiolite (Oman), which is regarded as the best-preserved piece of ancient oceanic lithosphere on land, were obtained. Drill core GT1 covers about 400 m from the layered gabbro section between ~1200 and 800 m above the mantle transition zone (maM). The vast majority of the samples recovered are (olivine-) gabbros with a few cm-scale layers of anorthosite, troctolite, and wehrlite. We found a large scale fractionation trend from 800 to 1070 maM in the primary phases olivine, clinopyroxene, and plagioclase that can be subdivided into five smaller trends, each between 25 and 80 m thick. Above 1070 maM, phase compositions change to more primitive compositions over a 15 m thin horizon, revealing decameter-scale fractionation trends between 1090 and 1170 maM. Significant zoning in clinopyroxene, that was absent below, is observed above 1070 maM. These trends are confirmed by bulk rock chemical and mineral trace element data and indicate that fractional crystallization occurred within the layered gabbros. The fabric symmetry varies along the core with significant lineation at the primitive base and top of the core and almost pure foliation dominating the most evolved horizon at about 1070 maM. Variable fabric symmetries and the observed differences in clinopyroxene zoning could result from different liquid/solid ratios caused by on-going fractional crystallization and occasional magma replenishment.

Site C0023 in the Nankai Through subduction zone was established in 2016 to investigate the temperature limits of deep subsurface life. Here, we report on the detection of intact polar lipids and their degradation products in sediments recovered from this site where temperatures reach values close to the known limit of life of ca. 120°C at the bottom of the core at 1170 m. Lipid biomarkers characteristic for sedimentary methanogens and unclassified heterotrophic archaea were detected within the methanogenic zone where temperatures transition from mesophilic to thermophilic conditions. These include glycerol, butanetriol and pentanetriol dialkyl glycerol tetraethers (GDGT, BDGT, PDGT) and archaeol with glycosidic headgroups. In this zone, elevated intact polar lipid concentrations compared to vegetative cell numbers suggest substantial accumulation of fossil lipids over time at temperatures of ca. 45 to 50°C. A stark decline in both intact lipids and their degradation products below this depth coincides with the onset of the catagenic zone and the subsequent thermal breakdown of organic matter. The detected lipids are degraded at different reaction rates, reflecting their different thermal stabilities. We also observe a selective removal of GDGTs according to the number of rings in their core structure with important implications for the application of these compounds as paleoenvironmental proxies. This study suggests that intact polar lipids provide a time-integrated signal on microbial community distributions and provides insights into abiotic processes affecting their preservation.

Studying active hydrothermal systems in the deep-sea provides unique opportunities for furthering our understanding of how polymetallic seafloor massive sulfide accumulations form. The possibility of sampling the ore-forming fluids that are emitted through sulfide-sulfate chimneys is particularly powerful. The use of gas-tight samplers in collecting hydrothermal vent fluids facilitates measurements of the contents of dissolved gases and metals and allows for accurate reconstructions of in situ pH and redox conditions.

Metal transport in seafloor hydrothermal systems is affected by fluid-rock interactions, magma degassing, phase separation, and subseafloor mixing of the upwelling hydrothermal fluids with entrained seawater. The composition of basement hosting deep-sea hydrothermal vent systems, i.e. the type of rock involved in fluid-rock interactions, ranges from ultramafic to felsic. Geotectonic settings of vent systems vary from mid-ocean ridges to backarc spreading centers to island arc and intraplate volcanoes, which show strong contrasts in water depths and influx of magmatic fluids. Our recent compilation of vent fluid data (doi:10.1029/2020GC009385) allows a first complete assessment of how these differences affect the compositions of fluids in the root zones of hydrothermal systems. Beyond an examination of these general differences, valuable insights into processes in the discharge zone of hydrothermal systems can be obtained from detailed fluid sampling in individual vent fields. We present examples from selected arc/backarc hydrothermal vent sites in felsic crust for how vent fluid compositional data and thermodynamic computations can yield detailed insights into km-scale metal transport as well as smaller scale processes of zone refining.

The axial volcanic edifice of Maka at the North Eastern Lau Spreading Centre shows intense hydrothermal activity at two vent sites (Maka HF and Maka South) emitting fluids of distinct composition. We present trace element and isotope data for hydrothermal fluids and related sulphide precipitates that actively form on the seafloor at 1525 to 1543 m water depth. Hydrothermal activity at Maka HF is present as vigorously venting black smoker-type fluids reaching temperatures of ~330°C. High metal (e.g. Fe, Mn, Li) and REE contents in the vent fluids, are indicative for a rock-buffered hydrothermal system at low water/rock ratios. At Maka South venting of white smoke at up to 300°C occurs at several sites. Measured fluid pH (4.53-5.42) and Mg, SO₄ and Cl concentrations are depleted compared to seawater, whereas Li, Mn and H₂S are enriched, indicating a three-component mixing model between seawater, a boiling-induced low Cl vapor and a black smoker-type fluid at Maka South. Trace element systematics in hydrothermal pyrite also report on the contribution of these different fluid-types. Pyrite that precipitates from low Cl vapor-rich fluids at Maka South is characterized by high As/Co (>10) and Sb/Pb (>0.1) values that we relate to a boiling-induced element fractionation between the vapor (As, Sb) and liquid phase (Co, Pb). The Se/Ge ratio in pyrite may be used as a new tracer for fluid-seawater mixing. Sulfur and Pb isotopes in hydrothermal sulphides indicate a common metal(loid) source at the two vent sites by host rock leaching in the reaction zone.

Submarine “black smoker” systems and their associated seafloor massive sulfides (SMS) may represent economic resources for future generations. However, the processes leading to spatial variations in the mineralogical and chemical composition of subduction zone-related hydrothermal systems remain poorly constrained. The large submarine caldera of Niuatahi volcano hosts several active hydrothermal vent sites associated with faults at the caldera wall and with young post-caldera volcanic cones, venting vapor-rich and black smoker-type-fluids with temperatures up to 334 °C. We combine bulk sulfide chemistry with in-situ trace element data and S- and Pb isotopes of pyrite, sphalerite, chalcopyrite to decipher key ore-forming processes causing spatial variations in metal(loid) enrichment.

We refer these spatial variations within the caldera to a continuum between magmatic fluid-dominated venting at the central cones (high Cu, As, Bi, Te, Au, Sb, δ³⁴S = -10.6 - 2.7 ‰) compared to fluid-rock interaction and seawater mixing at the caldera wall (high Au, Ag, Cd, Pb, δ³⁴S = -0.6 - 6.3 ‰). Lead isotopes of sulfide separates suggest a connected hydrothermal circulation cell and/or similar source rock compositions in the central part of the caldera compared to a discrete one at the caldera wall. We conclude that metal(loid)s from distinct sources (magmatic volatiles vs. host rock leaching) combined with hydrothermal fractionation (e.g., boiling) leads to spatial variations in economically relevant elements (e.g., Te, Au, Ag, Bi, Se, Co) in submarine caldera-hosted hydrothermal systems. This has important implications on exploration of fossil SMS or volcanogenic massive sulfide deposits on land.

The shallow submarine Kolumbo volcano , located in the 5 Ma-to-present Aegean volcanic arc in Greece, hosts an active hydrothermal system currently forming polymetallic seafloor massive sulfide (SMS) mineralization on the seafloor, with high As, Ag, Au, Hg, Sb and Tl contents. It is one of the few known SMS deposits associated with continental margin volcanism. The hydrothermal system of the Kolumbo volcano represents an active hybrid analogue style of epithermal and VMS mineralization. The particular geological setting of the Kolumbo volcano in the Anydros basin makes it a great natural laboratory to investigate the metal flux as the underlying units outcrop on the neighboring islands of Santorini, Ios and Anafi . To this day, it is not clear to which extend the metals in the fluid derive from a magmatic source or if they are leached from the basement rocks by magmatic-hydrothermal fluids. Whole rock geochemistry of the basement and sedimentary rocks allows identifying the potential metal reservoirs in the system. The basement rocks can add metals to the system either by leaching through magmatic-hydrothermal fluids or contamination of the melt by assimilation. Sulfur and Pb isotope analysis allow to track contribution of the basement rocks to the metals/ligands budget of the fluids by comparison with the sulfates and sulfides of the Kolombo SMS. Constraining the metal reservoirs involved in marine magmatic-hydrothermal systems is crucial to understand the formation of SMS and variability in the metal endowment between the deposits .

Target settings to secure sustainable access to raw materials include seafloor massive sulphide (SMS) resources. Gold-rich SMS deposits, are often the result of complex interplay of multiple Au enrichment events. Recent studies have shown that high-grade Au ores result from Au remobilization from preexisting mineralization, driven by fluid-induced coupled dissolution-reprecipitation (CDR) reactions; however investigations into this process in modern Au-rich SMS, are lacking. To tackle this issue, Au-rich [Au_BULK≤32ppm; Au/(Cu+Zn+Pb)=1.9], polymetallic (Sb, Tl, Hg, Ag, Mo, Te) diffuser chimney samples from the active Kolumbo shallow-water SMS system, Hellenic Volcanic Arc, were geochemically and texturally examined using combined SEM-EDS imaging, and LA-ICP-MS spot analysis and trace element mapping. Recrystallized subhedral auriferous arsenian pyrite2 (≤65 ppm Au, ≤13290 ppm As) records textures, being porosity growth concurrent with the presence of native gold and accessory pore-filling Pb-Sb sulfosalts, indicating that recrystallization proceeded via fluid-mediated CDR reactions. The latter caused replacement of earlier, colloform-banded, Au-rich arsenian pyrite1 (≤130 ppm Au, ≤9057 ppm As) by pyrite2, and liberated invisible Au (nanoparticles and/or lattice-bound) and associated elements (Pb, Sb). Furthermore, textural evidence indicates that porous orpiment with Pb-Sb sulfosalt inclusions, showing extreme Au enrichment (≤861 ppm Au) compared to other SMS deposits worldwide, was formed by replacement of Au- and As-rich Pb-Sb sulfosalts (≤132 ppm Au, ≤6550 ppm As) via CDR reactions. This study provides significant evidence that in arc-related Au-rich polymetallic SMS deposits, native and invisible Au are closely associated to various sulfides/sulfosalts, and CDR reactions may contribute to upgrading Au grades during hydrothermal reworking.

The site selection procedure for a high-level radioactive waste repository in Germany is based on the Repository Site Selection Act (StandAG, 2017) and comprises three phases. Commissioned by the Bundesgesellschaft für Endlagerung mbH (BGE), the BGR contributes to this procedure with the projects „GeoMePS“ and „ZuBeMErk“, which aim to develop recommendations for phase 2 of the site selection procedure – the surface exploration of siting regions. For this purpose, the BGR has developed a systematic approach that includes (1) deducing exploration targets, (2) compilation of geoscientific and geophysical exploration methods in a database structure, and (3) evaluation of case studies of national and international exploration programs. The deduction of exploration targets was based on the criteria and requirements as defined by the StandAG. Subsequently, the identified exploration targets together with a large number of geoscientific (e.g., geological mapping) and geophysical exploration methods (e.g., reflection seismics) were integrated and linked within the database – the so-called “GeM-DB”. All methods were evaluated according to their suitability and applicability for (a) the three defined host rocks (crystalline rock, claystone, rock salt) and (b) the previously defined exploration targets. In step (3) the BGR evaluates national and international exploration programs, for example the site selection processes for deep geological repositories in Switzerland or Sweden, to infer additional exploration directives.The entire systematic approach aims to develop recommendations for a non-destructive and minimal invasive surface exploration program of siting regions in Germany, regarding the lithological, structural, mechanical, and hydrogeological characterization of the different host rock formations.

Seit 2013 hat in Deutschland die Standortsuche für ein Endlager für hochradioaktive Abfälle mit dem ersten Standortauswahlgesetzes (StandAG) neu begonnen. Viele Jahrzehnte lang wurde in Deutschland die Entwicklung von Endlagerkonzepten und Sicherheitsanalysen für ein Endlager in einem Salzstock priorisiert, während Endlagerkonzepte für Ton- und Kristallingestein erst seit zwei Jahrzehnten berücksichtigt werden. Zielstellung eines vergleichenden Standortauswahlverfahrens ist, bis 2031 einen Standort zu finden, der für 1 Million Jahre die bestmögliche Sicherheit für den Einschluss hochradioaktiver Abfälle bietet.

Sicherheitstechnischer Grundgedanke ist dabei der Einschluss der Schadstoffe im sogenannten einschlusswirksamen Gebirgsbereich (ewG). Im Mittelpunkt eines Langzeitsicherheitsnachweises steht folgerichtig der systematische Nachweis des langfristig sicheren Einschlusses der endgelagerten Abfälle durch den Nachweis der Integrität des einschlusswirksamen Gebirgsbereichs, als wesentliche geologische Barriere, sowie der geotechnischen Barrieren.

Aufgrund ihrer einzigartigen Eigenschaften, u.a. Dichtheit und Kriecheigenschaften, werden Salzgesteine in Deutschland und weltweit seit Jahrzehnten bergbaulich und insbesondere für die Energiespeicherung genutzt.

Während Steinsalz in Salzstöcken (Typ: steile Lagerung) vor allem in Nordwestdeutschland verbreitet ist, dominieren in Mitteldeutschland flach gelagerte Salzgesteine (Typ: flache Lagerung) sowie in Teilen Nordostdeutschlands Salzkissen (Typ: Salzkissen). Beide Typen der „flachen Lagerung“ (bedded salt) spiegeln in ihrer lateralen Erstreckung – abgesehen von diagenetisch bedingten Veränderungen – weitgehend sedimentationsbedingte Lagerungsverhältnisse wider.

Ausgehend von der Darstellung der wirtsgesteinsspezifischen Randbedingungen der verschiedenen Salzgesteine fokussiert dieser Beitrag auf die Vorgehensweisen für den Integritätsnachweis des geologischen Barrieregesteins Salz auf Basis vorliegender Erfahrungen und entsprechender Referenzstudien sowie Analogbeispielen. Im Ergebnis wird nachgewiesen, dass Endlagerkonzepte in der flachen Lagerung in der Konstellation Salzkissen aufgrund eines standortspezifischen Multibarrierensystems erhebliche sicherheitstechnische Vorteile bieten.

Claystones in the deep subsurface have various barrier-effective properties for solute transport. Changes in the mineralogical composition (incl. fluids), the structure of claystones in the strict sense, as well for claystone formations in a broader sense, and their regionally different geological development cause a great variety of petrophysical, mineralogical and geochemical properties of claystone sequences. Therefore, sound knowledge of the characteristics of claystone formations is required for the different usage options of the subsurface in order to provide technical support for economic, political and scientific investigations or decisions and to ensure the safety of underground geosystems.

In our study MECHTON existing data will be used and evaluated for petrophysical and further regional characterisation of the lithological expression of claystone formations. For this purpose, statistical methods are used for the interpretation of geophysical borehole measurements in order to record changes in the regional lithological characteristics and the spatial-petrophysical characteristics of a potentially repository-relevant claystone formation, the Opalinus Clay.

The objectives of the study will be presented and methods for characterising the lithological and petrophysical properties of claystone on basis of logs will be discussed. The focus is: How can regionally characteristic properties of claystone be recorded from logs and transferred to a larger study area?

The rock mass around man-made underground structures inevitably experiences major changes in hydraulic and mechanical properties, commonly referred to as excavation damage. In host rock formations for underground nuclear waste storage, such an excavation damaged zone (EDZ) is potentially critical and therefore requires reliable field data sets for safety assessment and the estimation of the long-term behavior. In this study, different on-site measurements were carried out in the EZ-B niche of the Mont Terri Rock Laboratory in order to characterize the EDZ with regard to its changed hydraulic effectiveness and its mechanical and geophysical properties.

The discrete fracture network (DFN) around the EZ-B niche was investigated using a transient airflow permeameter as well as combined microscopic imaging with automatic evaluation. The DFN exposed in the non-lined tunnel with measured hydraulic fracture apertures of 84 ± 23 μm basically represents a network for advective fluid transport. Due to their formation mechanism, we encountered noticeable differences between the newly-formed unloading fractures and the reactivated tectonic discontinuities. Geomechanical and geophysical characterization of the Opalinus Clay was conducted based on needle penetrometer testing at the rock surface. This proved to be a valuable tool for accurately determining the anisotropic uniaxial compressive strength of the claystone, but also led to a general underestimation of other physico-mechanical parameters in bedding-parallel direction, presumably due to unperceived microcracks.

For decades, claystone is investigated as a likely host rock material for the deep geological disposal of highly radioactive waste. To ensure safe operation, knowledge about the long-term (thermo-hydro-) mechanical behavior of clay rock is of significant relevance: How will the excavation induced differential stresses gradually dissipate while causing convergence?

Laboratory triaxial tests on the mechanical behavior allow for the controlling of major and minor principal stress (differential stress), pore pressure (effective stress), saturation, temperature and loading history. Long-term deformation tests running at low differential stresses reveal gradually declining deformation rates (consolidation + primary creep). With time, the deformation process asymptotically approaches an apparently constant deformation rate at constant volume (secondary creep). At higher differential stresses, accelerated tertiary creep occurs, associated with dilatant deformation and forming of new microcracks, leading to final failure of the specimen. In claystones the primary consolidation process is slow and comparatively well understood: due to low hydraulic conductivity pore fluid is slowly squeezed out, at the same time rearrangement of clay particles and micro grains takes place leading to changes in the microstructure. Moreover, rearrangements in the grain skeleton with a variable deformation rate can occur at constant effective pressure. This creep process is hard to determine and still poorly understood. Only very long creep tests give the possibility to detect secondary creep and to distinguish it from primary consolidation processes.

Creep tests run over several months/years on clays from Mont Terri give examples of the settlement mentioned and different types of creep.

In Claystones, the storage concept for spent nuclear fuel mainly consisting of uranium is based among others on the isolation of the radionuclides within the effective containment zone due to the high retention capacity of the host rock. The transport properties are typically determined in laboratory experiments representing the host rock and for defined geochemical conditions. However, previous numerical studies have shown for the Swiss Opalinus Clay, that sorption of uranium and with that the migration are highly affected by variations in the composition of the porewater resulting from mineralogical heterogeneities. The hydro-geological system of the Opalinus Clay is characterized by a 210 m thick, low permeable section embedded between aquifers. The porewater components of the low permeable section show an asymmetric geochemical gradient towards the aquifers due to diffusive exchange over several million years between them. By modelling the past history of the porewater based on multi-component diffusion simulations, we quantify uranium migration for one million years considering the changing geochemical conditions as a result of the hydro-geological system. Our results show, that uranium is retained within the theoretical effective containment zone and adjacent aquifers are not reached. Consequently, a clay rock with a thickness > 100 m in a geochemical and mineralogical framework like the Opalinus Clay would be a suitable host rock for the storage of uranium from spent fuel.

Pure and pristine Archaean and Palaeoproterozoic banded iron formations (BIFs) are excellent marine geochemical archives, especially of original rare earths and yttrium (REY) characteristics. As recently demonstrated for the Mt.Ruker BIF in Antarctica^[1], ultrapure BIFs preserve seawater-like REY distribution with heavy REY_SN enrichment and light REY_SN depletion (SN: shale-normalized). Our results indicate that a prominent feature of the REY signature of seawater throughout Earth’s history has been a super-chondritic Y/Ho ratio which falls between that of potential detritus and the maximum Y/Ho ratio of modern seawater. Another more subtle and fragile proxy of modern seawater is the W-type lanthanide tetrad effect (LTE) which results from the slightly differing bonding characteristics of individual REY in chemical complexes, due to the specific electron configuration of the REY³⁺ ions. This W-type LTE is found in pure marine carbonate rocks and in BIFs, and confirms the primary and marine origin of their REY distribution. The preservation of uniform, super-chondritic Y/Ho ratios in combination with the W-type LTE in chert and Fe-oxide BIF bands is an excellent tool to test the pristineness of geochemical signals in such samples as well as evidence for the primary origin of banding in BIFs.

[1] Ernst D. M. and Bau M. (2021) Banded iron formation from Antarctica: The 2.5 Ga old Mt. Ruker BIF and the antiquity of lanthanide tetrad effect and super-chondritic Y/Ho ratio in seawater. Gondwana Research 91, 97–111.

Rare earth elements (REEs) have become a key component in many technological applications. Due to the rapid increase in their use, the potential environmental exposure has also expanded. However, the effects on the ecosystem have not been yet thoroughly evaluated, leaving many knowledge gaps. To evaluate the effects of REEs, a set of experiments with acute and chronic exposure were performed on photosynthetic organisms.

The effects of acute exposure of four elements (cerium, gadolinium, lanthanum and neodymium) in two set upsexperimental scenarios with different pH values (6 and 4), was evaluated on three testing species: Raphidocelis subcapitata, Lepidium sativum and Vicia faba. In the rResults obtained in the acute exposure, a higher toxicity at pH 4 was observedindicated higher toxicity levels, which could be explained by a higher bioavailability of the elements. From the relative calculated median effective concentrations (EC50s), R. subcapitata was the most sensitive species, followed by L. sativum and lastly, V. faba.

Further investigations focused on , the chronic exposure of lanthanum and cerium was evaluated on Raphidocelis subcapitata. After a 28 days exposure, results showed a growth inhibition effects effect and increasing a bioaccumulation (from day 7 to 28) with effect at the end of the test. Moreover, endpoints regardedfluctuating values of the relative as biomarkers of stress (ROS, CAT, and SOD)., fluctuated during the sampling days during the exposure (day 7, 14, 21 and 28).

Rising rare earth elements (comprising the 15 lanthanoids plus yttrium (REY)) processing and use can lead to increased anthropogenic REY release into the environment, representing a potential environmental concern. Seaweeds due to their key ecological role as primary producers, habitat forming organisms and their tendency to accumulate metals have been largely used for monitoring anthropogenic pollution in coastal areas. In this study we assessed REY contents in Saccarina latissima seaweed to identify potential anthropogenic REY sources, and to relate accumulation patterns to different local abiotic and biotic conditions, including light regime, salinity, temperature and nutrient concentrations which can change over space and time. S. latissima specimens were collected at 2 depths (1-2 m and 8-9 m) in 4 locations at 4 time points (from May to August) along the Norwegian coastline over a germinating season. REY concentrations were analysed in freeze dried samples, each constituted by a pool of 10 specimens, with ICP-MS and relations between seaweed and REY accumulation, growth and protein contents were evaluated. Results provided in this study are expected to deepen the knowledge of the environmental bioavailability and accumulation patterns of REY along a spatial and temporal environmental gradient.

Rare earth elements, comprising the 15 lanthanoids (LN; IIIb in the Periodic Table) plus yttrium are critical elements for a wide range of applications, including new and traditional industries as renewable energy, automotive industries, metallurgy as well as agriculture and medical diagnostics. Rising REY production and use can lead to an increased release into the environment and represents a potential environmental concern. However, the bioavailability and effects of REY and anthropogenic REY-chemical complexes (ACC-REY) remain significantly understudied in aquatic organisms.Here, we evaluated the impact of different REY and ACC-REY on early life stages of two fish species: zebrafish (Danio rerio) as freshwater model species and cod (Gadus morhua) as marine species. Fish embryos were exposed to nominally 2000, 200, 20, 2 and 0.2 µg L^-1 of different REY compounds. Mortality, hatching, larvae development and morphometry were monitored. At the end of the exposure, a subsample of larvae from each treatment was subjected to image analyses to evaluate larvae mobility and behaviour. These individuals were thereafter analysed immunohistochemically to investigate REY impacts on neural activity. First results showed increased mortality and larvae deformation at higher REY concentrations. Further, transcriptomic responses are analysed to reveal underlying molecular effect mechanisms and affected pathways. Results from this study will provide knowledge on the eco-toxicological risks associated to increasing REY release into aquatic ecosystems.

There is a potential risk that geochemical cycles of critical metals (e.g Be and W) will be affected in the pristine environment, when mining of these metals increases to meet the demand in green technology. To understand their geochemical behavior and environmental impact are of high importance to ensure a sustainable development of mine waste and water management. Beryllium and W are identified as elements of potential concern that can have adverse impact on humans and ecosystems. The release of Be and W from two historical skarn tailings (Smaltjärnen and Morkulltjärnen repositories) from the same ore body (Yxsjöberg/Sweden), and the impact on epilithic water diatoms in downstream neutral surface water were studied. Dissolved Be had been released in high concentrations from danalite (Be₃(Fe_4.4Mn_0.95Zn_0.4)(SiO₄)_3.2S_1.4) due to oxidation and acidifications in tailings stored open to the atmosphere (Smaltjärnen). Tungsten was released in low concentrations as an indirect consequence of sulfide oxidation. Thus, CO₃^2- released from calcite buffering the acid produced had exchange with WO₄^2- on scheelite (CaWO₄) surfaces. High concentrations of dissolved W were present downstream the covered and water saturated tailings (Morkulltjärnen). Beryllium and W are considered as immobile elements, but both were transported in neutral mine drainage (NMD) >5 km downstream the mine site. The water quality from both repositories had negative impact on epilithic water diatoms >2 km from the site. This study shows the importance to understand the geochemistry and mineralogy before choosing remediation method for mine tailings enriched in critical metals, and the need to study NMD.

Scandium (Sc) is often included in the group of rare earths and yttrium (REY), but in contrast to the REY, knowledge on its behaviour in the hydrosphere is rather limited. However, a better understanding of the distribution and behaviour of Sc is important, as its use in industry is expected to grow exponentially in future, which will likely result in an increasing Sc release into the environment.

Here, we report and discuss Sc and REY data for the “dissolved fraction” (<0.2 µm) from twelve pristine rivers in Sweden sampled in May 2019. All rivers are characterised by low conductivity (18-60 µS/cm²), slightly acidic to neutral pH (6.04-7.11) and elevated dissolved organic carbon (DOC) concentrations (5.50-10.3 mg/L). Their shale-normalised REY patterns show a slight enrichment of heavy REY (HREY) compared to light REY (LREY), and negative Ce and positive Y anomalies. Some rivers also show a negative Eu anomaly. The REY distribution in these rivers is controlled by nanoparticles and colloids (NPCs) present in the dissolved fraction. Compared to data from 2014, all rivers show higher REY concentrations and a slightly lower HREY enrichment, suggesting a higher NPCs content in the rivers in 2019. Scandium concentrations vary between 0.363nM and 1.17nM and increase with increasing DOC and Fe concentrations. This suggests that Sc has a strong affinity for NPCs, similar to the REY. The association of Sc with DOC further suggests a significant impact of organic ligands on the behaviour of Sc in the hydrosphere.

Mantle convection is a fundamental driving force for the tectonic activity of our planet. It is commonly perceived that mantle convection is difficult to constrain directly. Its processes, however, affect the surface of the Earth and leave an imprint in the geological record. One response to topographic changes driven by mantle convection is the development of unconformities in the geological record (i.e. the absence of a stratigraphic layer), due to non-deposition or erosion. Modern geological maps allow systematic mapping of such unconformable surfaces at the continental scale.

Here we report our recently published work on the extraction of conformable and unconformable contacts (continent-scale hiatus mapping) in geological series across America, Europe, Africa, and Australia, from the Upper Jurassic onward. We find significant differences in the spatial extend of hiatus patterns across and between continents at geological series, ten to a few tens of Million years (Myrs). This is smaller than the mantle transit time, which, as the timescale of convection, is about 100–200 Myrs, implying that different timescales for convection and topography in convective support must be an integral component of time-dependent geodynamic Earth models. For the Cenozoic sedimentary cover of Europe the maps show a large hiatal surface of the Paleocene. This surface precedes the arrival of the Iceland plume and the change in motion of the North Atlantic ridge in the early Eocene.

Our results call for intensified collaboration between geodynamicists and geologists to improve our understanding of interregional-scale geologic events.

The Cenozoic tectonic evolution of Northern Europe involves a number of events that are difficult to reconcile with an intra-plate setting, including magmatic events and topographic changes that are located far from plate boundaries. It is entirely plausible to relate these events to sublithospheric processes in a vigorously convecting mantle. However, traditional mantle convection models are difficult to link to the spatiotemporal constraints provided by geologic archives, because their output invariably depends on the assumptions of poorly known and arbitrary initial conditions. Here we explore a new class of time-dependent global geodynamic Earth models, known as retrodictions, which are based on inverse approach to
reconstruct past mantle flow and structure. Our high resolution, compressible, global mantle flow retrodictions involve more than 670 million finite elements.
Going back 50 million years ago they reveal a preferential flow direction in the sub-European mantle related to material influx from the North Atlantic realm. The retrodictions allow us to track material back in time from any given sampling location, making them potentially useful, for example, to geochemical studies. Our results call for improved estimates on non-isostatic vertical motion of the Earth’s surface – provided, for instance, by basin analysis, seismic stratigraphy, landform studies, thermochronological data, or the sedimentation record – to constrain the recent mantle flow history beneath northern Europe and suggest that mantle flow retrodictions may yield powerful synergies across different Earth sciences disciplines.

The evaporitic Haselgebirge Formation hosts in many places small occurrences of basaltic rocks. The geochemistry of these basalts can potentially provide information about the tectonic setting of the Haselgebirge Formation and the evolution of the Meliata ocean, respectively. XRD analysis and thin sections give hints to the original geochemistry, however the basalts altered significantly in contact with brines. Therefore, we present here 70 new XRF analyses of these basaltic rocks from various localities (Pfennigwiese, Annaberg, Wienern, Hallstatt, Moosegg, Lammertal) and compare the results with previous data from local studies (Gruber et al., 1991; Kirchner 1979; Kirchner 1980a; Kirchner 1980b; Kralik et al, 1984; Leitner et al., 2017; Schorn et al., 2013; Ziegler, 2014; Zirkl, 1957). Based on the concentrations of immobile trace elements (Zr, Nb, Y, Ti), a predominance of MORB-like compositions is observed for the Lower Austrian occurrences and for the locality Wienern (Grundlsee). On contrast, basalts from the localities Lammertal, Moosegg and Hallstatt have predominantly within-plate-type compositions. Both groups plot for the most part in the plume source field after Condie (2003). We discuss a striking regional (east-west) difference of basalt types in terms of existing palinspastic models for the Haselgebirge formation (Leitner et al., 2017; Stampfli & Borel, 2002; McCann et al., 2006).

The Werra-Fulda mining district located in Central Germany hosts a world-class deposit of sulfate bearing potash salts. The Permian (Zechstein, ca. 255 Ma) evaporite sequence was intruded by mafic melts in the Neogene resulting in magmatic dykes as well as sill structures frequently observed in the subsurface mining galleries. Furthermore, volcanic rocks intersect the overlaying strata (mainly Buntsandstein and Muschelkalk) at localized spots forming distinct mountains.

In this study, samples from subsurface mafic dykes and surface volcanic rocks were intensively documented, sampled, and analyzed for their major, minor, and trace element composition. The geochemical analyses allow the characterization of the rocks that show compositions typical for within plate basanites and nephelinites with minor occurrences of phonolitic dykes. Results of the study also indicate the interaction of magma with adjacent potash salts and partly alteration of potassium and sodium concentration.

Two distinct trends in magmatic composition are revealed suggesting at least two sources for the magmatic feeder system in the local area. The geochemical results are compared to published data of the area and nearby volcanic complexes in the Rhön, Vogelsberg, Westerwald, and Siebengebirge. Additionally, we tested the fission-track and (U-Th-Sm)/He dating technique by using apatite from more than 100 magmatic rock samples. Preliminary, results provide two magmatic events: one at about 21 Ma and the other at about 13 Ma. Both events are accompanied by localized tectonic reactivation.

In Germany, the first apatite fission-track study was performed in the Odenwald (Wagner 1968) with the results of Mesozoic apatite fission-track ages. The presentation will re-examine the Mesozoic-Cenozoic exhumation history of the Odenwald and Heidelberg area with new thermochronological data. The Odenwald as part of the Mid-German Crystalline Zone is characterized by outcrops of the Variscan basement and overlain Mesozoic and Cenozoic strata. Towards the West, the Variscan Basement is bound by the Upper Rhine Graben basin and towards the East by the Mesozoic and Cenozoic cover. Variscan basement rocks, Mesozoic, and Oligocene sandstones have been studied by apatite fission-track and apatite (U-Th-Sm)/He thermochronology.

Apatite fission-track ages range between 70.4±3.8 Ma and 116.7±5.2 Ma and apatite (U-Th-Sm)/He ages between 66.4 ± 4.0 Ma and 121.3 ± 16.7 Ma. Apatite of the Oligocene sandstone deposit near Heppenheim revealed a central fission-track age of 49.4±3.6 Ma. The thermochronological data show a differentiated age distribution with cooling ages getting younger from north to south. Consequently, we assume that exhumation of the rocks in the northern part set in earlier a took place slower than in the southern part of the Odenwald. Numerical modelling using the software code HeFtyimplies either a high Cretaceous heat flow or a maximum of up to 2830 meters of Mesozoic sedimentary rocks that could have covered the Odenwald crystalline basement during the Cretaceous. The modelled t-T-evolution hints at two major phases of exhumation, one in the Cretaceous and one in the Neogene.

Proglacial areas are extremely unstable and characterized by highly intensive geomorphic processes. In this study, we consider a typical proglacial area on the Caucuses – Djankuat river catchment. This research presents the first results for the complex monitoring of exogenic geomorphic process rates within the selected catchment. A repeated UAV survey for selected sites conducted in September 2019 and in August 2020 was the primary method. Also, high-resolution DEMs derived from stereo satellite images and the existing data obtained in field observations were used. It was determined that about 4122 ± 179 t yr^-1 enters the glacier’s surface from the located above rockwalls due to rockfalls and avalanches, which corresponds to the erosion rate – 1.29 mm yr^-1. The surface level averagely decreased by 0.48 m between surveys in the river valley just downstream from the glacier. The maximum losses were determined for the glacier front and buried ice outcrops, where values were -1.59 m (buried ice on the left valley side), -2.72 m (buried ice on the right valley side), -3.17 m (glacier front). The highest geomorphic intensity in the proglacial areas apparently associated with the rapid buried ice melting and occurs with a slight delay after the glacier retreat. Specific attention in proglacial areas should be paid to the quantitative assessment of extreme event consequences, which lead to main terrain transformations, sediment yield peak values, and, eventually, to total erosion.

The study was supported by the Russian Science Foundation (project No. 19-17-00181).

The fjord-type Lake Melville is located in Labrador, Eastern Canada, as part of the Hamilton Inlet System. It is mainly characterised by riverine freshwater influx into its western end and intrusion of saline water from the Labrador Sea through the shallow Rigolet Narrows.
Previous studies assumed that the retreating Laurentide Ice Sheet (LIS) caused the deposition of a typical glacial sediment sequence when its margin reached Lake Melville between 10,000 to 8,000 years ago (King, 1985; Syvitski and Lee, 1997). However, as suggested for other sites (e.g. Great Slave Lake; Christoffersen et al., 2008), the up to 400 m thick sediment package might contain pre-deglacial sediment because Lake Melville potentially persisted as a subglacial lake underneath the LIS.
Initial measurements and lithological investigations on two selected sediment cores (~14 m and 16 m) recovered during expedition MSM84 (2019) indicate a significant change in lithology and selected sediment-physical parameters within the lowermost two meters. First 14C-dates of gastropod and bivalve remains resulted in a preliminary age model with an extrapolated basal age of ~11.6 ka cal BP, but hence pre-dating the local deglaciation. In accordance with sediment echosounder data, microscopic investigations and first XRF analysis, we assume that these initial findings point at sediment deposition in a subglacial lake environment. In a next step, we aim at significantly improving the age model by considering more 14C-samples from various sediment cores as well as conducting further multi-proxy analyses to test our hypothesis.

The Eocene-Oligocene transition (EOT, ~34Ma) marks a dramatic climate change and carbon cycle perturbation in the Cenozoic. Understanding the variations in export productivity associated with EOT provides important information about the feedback in regulating climate.
We use the new generated benthic and planktonic oxygen and carbon isotope records combined with paleoproductivity proxies - Biological Barium [bio-Ba MAR] and benthic foraminifera accumulation rates [BFAR] - to infer variations in productivity during the EOT period in relation to changes in climate and paleoceanography.
In addition, we present preliminary diatom diversity data. Marine diatoms have been known to be great contributors to the biological ocean carbon pump, so these data provide support for the understanding of these climatic events.
Samples are from the Atlantic (ODP 689 and 1090) and Indian (ODP 748) sectors of the Southern Ocean. Our multiproxy records show evidence of increased export productivity in different periods throughout the Southern Ocean across EOT. The increase in productivity revealed in the late Eocene (~37 Ma) corroborates with an increase in marine diatoms diversity, suggesting that it could have contributed to the decrease in atmospheric CO2 and consequently to the cooling state.
The timing of some observed changes differs in the sites of the Atlantic sector of the Southern Ocean. The increase in productivity in the early Oligocene in the farther to the south ODP 689 site may be related to the water mass changes and development of the Atlantic Circumpolar Current.

Benthic foraminifera inhabit diverse marine environments, including areas of persistent bottom currents and contourite drift deposition. Certain highly adapted epibenthic foraminifera colonize contourite deposits as opportunistic suspension feeders. A correlation between these assemblages and high bottom current velocities has been highlighted in previous studies from the Iberian Margin (e.g. Schönfeld, 2002), suggesting their applicability as reliable proxy for reconstructing bottom currents.

Our ongoing project aims to document biogeographic patterns of benthic foraminifera from extended contourite drift systems in the Atlantic Ocean. The results will provide a framework to evaluate the applicability of foraminifera-based proxy methods for reconstructing bottom currents in different Atlantic contourite deposits. Existing data from the mid-latitude Iberian Margin are complemented by new faunal data from surface samples at high (50-62°N; Björn and Gardar Drifts, Iceland Basin; Eirik Drift, southern Greenland Margin) and low latitudes (10°-22°S Campos Drift, Brazilian Margin).

Preliminary results show variations in faunal composition along gradients of current intensity. Low current velocities at Björn and Gardar Drifts (max. 10 cm/s) favor tubular agglutinated taxa such as Rhabdammina abyssorum and Saccorhiza ramosa. An association of hyaline attached species including Cibicides refulgens and Cibicidoides wuellerstorfi preferentially settle in intermediate flow speeds at the Eirik Drift (12-22 cm/s). Communities of Campos Drift dwell at higher current velocities (up to 80 m/s) and show increased abundances of Cibicides lobatulus, Globocassidulina subglobosa, and Planulina ariminensis.

Reference:

Schönfeld, J., 2002. Recent benthic foraminiferal assemblages in deep high-energy environments from the Gulf of Cadiz (Spain). Mar. Micropaleontol. 44, 141–162. https://doi.org/10.1016/S0377-8398(01)00039-1

Bottom current-induced sediments such as contourites contain fundamental information for reconstructions of water mass properties and ocean circulation. The distinction between contourites and other deposits on continental slopes is particularly complex in areas where downslope and along-slope sedimentary processes co-occur. Clear and easily applicable diagnostic criteria for properly distinguishing between contourites and other coarse-grained and/or graded deep-water deposits such as turbidites are still limited (e.g., de Castro et al., 2020) and mainly focus on sedimentological data. The present study investigates Pleistocene contouritic (~0.5 Ma) and turbiditic (~0.9 Ma, ~1.1 Ma) sequences from the SW Iberian Margin in the Gulf of Cádiz (IODP Site U1389), where thick contourite drift bodies with extensively intercalated turbidites are preserved (Stow et al., 2013). The aim of the study is to define diagnostic criteria based on benthic foraminiferal assemblage composition in order to differentiate between normally graded contourites and turbidites as well as reworked turbidites. The revealed “foraminiferal fingerprint” will allow for improving paleoceanographic interpretations of sedimentary archives from complex depositional environments along continental margins.

References:

De Castro, S., Hernández-Molina, F.J., de Weger, W., Jiménez-Espejo, F.J., Rodríguez-Tovar, F.J., Mena, A., Llave, E., Sierro, F.J., 2020. Contourite characterization and its discrimination from other deep‐water deposits in the Gulf of Cadiz contourite depositional system. Sedimentology.

Stow, D.A.V., Hernández-Molina, F.J., Llave, E., Bruno, M., García, M., Díaz del Rio, V., Somoza, L., Brackenridge, R.E., 2013. The Cadiz Contourite Channel: Sandy contourites, bedforms and dynamic current interaction. Mar. Geol. 343, 99–114.

The solid Earth aspects of relative sea-level change can dominate in low-lying coastal areas with potentially vulnerable to accelerating rates of sea-level rise. Global Positioning System (GPS) as companion tools to tide gauges allow long-term assessment of solid Earth deformation, thus essential for disclosing climate-forced mechanisms contributing to sea-level rise (SLR). So far, it has not been possible to measure shallow displacements that occur above the base of GPS monument because conventional positioning determines the vertical component of position changes resulting from displacements occurring beneath the foundation. We use an emerging technique, GPS interferometric reflectometry (GPS-IR), to estimate the rate of this process in two coastal regions with thick Holocene deposits, the Mississippi Delta and the eastern margin of the North Sea. We show that the rate of land motion from shallow compaction is comparable to or larger than the rate of SLR. Since many of the world's great coastal cities are built on river deltas with comparable Holocene sections, our results suggest that estimates of flood risk and land loss have been underestimated. We demonstrate environmental impact of parking lots and streets surrounding a monitoring site on GPS measurements. Such kinematic environments will perturb the amplitude of reflected signals to GPS sensors and thus leave time-variable imprints on GPS observations. Thus, obtaining desirable reflections for shallow subsidence monitoring could be challenging.

Natural methane gas release from the seafloor is a widespread phenomenon that occurs at cold seeps along most continental margins. Since their discovery in the early 1980s, seeps have been the focus of intensive research, partly aimed at refining the global carbon budget. However, deep-sea research is challenging and expensive and, to date, few programs have successfully monitored the variability of methane gas release over several weeks or more. Long-term monitoring is necessary to study the mechanisms that control seabed gas release. Located at 800 m depth on the Cascadia accretionary prism offshore Oregon, Southern Hydrate Ridge is one of the most studied seep sites where persistent, but variable gas release has been observed for more than 20 years. Using a series of instruments connected to the Ocean Observatories Initiative's (OOI) Regional Cabled Array observatory, we monitored the venting activity at Southern Hydrate Ridge over several months. We will present results from the systematic monitoring, which include in particular acoustic sensing of bubble plumes and time-lapse photography of selected vents at the seafloor. The data reveal a very dynamic system characterized by frequent and significant changes in seabed morphology and highly variable gas emissions. Acoustic data show how bubble plume variability is linked to the local tidal cycles. Photo and video imagery reveal how intense gas ebullition contributes to rapidly shaping the seabed morphology. This work is funded by the German Ministry of Education and Research (Bundesministerium für Bildung und Forschung). The OOI is funded by the National Science Foundation.

We studied seafloor characteristics, water column anomalies, and sediment methane geochemistry in the German sector of the central North Sea during a research cruise with the German research vessel Heincke in summer 2019. An extensive hydroacoustic mapping campaign revealed the presence and distribution of flares in the water column, indicative for gas bubble releases as well as for geophysical subsurface indications of elevated gas concentrations. We analyzed the spatial distances of detected flares to subsurface salt diapir locations, seismically identified gas accumulations, and abandoned well sites. Continuous and discrete measurements of dissolved methane concentrations in the water column support the identification of seepage from the seafloor. Our data demonstrate that dissolved methane concentrations in the upper water column were not enriched above the studied well sites. At one area, characterized by the presence of shallow gas pockets, we observed methane concentrations ten times enriched compared to background values close to the seafloor. Our results indicate an active natural seep system in the northwestern part of the German North Sea, which is related to updoming salt structures rather than leaking wells, and further underlines that natural seeps may challenge the identification of potentially leaking wells. Due to the shallow water depths of 30 to 50 m in the study area, at least part of the released methane is probably contributing to the atmospheric inventory. This conclusion is based upon our observations of flares reaching close to the sea surface and a slight oversaturation of surface waters in the flare-rich area.

The Mariana forearc provides a unique natural laboratory to study slab dehydration in an active subduction zone by its deep-rooted mud volcanism. To test if mantle wedge serpentinites would record the source fluid composition and thus the dehydration reactions in the slab, we investigated silicon (Si) isotopic compositions (δ³⁰Si) in serpentine veins by in-situ femtosecond laser ablation ICP mass spectrometry. Our samples were recovered during IODP Expedition 366 and originate from three mud volcanoes that root in different depths, so that the pressure/temperature conditions in their source regions vary.

The δ³⁰Si values differ strongly between the mud volcanoes but also between different serpentine generations within individual samples. Serpentine that formed under low water/rock ratios has δ³⁰Si similar to pristine olivine. In contrast, serpentine veins that formed under higher water/rock ratios show large ranges in δ³⁰Si that vary significantly but systematically between the mud volcanoes and thus with the metamorphic grade at depth. Average δ³⁰Si of such serpentine veins are ‑0.10 ‰, ‑1.94 ‰, and ‑0.80 ‰ to ‑0.93 ‰ with increasing depth-to-slab. We interpret these across-forearc changes to record the Si isotopic compositions of the fluid sources, that are at shallow depth (inferred slab temperatures of ~80°C) the dehydration of (biogenic) opal and release of pore fluids, at intermediate depth (~150°C) clay mineral breakdown, and at the deepest point (>250°C) decomposition of clay minerals and altered oceanic crust. These data imply that Si isotope signatures of wedge serpentinites can be used as a reliable proxy for slab dehydration processes.

Subduction is a key process for the plate tectonic cycle and is responsible for the bimodal composition of the Earth’ crust. Whereas active subduction zones can be directly observed at many places, their initiation and the early evolution of the associated volcanic arc can only be studied from the geological record. One key location to study the geological processes related to subduction initiation and subsequent arc emergence and maturation is the Izu-Bonin-Mariana (IBM) subduction zone system in the Western Pacific. Here, a unique record of rocks that formed during the earliest stages of the newly formed subduction zone are preserved in the forearc. However, much less was known about the spatial extent of these lithologies and thus the temporal evolution and the dynamics of subduction zone initiation in the IBM system. In 2014, IODP Expedition 351 added an important perspective by drilling in a rear-arc location, thus complementing the geological record across the proto-IBM arc. In this talk, I will provide a synthesis of the scientific achievements gained through this expedition. The technically challenging drilling recovered a 1.45 km-long section of hemipelagic and volcaniclastic sediments, and 150 m of oceanic igneous crust. New oceanic crust formed analogous to the so-called forearc basalts during subduction initiation, and age and composition of the basaltic crust allow us to constrain the dynamics of subduction zone initiation. The volcaniclastic sediments above provide us with important insights into the compositional and temporal evolution of the volcanic arc over its full lifespan.

The active volcanic arcs of the Scotia- and Caribbean Plate are two prominent features along the otherwise passive margins of the Atlantic Ocean, where subduction of oceanic crust is verifiable. Both arcs have been important oceanic gateways during their formation. Trapped between the large continental plates of North- and South America, as well as Antarctica, the significantly smaller oceanic plates show striking similarities in size, shape, plate margins and morphology, although formed at different times and locations during Earth’s history.

Structural analyses of the seafloor are based on bathymetric datasets by multibeam-echosounders, including data of GMRT, AWI, BAS, MARUM/Uni-Bremen, Geomar/Uni-Kiel and Uni-Hamburg. Bathymetric data were processed to create maps of ocean floor morphology with resolution of 150-250 meters in accuracy. The Benthic Terrain Modeler 3.0, amongst other GIS based tools, was utilized to analyse the geomorphometry of both plates. Furthermore, we used bathymetric datasets for three-dimensional modelling of the seafloor to examine large-scale-structures in more detail. The modelling of ship-based bathymetric datasets, in combination with the GEBCO 2014 global 30 arc-second grid, included in the GMRT bathymetric database, delivered detailed bathymetric maps of both areas.

With the help of the fine- and broad-scale bathymetric position index, we present the first detailed interpretation of combined bathymetric datasets of the entire Scotia Sea, the Caribbean and adjacent areas, such as the South Sandwich Plate. We identified typical morphological features of the abyss, based on determination of steep and broad slopes, ridges, boulders, flat plains, flat ridge tops and depressions in various scales.

The solitary intraplate volcano Vesteris Seamount is located in the Central Greenland Basin and rises around 3000 m above the seafloor with a total eruptive volume of ~500 km³. Newly acquired high-resolution bathymetry allows through backscatter data and raster terrain analysis to distinguish several volcanic structures. The Vesteris Seamount is a northeast to southwest elongated stellar-shaped seamount with an elongated, narrow summit radially surrounded by irregular volcanic ridges, separated by volcanic debris fans. Whole rock geochemical data of 78 lava samples form tight liquid lines of descent with MgO concentrations ranging from 12.6 to 0.1 wt. %, implying that all lavas evolved from a similar parental magma composition. Video footage from ROV dives show abundant pyroclastic deposits on the summit and on the flanks whereas lavas are restricted to flank cones and dike intrusions. The seamount likely forms above a crustal weak zone and the local volcanic stress field increasingly affects the constructive and destructive features on the surface. The evolution of Vesteris Seamount reflects the transition from deep, regional crustal stresses in the older features to local, volcanic stresses in the younger structural features. The Vesteris Seamount enables to understand the structural and magmatic evolution of intraplate volcanoes distant from plate boundaries by combining detailed geological sampling, high-resolution bathymetry and underwater video coverage.

The global objective of achieving net zero emissions is driving significant decarbonisation of energy and transport, with a shift towards renewable energy sources and electric vehicles. It is now widely recognised that this will drive significant increases in demand for a range of minerals and metals, including lithium, graphite, manganese, nickel and cobalt (used in batteries) and the rare earth elements (used in magnets in motors). There are concerns about the security of supply of some of these raw materials, and the increasing demand cannot be met solely by recycling; mining of primary resources will be essential. All of these raw materials can be derived from a range of geological sources, and many deposits are already known, but continued exploration is important. However, a range of other challenges can also impact the raw materials value chain; these may relate to mineral processing, social and environmental impacts, economics and politics. This talk will provide an overview of some of our recent and ongoing research on sustainable exploration, mining, and value chains for critical raw materials for the energy transition.

Epidosites are a prominent type of subseafloor hydrothermal alteration of basalts in ophiolites and Archean greenstone belts, showing an end-member mineral assemblage of epidote + quartz + titanite + Fe-oxide. Epidosites are known to form within crustal-scale upflow zones and their fluids have been proposed to be deep equivalents of ore-forming, black-smoker seafloor vent fluids. Proposals for the mass of fluid per mass of rock (W/R ratio) needed to form epidosites are contradictory, varying from 20 (Sr isotopes) to > 1000 (Mg mobility). To test these proposals we have conducted a petrographic, geochemical and reactive-transport numerical simulation study of the chemical reaction that generates km³-size epidosite zones within the lavas and sheeted dike complex of the Semail ophiolite, Oman. At 250–400 °C the modelled epidosite-forming fluid has near-neutral pH, it is highly oxidized and has low S and extremely low Fe contents. These features argue against the proposal that epidosite fluids are equivalents of black-smoker fluids. The Semail epidosites formed by replacement of lavas already altered to albite–chlorite–actinolite (spilite) assemblages, with the rare end-member epidosites requiring enormous W/R ratios of 700 to ~40000, depending on initial Mg content and temperature. Thus, the variably altered Semail epidosite zones record flow of ~10¹⁵ kg of fluid through each km³ of precursor spilite rock. This fluid imposed on the epidosite an Sr-isotope signature inherited from the previous rock-buffered chemical evolution of the fluid through the oceanic crust, thereby explaining the apparently contradictory low W/R ratios based on Sr isotopes.

The distribution of permeability in the upper oceanic crust controls hydrothermal circulation and the water–rock interactions that feed seafloor mineralization. A prevailing view is that lavas behave as fractured aquifers whose permeability is dominated by major extensional faults flanked by damage zones. Comparatively little is known about the permeability of the km-wide blocks of crust that lie between major faults, yet such blocks constitute huge sources of leachable metals. Our field mapping of hydrothermal veins and pervasive alteration in spreading-axis lavas in the Semail ophiolite enables quantification of the permeability of distal blocks. Fracture length intensities are only ~0.005 m per m² of outcrop, an order of magnitude lower than in major fault zones. Laboratory measurements show the rock-matrix permeability of lava outcrops is ~2.5 x 10⁻¹⁶ m². Numerical hydraulic simulations using dfnWorks software yield bulk permeability of ~5 x 10⁻¹⁶ m² when flow through the fracture network and the rock-matrix are coupled. This demonstrates that the rock-matrix is as permeable as the sparse and unconnected fracture network, consistent with the thoroughly pervasive, rather than fracture-controlled, nature of greenschist-facies hydrothermal alteration observed in the distal Semail lavas. Our observations and calculated bulk permeabilities provide an updated view of fluid flow through the upper crust, in which matrix-flow controls circulation through large blocks of lavas, enhanced by fault-damage zones at km-scale intervals. This new perspective explains how the rock matrix in oceanic lavas is accessible for leaching of metals for seafloor sulphide deposits.

The Troodos ophiolite hosts significant Volcanogenic Massive Sulfide (VMS) systems, well-known as Cyprus-type sulfide deposits. They are mafic type VMS deposits, mainly enriched in copper and zinc and they have been deposited from seawater derived-hydrothermal fluids. Along the Troodos ophiolite, the VMS system is covered by thick, Fe- rich altered caps, known as gossans, which are likely due to weathering of the VMS under oxidizing conditions. However, the conditions for their formation remain largely debated, suggesting either a submarine weathering origin or mineralization weathering on land. Gossans represent a valuable part of the Troodos ophiolite, presenting not only significant amount of extractible copper and zinc, but also, gold and silver. The studied gossans present as mineral assemblage: goethite, jarosite, hematite, alunite, silica, clays, anatase and siderite. Magnetite, ilmenite and gypsum occur as accessory phases. In this study, we show combined data of Cu, Zn and Fe isotopes from three different mines of the Troodos ophiolite (West Apliki, Skouriotissa and Agrokipia), which indicate δ⁶⁵Cu values varying from -3.55 ±0.01‰ to -0.05 ±0.02‰ and δ⁶⁶Zn values ranging from -1.24 ±0.02‰ to +0.34 ±0.05‰. In addition, δ⁵⁶Fe values vary from -0.65 ±0.07‰ to +0.80 ±0.02‰. We aim to investigate the debated origin of the Troodos ophiolite gossans influenced by physicochemical conditions, fluid composition, hypogene ore (e.g., pyrites) and examine the supergene weathering process in VMS systems, based on the redox-sensitive behavior of Cu and Fe, as well as the pH-sensitive behavior of Zn in supergene-weathering environments.

Molybdenum isotope ratios (δ^98/95Mo) of marine sediments constitute an important tracer for paleoredox reconstructions of the ancient ocean. Due to its redox-sensitivity, significant mass-dependent Mo isotope fractionation is induced in present-day low temperature environments leading to distinct Mo concentrations and isotope compositions in different marine lithologies. Subduction and recycling of such fractionated material can thus be potentially traced in arc magmas. Indeed, Mo isotope variations are observed in mafic arc lavas that are attributed to reflect recycled crustal components, but open questions remain to what extent different subducted lithologies contribute to the Mo isotope signature of arc magmas.

We present a comprehensive Mo isotope dataset covering input to output at the Tongan subduction zone, together with exhumed eclogite-facies oceanic crust and sediments from the Western Alps and Alpine Corsica. Pelagic Mn-rich metapelites and MORB-type eclogites reveal that Mo is largely lost during early subduction metamorphism. Moreover, rutile hosts most of the remaining isotopically light Mo in the slab at higher metamorphic degrees where it remains fixed during slab-dehydration processes at subarc depths. Thus, direct recycling of this fractionated material cannot account for the observed positive covariations of Mo/Ce and δ^98/95Mo with fluid indices (e.g., Ba/Th) in Tongan arc lavas. We propose that Mo systematics in Tongan arc lavas are the result of shallow fluid-induced Mo mobilization and forearc mantle serpentinization during early stages of subduction. Subsequent mechanical transport and devolatiziation of this metasomatized forearc mantle material towards subarc regions is a plausible alternative process to recycle Mo and other metals.

Volcanogenic massive sulphide (VMS) deposits have been recognized both in fossil and present-day settings (e.g. mid-ocean ridges (MORs), back-arcs, island-arcs, fore-arcs) and are associated with different lithologies leading to variable metal enrichments. More recently, a sub-type of VMS associated with ultramafic rocks has been discovered at MORs. These ultramafic-hosted VMS (UM-VMS) form in genetic relationships with detachment faults exhuming mantle rocks and are commonly enriched in base (Cu, Zn, Ni), critical (Co) and precious (Au, Ag) metals. However, they are thought to be scarce in the geological record since they are unlikely to obduct from MOR settings.

We propose, based on an extensive review of worldwide UM-VMS deposits described in ophiolites, that this scarcity is only apparent. Previously, UM-VMS have been commonly misclassified for three main reasons: i) the tectonic settings in which they form has been misinterpreted (e.g. tectonic mélanges), ii) their origin may be disputed (hydrothermal vs. magmatic) and iii) orogenic-related metamorphism and deformation locally obliterated seafloor-related mineralogical and structural features. Also, the strong focus on UM-VMS formed in MORs prevented to recognize them in other settings such as ocean-continent transition or supra-subduction zones which are more easily preserved in the geological record. Here, we discuss discriminant features applied to fossil UM-VMS worldwide which allow us to classify them as such. We show that UM-VMS are not as scarce as previously thought and, hence, represent possible undiscovered metal resources. Further genetic and exploration models are needed for new discoveries.

Mid-Oceanic ridges are places of intense fluid-rock interactions. At (ultra)slow-spreading ridges where mantle rocks are exhumed along detachment faults, this notably leads to the formation of mineralized systems. They commonly form massive sulphides at the seafloor which are enriched in base (Cu, Zn, Ni), critical (Co) and precious (Au, Ag) metals. However, the limited conditions of observation at the seafloor lead to partial rather than integrative understanding of these hydrothermal systems, especially concerning deep hydrothermal processes. Alternatively, the study of fossil analogues preserved on-land offers the opportunity to study these systems in 3D and to access the deep hydrothermal plumbing system of such mineralizations.

We adopted this strategy here and focused on a mineralized system preserved in the Platta nappe (SE Switzerland), a remnant of the Jurassic opening of the Alpine Tethys Ocean. As a rule, the hydrothermal system escaped strong Alpine overprint. In the Platta nappe, detachment faulting led to mantle exhumation against basalts. Associated HT fluid circulations led to the formation of mineralizations in the serpentinized footwall at the lithological interfaces with mafic intrusive rocks, suggesting the latter acted as preferential pathways for fluid flows. The Cu-Fe-Co-Zn-Ni mineralization forms massive, semi-massive sulphides and stockwork structures. It mainly consists of chalcopyrite, pyrrhotite, pentlandite, isocubanite and magnetite associated with Fe-Ca-silicates (ilvaite, hydro-andradite and Fe-diopside). Based on structural and petrographic features, the hydrothermal system of the Platta nappe is inferred to represent the root zone of present-day hydrothermal systems.

Groundwater quality degradation is a well-recognized phenomenon and has received considerable attention since the industrial revolution. In spite of this, many aspects concerning the understanding and management of groundwater as a resource remain complex, and adequate information, in many cases, remains elusive. Strategies to protect and manage groundwater quality are often based on limited data and thus restricted system knowledge.

As questions remain about the behaviour and prediction of well-known groundwater contaminants, new concerns around emerging contaminants are on the increase. In urban, industrial and agricultural areas especially, groundwater quality is widely compromised by anthropogenic impacts. Water management in such areas is recognized as a very complex task, in terms of different spatial and temporal scales, as well as understanding the input mechanism, transport and attenuation processes: crucial for sustainable groundwater management. The residence time of contaminants within groundwater bodies can be anywhere from weeks to decades, depending on physico-chemical properties of compound and environmental conditions. It is therefore well-accepted that subsurface heterogeneity necessitates the application of multiple tracers and methods to minimizing uncertainties and to uncovering subsurface processes that would not have been identified by the application of e.g. only one tracer. Thus, although contaminants are typically unwanted, they can provide crucial insights into flow and transport processes within aquifers.

This presentation highlights some of the key contaminants that originate from anthropogenic activities, reviews some of the major controls on groundwater contamination, and includes a case study that addresses historic and emerging issues in contaminant hydrogeology.

Emerging micropollutants such as lifestyle drugs, pesticides, and pharmaceuticals are increasingly detected in the aquatic environment. To counter possible threats posed by these pollutants, their transport behaviour needs to be thoroughly understood.

In this study, 22 laboratory column transport experiments were conducted at selected pH and Na⁺ concentrations with natural quartz sand as sorbent to determine transport behaviour of the beta-blocker metoprolol (MTP, pK_a=9.67) at various conditions. MTP breakthrough curves were measured at pH 3, 6, and 11, as well as NaCl concentrations of 1, 10, and 100 mM/l to account for coupled effects. The observed mean R ranges from R=1.04 (pH 11; 100 mM/l NaCl) to R=10.5 (pH 5.6; 1 mM/l NaCl).

An ion exchange equation was used to model CEC and exchange coefficients of Na⁺, H⁺ and MTP using a least square refinement routine considering the whole dataset of 43 retardation values.

With the model, a high R-regime at low cation concurrence (c(NaCl)~1 mM/l) and neutral pH (5<pH<9) could be identified. Decreasing of retardation can be attributed to: (1) increasing Na⁺ concurrence, (2) decreasing pH at pH<5 due to lowered zeta potential and i.e. negatively charged sites covered by H⁺, and (3) increasing pH at pH>8.5 as a result of changing MTP speciation.

Nitrate is one of the dominant chemical pollutants of groundwater, and there is a need to mitigate groundwater pollution in rural, urban and industrial terrains in an aquifer system. The study assesses the extent of nitrate pollution in the Densu Basin because of its predominance in agriculture and urbanized vicinities by employing robust techniques for estimating both the natural background and human-induced concentrations. The statistical methods used to estimate these concentrations are the pre-selection method, graphical approach (probability plot),non-parametric approach (kernel density estimation), and parametric approach (Gaussian mixture model). The study shows that the Gaussian mixture model is robust enough in determining the spectral distribution and clustering of the nitrate concentration in the basin. It estimated the natural background and human-induced concentration at1.7±1.3 and 9.8±5.6, respectively. The results show that the natural background concentration in the basin is more dominant and hence, conducive for drinking. Also, we show that26%of anthropogenic sources have leaked into the natural groundwater of the Basin. The data suggest that the nitrate concentration in the Densu aquifer system is sourced from agricultural input, domestic effluent and atmospheric deposition. High nitrate loading was observed in areas of active agricultural activities (Suhum, AkwapemNorth, Ayensuano and Upper West Akim). These areas should be protected from further anthropogenic exposure

The identification of contamination sources is vital for water protection, especially in highly vulnerable karst aquifers. Contamination sources might be distinguished by host-specific DNA markers of bacteria (Microbial Source Tracking, MST) or source-specific indicator compounds (Chemical Source Tracking, CST). These methods can help to identify a type of contamination source but fail to distinguish similar contaminant signals from different origins, e.g. multiple points of wastewater infiltration. Transport modelling can reduce these ambiguities by considering the time course of contaminant concentration, thereby allowing for a better allocation of the input source. However, flow in karst aquifers is highly heterogeneous and very dynamic. Hence, distributed numerical transport models on catchment scale are complex, difficult to parameterise and suffer from manifold ambiguities.

Here, an approach is presented, which aims at improving identification of contamination sources by combining MST/CST with transport modelling. Fast (conduit) transport is represented by a 1-D problem and a maximum transport distance for contamination events is modelled. The model is based on (semi-)analytical solutions of transport models, well-established in tracer test analysis to estimate apparent tracer velocities. In this study, a-priori knowledge about velocities and input times is used to inversely model transport lengths from contaminant breakthrough curves.

The inverse transport model (implemented in GNU Octave) was validated and parameter sensitivities were analysed. The maximum transport distance approach was shown to perform well during periods of flow recession. It was applied successfully to a contamination event at a karst spring and allowed for assigning its input to a stormwater tank.

In alpine regions, karst springs are important sources of drinking water but highly vulnerable to temporary contamination, particularly in response to rainfall events. This variability of water quality requires rapid determination methods of contamination parameters. In this study, we present a multi-parameter approach to determine the dynamics of fecal bacteria, organic carbon and particles at alpine karst springs.

Conventional cultivation-based analysis of fecal bacteria such as E. coli is time-consuming. The measurement of the enzymatic activity of E. coli could prove to be a valuable tool for water-quality monitoring in near real time. We used an automated device (ColiMinder) to measure β-D-glucoronidase (GLUC) at an alpine karst spring. To assess the relations between GLUC activity, discharge dynamics and contamination patterns, multiple hydrochemical, physicochemical and microbiological parameters were measured in high resolution. We observed strong correlations between small particles (1.0 and 2.0 µm), conventional E. coli results, ATP measurements and total organic carbon. These parameters also show strong and significant negative correlations with the electrical conductivity. At high contamination levels, GLUC activity also reveals good correlations with E. coli and small particles.

The results demonstrate that the investigated karst springs showed fast and marked responses of all investigated water-quality parameters to rain events. At high contamination levels, GLUC and particle-size distribution are suitable parameters for the rapid assessment of bacterial contamination in high resolution. While GLUC activity alone cannot substitute conventional determination methods, a combined use of these parameters is a promising approach for an early-warning system regarding bacterial contamination.

Public access to geological data, especially to data from commercial subsurface geological investigations, was claimed for a long time in the German geoscience community. Since June 30^th 2020, the Geological Data Act (Geologiedatengesetz, GeolDG) regulates the public availability of this data and replaces the Mineral Act (Lagerstättengesetz) from 1934. The GeolDG implicates both duties for persons who carry out or commission geological investigations and for the competent authorities, which are Geological Surveys. The “Landesamt für Bergbau, Energie und Geologie” (LBEG), as the Geological Survey of Lower Saxony, currently designs a digital application to organize the entire notification, data management and administration procedure, including the processes of registering geological investigations, of transmitting geological data, of generating administrative decisions, and of releasing data to the public according to the given regulations and deadlines. The current online application for registering boreholes, the “Norddeutsche Bohranzeige Online”, will be adapted and implemented into the new system. Following the legal guidelines, further categories will be other site-specific geological investigations such as outcrop studies or examinations of mining sites, investigations of areas or transects such as field mapping or geophysical surveys, and re-investigations of existing geological data such as geological models or reports developed from publically available data. One objective of the new application is to enable users to correctly notify the LBEG about any kinds of geological investigations, to retrace their own notifications, and finally to upload the geological data in the requested data format.

In 2014, an analysis showed that EU had funded geoscientific data harmonisation projects with several hundred thousand Euros but that only a small fraction of the results were sustained a few years after the projects ended. EuroGeoSurveys therefore decided to establish the EGDI which was first launched in 2016. This version consisted of a web GIS, dedicated GIS viewers for specific geoscientific topics, numerous distributed web services, a metadata catalogue, a database for pan-European harvested data, and it gave access to over 600 layers from 13 projects.

EGDI provides a pipeline of data and knowledge through which the geological surveys connect strategically and technically with the wider European Research and Digital landscape.

In 2018, the Horizon 2020 ERA-NET GeoERA was launched with 14 projects, all of which generate large amounts of pan-European and cross-border data sets. EGDI is the platform to safeguard, harmonise and disseminate all this information. Through a dedicated project (The GIP-P), EGDI is being substantially extended with a document repository, a search system, a 3D database, vocabularies, a user support system and eLearning platform, etc. When GeoERA ends in October 2021, EGDI will give access to results from a total of 37 projects covering on- and offshore geology, raw materials, geoenergy, groundwater, geohazards, geochemistry, and geophysics.

Future plans focus on further developing EGDI under a Horizon Europe Coordination and Support Action where EGDI will move towards becoming a knowledge infrastructure.

The presentation will explain about the system, the challenges and lessons learned from the last 5 years.

Since 2019, the LGRBwissen internet portal provides freely accessible and reviewed geoscientific information for the state of Baden-Württemberg. With LGRBwissen, the State Office for Geology, Natural Resources and Mining (LGRB) is expanding its product portfolio with supplemental descriptions of digital geoscientific data (GeoLa). Although LGRBwissen is primarily designed for professional customers of the LGRB, easily understandable information for the interested public is offered in several sections.

The core of the portal is a tripartite search tool. Besides using a free text search, it is possible to filter thematically by subject and to search spatially. The spatial search is possible by digitizing a polygon in a map application or by entering a location name directly. The latter opens a list with pre-configured administrative units, such as municipalities or districts.

In the central part of each page, there is an interactive map with an overview of the specific geoscientific topic described. The map navigation follows established internet standards. The level of generalisation is automatically depending on the map scale. In addition to the geoscientific descriptions, LGRBwissen contains a geoscientific glossary, picture galleries, links to the detailed information about the mapping units and further publications of the LGRB downloadable as PDF files.

As a modern and attractive tool, LGRBwissen has significantly improved the knowledge transfer from the LGRB to its customers. Furthermore, the interdisciplinary linkage of contents creates numerous synergy effects for administration, science, education, and business.

LGRBwissen can be reached at https://lgrbwissen.lgrb-bw.de.

Due to constantly changing requirements and needs for easy access and use of geoscientific data, the technology and methods to provide and present this type of data have recently evolved remarkably and will undergo more changes in the time to come. The aim is to address broader user groups in addition to the original group of experts ranging from non-experts to even the public to support decision making and participation in projects and initiatives.

What used to be classical data portals providing purely access and download of data or consumption of data services will be supplemented with more ways to explore and analyze data in focused apps right away without switching to expert tools. New and tailored visualizations allow users with specific backgrounds to make better decisions and draw the right conclusions within the context needed.

More and more, new data hubs and federated portals and platforms in the cloud or on premise allow collaboration between different domains. Direct connections and interfaces between these domains nurture integrated and interdisciplinary value chains. Focused apps such as dashboards and storymaps support new experiences of data.

The lecture gives an overview and shows existing examples of these new offerings including the geological domain

The presentation of 3D-data is gaining a crucial role for the government agencies in Germany. With the introduction of new federal laws on data storage and release, it became important to present 3D-data in an accessible way to everyone. Since the general public can handle web browser applications easily, unlike desktop applications, web-based technologies should be implemented for data presentation. A good user experience and a valuable access to the data requires that a number of components within a web technology need to work together in both back end and front end.

A 3D-viewer with web technology requires minimum configuration to run. Any web application has standard technologies like programming languages PHP, .Net 5 or JavaScript, a descriptive language HTML and a hosting server with a particular software environment (LAMP). In addition, to visualize the 3D-data, it is necessary to integrate a 3D-engine, e.g. WebKit, and optimize data transfer between a database and a client. However, there are limitations of 3D-data presentation with web applications. For example, a 3D-engine retards performance and interaction with users.

We have implemented full stack components of a 3D-viewer with developed web technologies for our own NIBIS3D-viewer at the State Authority for Mining, Energy and Geology of Lower Saxony. In our work, we show that these 3D-viewer components comprise a good running system for the visualization of 3D-data and represent a complete infrastructure from server over back end to front end interfaces for users.

More than 15 years ago the geographical information system GisInfoService was implemented as part of the project ‚GeoRohstoff‘ of the former Commission for Spatial Information Economics (GIW-Kommission). Sponsored by the German Aggregates Associations the purpose of this web application has ever since been to provide the companies of the quarrying industry with relevant spatial information, such as aerial photography, geological and hydrological data or information about land use or conservation areas. Fast access to these facts is fundamental not only for planning processes but also for everyday tasks and the quick generation of maps for presentations.

GisInfoService makes use of the infrastructure for spatial information that has been built up in the last one and a half decades. It integrates official data by means of web map services published by public authorities (e.g. land surveying offices or geological surveys). If required, there is the option to expand the mere web viewer of GisInfoService by combining it with a data warehouse that contains operational data such as quarry development plans or information on land property, lease, contractual terms or quarry permits.

Presenting the geoportal GisInfoService should give an example how geoscientific data and other public sector information is used by German quarrying companies and their associations for their purposes.

Historically, basin and petroleum system modeling has mainly focused on understanding the burial and thermal history of sedimentary rocks as well as related hydrocarbon generation from kerogen (sedimentary organic matter) in source rocks; much less studies treated hydrocarbon migration and accumulation in great detail, although it is of uttermost importance for petroleum exploration and production. New 2D and 3D basin models in different parts of the Persian Gulf indicate the variable complexity of hydrocarbon migration in this region. A complex migration pattern including sequential filling, spilling and refilling of the structures are assumed for the northern part of the basin, whereas in the southern part simple lateral migration over distances of hundreds of kilometers is reasonable. Besides geometry of the basin, tectonic evolution of structural highs and facies variations are the controlling parameters on the direction of hydrocarbon migration and accumulation in the northern part. While there is a presumably minor effects of the fault systems on the burial and thermal history, their role as hydrocarbon conduits and therefore controlling the hydrocarbon accumulation and geochemical properties are of great importance. The results provide key information on charge history and understanding of the Cretaceous-Tertiary petroleum systems and genetic distribution of oil families in the Persian Gulf. It also reveals the possible causes of exploration failures and hints for future hydrocarbon exploration potential.

Organic matter rich rocks are the main component of any petroleum system. Marine organic matter deposits form a major part of these rocks and are the source of most oil. Vertical and lateral heterogeneities in marine petroleum source rocks are widely observed and owed to the dynamics of deposition and preservation of marine organic matter. Such source rock heterogeneities add major challenges to hydrocarbon exploration and estimation of resources, therefore, quantification of source rock potential using numerical prediction tools can contribute significantly to reducing exploration risks and enhancing the accuracy of resource assessment.

We introduce here our innovative approach to modelling marine petroleum source rocks as part of an established forward stratigraphic modelling workflow. This enhanced workflow only requires minor additional input to a regular forward stratigraphic model in order to simulate marine source rocks deposition and preservation. Modelled source rock properties with this method include TOC, HI, thickness, net to gross, lithology, and other depositional environments properties allowing a sound source rock potential assessment.

Additionally, we assess uncertainty, sensitivity, and risk on source rock potential using an innovative response surface modelling approach which provides an efficient and effective way to understand the controls on any output property and quantify the associated risk.

To illustrate this new methodology, we will present the case of the Mesozoic Carson Basin offshore Newfoundland and Labrador, Canada.

Any attempt at modelling natural phenomena includes a number of numerical assumptions on which we have little or no constraints. Basin and forward stratigraphic modelling are methodologies that aim at reproducing the history of sedimentary basins and their internal complexities. As are all deterministic models, these models are characterized by the none-uniqueness of their results. Meaning very different models can equally honor the calibration data. The traditional approach to such a problematic is a Monte-Carlo approach which requires running 100s or 1000s of simulations in order to capture the uncertainty and quantify the risk on an output of interest (e.g. Source rock maturity, charge, source rock presence, reservoir presence…). Such a large number of simulations requires days or weeks of computation and is thus not suitable for the operational needs of the industry.

In this presentation we will introduce an innovative approach for an efficient and effective sensitivity and risk analysis using response surface modelling. This method requires a small number of simulations, out of which a response surface can be constructed to mimic the behavior of the calculator. The predictivity of the response surface is checked with confirmation runs. The response surface can then be interrogated and producing thousands of results instantly for a thorough and quick sensitivity and risk analysis.

This method can be applied to basin and forward stratigraphic modelling and the analysis can be done on maps (whole model or per interval), along planned well paths (vertical or deviated), and in scalar mode.

The Böllstein Odenwald is forming a large anticline of mainly pre-Devonian rock in the Mid-German Crystalline Zone (MCGZ). The contact between core and schist envelope of the anticline is well exposed at Weichberg quarry. Metasedimentary rocks of the schist envelope are intruded by granodioritic sills of a Silurian magmatic arc, showing at least two folding phases: Recumbent tight isoclinal folds are overprinted by upright gentle folds. A pegmatite dike, intruding at 411 ±2 Ma (U-Pb analyses on zircon) into the schist envelope rocks, crosscuts perpendicular to the main foliation. It shows only a weak schistosity related to the isoclinal folding, which therefore must have been active in Lower Devonian (>411 ±2 Ma; Lochkovian/Pragian) after the Silurian intrusion of the granodiorite sills (U-Pb on zircon ca. 423 Ma, Dörr et al. in press). The Lower Devonian deformation of the East Odenwald probably results from the collision of the MGCZ with the NW boundary of the Saxothuringian Zone.

The core is represented by a (meta)granite intruding into the schist envelope at 404 ±2 Ma (U-Pb method on zircon). A deformed fold directly at the contact between metagranite and metasediments and dikes terminated at the contact point to eastward directed tectonic movements between core and schist envelope after 404 ±2 Ma, probably at 375 Ma (U-Pb on zircon, Todt et al. 1995). These results are compared to other units occupying a similar position in the European Variscides and help to clarify the position of the East Odenwald during Variscan orogeny.

Here we investigate the thermal structure of the lithosphere in the Alpine-Mediterranean region. We focus on areas characterized by negative velocity anomalies according to a lithosphere-upper mantle surface-wave tomography study (El-Sharkawy et al., 2020) to analyze possible lithospheric thinning and melting. Surface-wave, phase-velocity curves were determined by interstation cross-correlation measurements and inverted for a set of phase-velocity maps, spanning a broad period range. We invert fundamental mode Rayleigh and Love dispersion curves together with surface elevation and heat flow for the 1D thermochemical lithospheric structure in 13 columns. The inversion is framed within an integrated geophysical-petrological setting where mantle seismic velocities and densities are computed thermodynamically as a function of the in situ temperature and compositional conditions (Fullea et al., 2021). We analyze the presence of small amounts of melt in the vicinity of the lithosphere-asthenosphere boundary. We conduct sensitivity tests to asses the uncertainties associated with alternative experimental results accounting for the effect of melt and water on seismic velocities. Our results show that the lithosphere is thin (60-90 km) over the whole negative velocity anomaly area in the Alpine-Mediterranean region. We find the thinnest lithosphere in the Pannonian and Tyrrhenian basins (60-70 km), while the thickest lithosphere is located in the Iberia and Central Europe (80-90 km). Our thermal models show the presence of melting near the LAB (1300 ºC isotherm) in some of the columns (e.g. Pannonian and Tyrrhenian basins) associated with a pronounced drop in Vs velocities.

Recent evidence suggests that the Eifel Volcanic Fields (EVF) make measurable contributions to the surface deformation in GPS networks, but quantitative assessments of displacement time series and their impacts on long-term rates are lacking. The GPS sites in the EVF indicate anomalously slow uplift (up to 1 mm/yr) which stays at the limit of GPS sensitivity and noise level for monitoring crustal deformation in geophysical applications. Since the primary aim of existing geodetic GNSS networks in west Germany is positioning service for land survey engineering and transportation applications, many sites have been installed on inexpensive and non-geodetic monuments, thus highly vulnerable to disturbances resulting from monument instability and near-field multipath sources. These potential pitfalls have not been fully addressed in previous studies. Here, we reprocess all available GNSS observations (combined GPS and GLONASS observations) using precise point positioning technique and present precise analysis of displacement time series to generate reliable long-term rates and uncertainties. Individual time series is examined to determine local motion, non-linear deformation due to regional and local hydrology and site-specific noise.

Volcán de Colima is active andesitic stratovolcano in México located at the height of about 3860 m above sea level. It belongs to the Colima Volcanic complex within the Trans-Mexican Volcanic Belt. This volcano is characterized by intermittency of explosive and effusive episodes of volcanic eruptions. For 2007-2009 slowly extruded magma led to a lava dome formation and growth in the volcanic crater. In this work, we present two-dimensional numerical models of the lava dome growth, which have been computed on the KIT SCC bwunicluster using the Ansys Fluent software. The aim of the numerical study is to understand the link between the rheological properties of the lava dome and the morphological shapes of the dome. Numerical models of lava dome growth incorporate the crystal growth kinetics and the realistic topography of the crater floor. We consider several scenarios of dome growth with different conduit shape, initial and equilibrium crystal contents to analyze the model parameters controlling the morphology of the growing dome. The extrusion rate, the characteristic time of crystal content growth in lava, and the characteristic lava viscosity have been used as tuning parameters to optimize the difference between the morphological shapes of the observed and modeled domes. The numerical results show a good agreement with observations and allow constraining the viscosity of lava dome.

The culture around sharing our data and software is evolving. Funders are starting to provide more clarity and requirements. Institutions are working to provide support and incentives. And journals are requiring that data be cited with some improvement on software as well. And yet, it is still difficult. Not all data can be shared. Not all data can be cited.

As us celebrate our progress we must also strengthen our collaboration and efforts in addressing the current challenges and those to come. Achieving FAIR, open and reproducible research through data and software management and preservation is both difficult and rewarding. Governance and sovereignty as represented by the CARE Principles give us a framework to expand research stakeholders to the people and community. In this talk we will share approaches that the AGU is taking to share data and software with stakeholders of the research ecosystem for better science, decision-making, and transparency. Persistence is necessary. Flexibility is key.

NFDI4Earth addresses digital needs of Earth System (ES) Sciences (ESS). ES scientists cooperate in international and interdisciplinary networks with the overarching aim to understand the functioning and interactions within the Earth system and address the multiple challenges of global change.

NFDI4Earth is a community-driven process providing researchers with FAIR, coherent, and open access to all relevant ES data, to innovative research data management (RDM) and data science methods. The NFDI4Earth work plan comprises four task areas (TA), of which TA1 and TA2 are first introduced here:

TA1 2Participate will engage with the ESS community and secures that NFDI4Earth is driven by user requirements: Pilots, small agile projects proposed by the community leverage existing technologies and manifest the researchers’ RDM needs. The Incubator Lab identifies promising new tools and scouts for trends in ES Data Science. EduHubs produce open, ready to use educational resources on implementing FAIR principles in the ESS. The Academy will connect young researchers and their data-driven research to NFDI4Earth.

TA2 2Facilitate realizes the OneStop4All as the web-based entry point to FAIR, open and innovative RDM in ESS. It supports on how to find, access, share, publish and work with ES data. Specific user requests beyond the scope of the OneStop4All will be routed to a distributed User Support Network. TA2 will also unlock the wealth of data that exists in governmental data repositories and will collaborate with all services on supporting long-term archiving.

TA3 2Interoperate and TA4 2Coordinate will follow as a second abstract.

NFDI4Earth addresses digital needs of Earth System (ES) Sciences (ESS). ES scientists cooperate in international and interdisciplinary networks with the overarching aim to understand the functioning and interactions within the Earth system and address the multiple challenges of global change.

NFDI4Earth is a community-driven process providing researchers with FAIR, coherent, and open access to all relevant ES data, to innovative research data management (RDM) and data science methods. The NFDI4Earth 2021-26 work plan comprises four task areas (TA), of which TA3 and TA4 are finally introduced here:

TA3 2Interoperate aims at interoperability and coherence of the heterogeneous, segmented range of ESS RDM services. The ecosystems of ESS (meta-)data and software repositories, data science services and collaboration platforms get integrated iteratively into a common NFDI4Earth architecture. Based on commonly agreed-upon standards TA3 provide consistent methods for a self-evaluation of RDM offerings. TA3 works on NFDI cross-cutting topics and makes outcomes accessible as a Living Handbook. It ensures co-operation in international RDM initiatives and standardisation bodies.

TA4 2Coordinate facilitates the overall management of the NFDI4Earth consortium. TA4 acts as central support service and coordination of the technical implementations. It also offers virtual research environments. The NFDI4Earth Coordination Office will support the NFDI4Earth community in day-to-day operations and acts as the NFDI4Earth point of contact. It develops a commonly agreed model for a sustainable operation of NFDI4Earth.

A commonly accepted NFDI4Earth FAIRness and Openness Commitment is key to fostering a cultural change towards FAIR and Open RDM in the ESS community.

Digitalisation and FAIR data are overarching elements in the Helmholtz Research Field Earth and Environment (RF E&E) Program-Oriented Funding Phase IV (PoF IV). Already in the transition years from PoF III to PoF IV (2019/2020) different measures were implemented to facilitate this aim. One of them is the so-called DataHub, with the aim that all Earth System (ES) data that is generated by the RF E&E will be available as FAIR data via a common access point. To achieve this, three thematic SubHubs have been created: for atmospheric data (ATMO), for maritime data (MARE, also including DAM) and for terrestrial data (TERRA). The three SubHubs (ATMO, MARE, TERRA) are interlinked by thematic working groups and are continuously developed. In addition, the SubHubs are undergoing a continuous integration process that aims at a common access point and improved interoperability of data, products and services. Here, a presentation via web-based services will be available soon, with common thematic viewers that also provide stakeholder relevant products, in addition to the actual underlying data. The DataHub will be maintained and continuously developed as a long-lasting project that will also support aspects of the NFDI process in general and the NFDI4Earth in particular, thus benefiting the ES sciences in Germany in general.

Open data and open-source code are influencing each other: the availability of open data sparks new developments for data analysis and processing. Open-source codes on the other hand have the potential to show the value of open data. This symbiotic effect is well visible in the successful recent developments in the field of machine learning, which was strongly influenced by open data sets and benchmark tests, for example in the famous Kaggle competitions.

We outline here the evolving landscape of open-source software developments for (subsurface) geoscience applications. Our overview includes codes and software packages for processing of typical geological and geophysical data sets (borehole data, seismic data, wireline logs, geological maps, outcrop and laboratory data etc.), as well as packages for data processing, up to full 3-D geological modeling and geophysical inversion approaches.

The long-term maintenance of these packages is often a challenge, especially when they are developed in research projects. But a combination with open geological data has the potential to lead to transparent and reproducible decision processes, which are relevant in many cases where geological subsurface investigations are used for public decisions such as evaluating possible nuclear waste repository sites or for geothermal energy exploration.

A high number of 3d geological models are produced every year at mining companies, geological surveys, consulting offices and many other institutions. Many of these models are being created by different authors and usually have a slightly different purpose and need to meet different demands. Yet the underlying geology stays the same.

While the data providers can publish a variety of 2d data sets 3d are lacking behind. This leads to a loss of knowledge, e.g. when domain experts have been creating a particular 3d model and refined it over the years but also to the loss of investments. The whole creation process must be executed by a second modeler.

With a database for 3d models the existing and new models can organized in such way that they are centrally accessible. In a first step within the organization. In further steps models might be shared with a broader audience. A flexible data model should be easily applicable and allow to apply any metadata model to the data to make it even easier to find the desired data.

In order to not only act a data silo a management system should provide an API such that the data is interoperable and allows to implement any needed data format or moreover to reuse the data directly in different programs or scripts.

With GST its users are being enable to layout a foundation for a FAIR geological management solution and apply several layers to make 3d models easily accessible.

Several glacial ice advances shaped the present-day morphology of central Europe during the Quaternary. Two Pleistocene glaciations, the Elsterian and the Saalian stages, advanced as far as the north-eastern part of the onshore Netherlands. Remains of these glacial advances and retreats are deep erosional glacial valleys of the Elsterian glaciation and till sheets, glacio-tectonic ridges and glacial basins assigned to the Saalian complex.

In this study, we present the effects of sequential loading and unloading of ice sheets on the temperature distribution and rock properties of the subsurface using 3D basin and petroleum systems modelling in the northeast Netherlands. A 3D basin and petroleum systems model was set up, incorporating the Neogene to Quaternary Upper North Sea Group down to the Carboniferous Limestone Group, was used and extended to incorporate sequential loading and unloading of ice sheets in the Pleistocene.

Subsurface temperatures are decreased due to low ground and ice sheet base temperatures, with minimum temperatures observed at the beginning of a glacial stage. During an ice sheet coverage, the subsidence caused by loading leads to an increase in temperatures, therefore counteracting a low ice sheet base temperatures. Generally, a lower geothermal gradient is observed in the upper layers of the 3D model. Pore pressures build up during glacials caused by extra loading and then retreat to a pre-loading state with time, depending on the strength of ice loading, the depth of the layer, as well as the rock properties of the overburden.

The La Baja Guajira Basin (LBGB) is the primary gas-producing region of Colombia and represents South America's northernmost prolongation. This study presents an analysis of regional 2D-seismic reflection data of LBGB integrated with borehole and gravity information. The deepest basement in the study area occurs in the northwestern offshore. This depocenter is oriented NW-SE. In the basin, four fault groups occur: 1) NW-SE-striking basement normal faults; 2) strike-slip faults; 3) inverted normal faults, and 4) local thrust faults. Prominent bottom simulating reflectors (BSRs) are present in the NW deep-water areas.

2D gravity modelling was used to comprehend the basin's geometry and basement type. It indicates that the crust under LBGB is best simulated with rocks of continental nature. 1D petroleum system modelling was applied to reconstruct and evaluate the basin's burial and thermal history. Modelling results show that the study area experienced two episodes of rapid tectonic subsidence (lower Middle Miocene, Late Miocene). During the Lower and Middle Miocene, sediment input into the LBGB was from east to west. In the Late Miocene, the Andean uplift provided an additional and significant sediments contribution from the south. A period of erosion due to uplift is evident in the northern area between the uppermost Middle and Upper Miocene. From the Pliocene to recent, relative tectonic quiescence is observed. Sediments in well Mero-1 (southern offshore) were subjected to high temperatures causing Middle Miocene source rocks to reach maturation indicated by 0.69 %VRr values; however, greater depths and temperatures are required for hydrocarbon generation.

After implementation of the Repository Site Selection Act (StandAG) in 2017, the Federal Company for Radioactive Waste Disposal mbH (BGE mbH), as the German waste-management organization, started the site-selection procedure for a nuclear repository for high-level radioactive waste in Germany. On the way towards the repository site with the best possible safety, the site-selection procedure is required to be a participatory, transparent, learning and self-questioning process based on scientific expertise. With the Sub-areas Interim Report published in 2020, first results were presented, outlining sub-areas with favorable geological conditions in preparation for defining the site regions for surface exploration. The identified 90 sub-areas with favorable geological conditions cover approximately 54% of the area of Germany. Currently, one of the main tasks in the site selection procedure is to conduct the representative preliminary safety assessments for each sub-area.

Apart from the technical descriptions of the repository system, the geoscientific characterization and interpretation (Geosynthesis) of the host rock, the overburden and the geological processes serve as a basis for the safety assessment. The main character of the Geosynthesis is therefore to compile all geoscientific information, relevant to the safety of a repository. Additionally, we describe how the Geosynthesis could be used to identify potentially suitable areas within large sub-areas. These areas with the most favourable geological conditions will then be evaluated in more detail during the representative preliminary safety assessments.

Ultramafic-hosted mineralized systems commonly form massive sulphides at the seafloor which are enriched in base (Cu, Zn, Ni), critical (Co) and precious (Au, Ag) metals. In present-day settings, the limited conditions of observation at the seafloor prevents a complete understanding of these hydrothermal systems, especially concerning deep hydrothermal processes. A way to unravel deep hydrothermal processes that occur in these systems is to focus on fossil analogues preserved on-land which noticeably well crop out in mountain belts.

We adopted this strategy here and focused on a mineralized system preserved in the Platta nappe (SE Switzerland), a remnant of the Jurassic opening of the Alpine Tethys Ocean. The geometry and petrographic assemblages of the hydrothermal system, previously established, served as a base for the present study. We performed a geochemical tracing both on whole rocks and in-situ metal-bearing phases (sulphides and oxides) sampled at three distinct structural positions of the hydrothermal system. Among the geochemical tracers, Co, Ni and Se appear as good proxies to constrain hydrothermal processes. Indeed, at given structural position, the Co/Ni ratio increases in the most mineralized and altered sample suggesting this ratio is linked to the intensity of hydrothermal alteration. Also, towards the top of the system, a general trend showing respective decrease and increase of the Co/Ni ratio and of the Se content in metal-bearing phases was observed. The evolution of these geochemical tracers together with petrographic evidences supports a genetic model for the Marmorera-Cotschen hydrothermal system involving hydrothermal fluid progressively mixing with seawater.

Volcanogenic massive sulfide (VMS) deposits associated with mafic-ultramafic rocks show strong structural control and are located at or in the vicinity of low angle detachment faults such as oceanic core complexes (OCC) in mid-ocean ridge environments. These ultramafic VMS deposits are variably enriched in precious (Au-Ag) critical (Co) and the base metals Cu, Zn, and Ni but the source of the metals remains poorly known. The Troodos ophiolite, Cyprus, and the ODP Hole 735B on the Atlantis Bank are investigated to better characterize the source of metals and the deposit genesis. The ODP Hole 735B recovers gabbroic rocks down to 1508 meters below seafloor (mbsf) and shows evidence for high temperature hydrothermal alteration in the upper 250 mbsf. There the rocks are significantly depleted in Cu and S and primary magmatic sulfides are absent, implying efficient metal mobilization. Similarly, the Troodos ophiolite shows evidences for relics of OCC with seafloor-related high temperature hydrothermal alteration and associated massive sulfide mineralizations. Within the western Limassol Forest complex in the Troodos ophiolite, the Dhierna main shear zone separates serpentinized ultramafic rocks from sheeted dykes. Here, massive sulfide mineralizations enriched in As, Au, Co, Cu and Ni are observed and are characterized by pyrrhotite, pentlandite, chalcopyrite, cubanite and cobaltite. Additionally concentrations of Cu, Zn, Ni and Co in the peridotites decrease with increasing serpentinization towards the detachment fault also implying metal mobilization during hydrothermal alteration along the detachment fault.

With the establishment of the Research Center of Post-Mining (FZN) at the Technische Hochschule Georg Agricola University in Bochum in 2015, the development of an extensive archive for the systematic collection and evaluation of all post-mining related information began. In addition to the current collection of more than 4500 books and journals, over 1000 maps, as well as slides, photographs and lecture notes, a Thesaurus Post-Mining is currently being created.

The combination of historic data and modern geomonitoring techniques such as remote sensing via satellite and unmanned aerial systems, allows the contemporary handling of post-mining issues. Based in concepts of various mining companies an adjusted approach is currently developed to integrate the variety of different datasets within a spatial data infrastructure (SDI). All this information not only supports the researchers of the FZN in their work, but also creates transparency in dealing with the legacy of mining and its significance for the present and the orientation towards a more sustainable future in post-mining regions. The goal is therefore not only the ongoing digitization of existing materials, but also the creation of an open-access database on the subject of post-mining and the establishment of a server-based spatial data infrastructure for internal and external users. In the long run, this step will ensure a transdisciplinary and inter-institutional evaluation of spatial data, while the research results as well as the already existing historical information can be made easily accessible to the public within the framework of the EU INSPIRE directive.

Fluid-mediated mass transfer in subduction zones is crucial for chemical cycling on Earth. Particularly little is, however, known about such processes at shallow subduction levels.

We used thermodynamic models to reproduce the metamorphic history of ocean island basalt (OIB) clasts recovered from the Mariana forearc during IODP Expedition 366. The OIBs were subducted to ~30 km depth, metamorphosed/metasomatized, and subsequently recycled to the seafloor via mud volcanism (Fryer et al., 2020). The rocks exhibit K₂O contents (median = 4.6 wt.%) and H₂O (median = 5.3 wt.%) much higher than OIBs situated on the Pacific plate (Deng et al., 2021), suggesting that these have been added during subduction. This interpretation is in line with the presence of abundant phengite in the samples. Additionally, mass balance calculations point to the addition of SiO₂, and high Cs, Rb, Th, and U concentrations imply an uptake whereas low Ba and Sr contents indicate the removal of trace elements.

We show that the metasomatic change in composition and the formation of phengite can be explained by (i) the dehydration of altered oceanic crust releasing K₂O-rich fluids and (ii) the subsequent reaction of such fluids with OIB. These processes are predicted to initiate at temperatures of <200°C and pressures of <5 kbar.

Our study provides direct evidence for fluid–rock interactions and metasomatism in an active subduction zone. We demonstrate that mass transfer from subducted oceanic crust initiates at low pressure/temperature conditions. Subducted volcanics can hence undergo significant compositional changes even at shallow depths.

The panalpine project "DOVE" (Drilling Overdeepened Alpine Valleys), co-funded by the International Continental Scientific Drilling Program (ICDP), is drilling a series of overdeepened glacial troughs around the Alps that were formed by subglacial erosion during past glaciations.

In the northeastern section of the DOVE project, we (re)investigate the inneralpine basin of Bad Aussee (Traun glacier area, Austria), the subalpine basin of the Salzach Foreland glacier (Neusillersdorf, Bavaria), and the tongue basin area of the Pleistocene Isar-Loisach-Foreland glaciers (Schäftlarn). Depths of the inneralpine glacial erosion below Bad Aussee reach down to –400 m below sea level (the level of the Dead Sea in the Levant, the lowest part of today’s surface topography on Earth). 880 m of core material have been drilled into the basin and will be reinvestigated and physically dated by luminescence and cosmogenic isotopes.

In Neusillersdorf (Bavaria), we continue to study the basin infill of a branch basin of the Salzach Foreland glacier. We know from former dating attempts that sediments from the penultimate glaciation and older are available in the basin.

Finally, the sequence in former tongue basin area of the Isar Loisach Foreland glacier area, close to Munich, offers about 100 m of lake sediments, which are interpreted to contain sediments from Middle Pleistocene glaciations.

All available cores will be studied with state-of-the-art tools and methods in modern sedimentology and dating technics. Especially the combined investigation and interpretation of several drillholes will offer the opportunity to develop a modern reconstruction of past (Eastern) Alpine glacial environments.

The panalpine project "DOVE" (Drilling Overdeepened Alpine Valleys), co-funded by the International Continental Scientific Drilling Program (ICDP), is drilling a series of overdeepened glacial troughs around the Alps that were formed by subglacial erosion during past glaciations. The sedimentary fill of these troughs, consisting of multiple stacked and nested glacial sequences, provide the best archives of when and where glaciers reached the Alpine forelands. The combined data from all DOVE sites, comprising synchronous or asynchronous ice advances and ice extents in the different regions, will eventually provide a critical database to evaluate the various patterns in glacial-interglacial paleoclimates and landscape evolution back to the Mid-Pleistocene.

The Tannwald Basin forms a distal, overdeepened part of the Rhine glacial landscape, ca. 50 km north of Lake Constance, and has a maximum depth of 240 m. Core and flush drilling on the western flank of the basin began in April 2021 and reached the bedrock, i.e. top Tertiary Molasse, at a depth of 154 m. The glacial basin is filled by 100 m-thick fine clastics of the Dietmanns Formation (Hosskirchian – Rissian age). This is overlain by 42 m coarse clastics of the Illmensee Formation (Rissian - Wurmian age). We aim to chronologically date the sediments using borehole and core geophysics, OSL, pollen, and noble gases from pore water. Together with detailed sedimentology, these data will be used to constrain the glacial history of the basin. We show the preliminary results of the flush and core drilling, together with the borehole geophysics.

The panalpine project "DOVE" (Drilling Overdeepened Alpine Valleys), co-funded by the International Continental Scientific Drilling Program (ICDP), is drilling a series of overdeepened glacial troughs around the Alps that were formed by subglacial erosion during past glaciations. The sedimentary fill of these troughs, consisting of multiple stacked and nested glacial sequences, provides the best archives of when and where glaciers reached the Alpine forelands. The combined data from all DOVE sites comprising synchronous or asynchronous ice advances and ice extents in the different regions, will eventually provide a critical database to evaluate the various patterns in glacial-interglacial paleoclimates and landscape evolution back to the Mid-Pleistocene.

One of the DOVE sites drilled the overdeepened Basadingen Trough, located in Northern Switzerland, within the extents of several Middle-Late Pleistocene foreland glaciations of a lobe of the Rheine Glacier. The trough is a narrow, ca. 250-300 m deep structure that runs SSE-NNW, forming a so-far poorly understood, old overdeepened valley system that connected the present-day Thur Valley with the Rhine Valley – a connection that does not exist in the present surface morphology and that was probably only active during the Middle Pleistocene. New high-resolution 2-D seismic displays a detailed seismic stratigraphy with several depositional sequences, indicating that the valley fill consists of deposits from multiple glaciations, making the Basadingen Trough an ideal target for DOVE. We aim to establish a chronostratigraphic and sedimentological model to identify and understand the older glaciations that affected the Basadingen Trough and the Northern Alpine foreland in general.

The panalpine project "DOVE" (Drilling Overdeepened Alpine Valleys), co-funded by the International Continental Scientific Drilling Program (ICDP), is drilling a series of overdeepened glacial troughs around the Alps that were formed by subglacial erosion during past glaciations. The sedimentary fill of these troughs, consisting of multiple stacked and nested glacial sequences, provides the best archives of when and where glaciers reached the Alpine forelands. The combined data from all DOVE sites comprising synchronous or asynchronous ice advances and ice extents in the different regions, will eventually provide a critical database to evaluate the various patterns in glacial-interglacial paleoclimates and landscape evolution back to the Mid-Pleistocene.

In this context, we accomplished several seismic surveys at the Tannwald Basin and Basadingen Valley as well as the Lienz Basin. Deploying small-scale vibratory sources in vertical and horizontal orientations, we examined both P- and S-wave reflection imaging. We were able to image (1) the bedrock topography and (2) the interior of overdeepened valleys in high resolution in all investigated sites. Especially, the sedimentary succession and thickness of the deposits vary in detail across the sites. Even the infills of valleys in the same catchment area differ significantly (e.g. Tannwald Basin and Basadingen Valley in the Rhine Glacier arena). Nonetheless, foreland and intra-mountainous valleys show the same overall structure for each accumulation cycle (more or less from bottom to top: basal till, basin fines, fluvial deposits). As conclusion, a detailed seismic study of each overdeepened valley is mandatory for a comprehensive understanding of overdeepened structures.

Restricted basins, such as the Baltic Sea, are particularly affected by global warming, which leads to intensifying stratification, severe oxygen depletion and increasing water temperatures. This, in turn, results in significant and lasting ecosystem alterations. Sediment cores recovered during IODP Expedition 347 allow reconstructing such changes. We analysed Holocene sediments from the Landsort Deep (IODP Site M0063) using combined palynological and biogeochemical approaches to reconstruct palaeoclimate variations as well as ecosystem changes and to identify anthropogenic influences. Comparison of pollen data with organic-walled dinoflagellate cysts and other palynomorphs provides a direct land-sea comparison, while increasing palynomorph concentrations are indicative for dysoxic conditions and better preservation. Our results indicate particularly warm conditions (based on TEX₈₆) that are paralleled by high primary productivity (high TOC) and increased anoxia (low pristane/phytane ratios) around the Holocene Thermal Maximum (~7 to 5 kyr BP), Medieval Climate Optimum (~1 kyr BP) and Modern Hypoxic Period (since ~1950). For the late to middle Holocene (~7 to ~4 kyr BP), our data imply a decreasing brackish-marine influence until 4 to 3 kyr BP, accompanied by diminished aquatic primary productivity indicated by declining abundances of dinoflagellate cysts and an increase of the terrestrial vs. aquatic ratio (TAR_HC). Our data do not reveal equally strong terrestrial ecosystem changes until the past ca. 1000 years, which witnessed increased agricultural activity, implied by higher abundances of rye pollen as well as probably anthropogenically induced deforestation, implied by a relative decrease in non-saccate tree pollen and increase in non-arboreal pollen.

Understanding past variability and forcing of the Indian Summer Monsoon (ISM) is essential for better anticipating its behaviour under future climate change scenarios and the resulting consequences for the subsistence of a large part of the world’s population. However, long-term high-resolution proxy records of terrestrial hydroclimate variability from the ISM core zone are still relatively scarce. To reconstruct ISM variability and associated vegetation changes in northern India during the last ~75 kyr, we analysed the stable hydrogen and carbon isotope composition (δD, δ¹³C) of long-chain n-alkanes (n-C₂₉, n-C₃₁) from higher terrestrial plants that are preserved in marine sediments from IODP Site U1446 in the northwestern Bay of Bengal. Being located within the reach of several large rivers, this site is characterized by high riverine input of terrestrial organic matter and thus ideal for establishing representative records of past hydroclimate and vegetation changes on the northern Indian subcontinent. The obtained δD data reveal a stepwise ISM intensification at the last glacial-interglacial transition but also several distinct centennial- to millennial-scale reductions in ISM intensity during the last glacial period. These so-called Weak Monsoon Intervals (WMIs) occurred parallel to cold events in the North Atlantic realm, e.g. during Heinrich events H1, H2, H4, H5 and H6, pointing at a close hemisphere-scale climatic teleconnection between the North Atlantic and Asia. In contrast, hydroclimate-driven changes in vegetation composition during the WMIs – reflected by the δ¹³C data – were only very subtle, possibly reflecting a partial resilience of the vegetation during the last glacial period.

Most countries are by now committed to the Paris Agreement, which deals mainly with the reduction of greenhouse gas emissions and financing thereof. Crucial pillars driving this greenhouse gas diminution are renewable energies and e-mobility. As in any industrial revolution, this fundamental shift from “fossil energy” towards renewable energies and e-mobility, requires new technologies and associated new suite of raw materials, without which this shift will not be possible or at least significantly delayed.

Energy storage is one of the key challenges to a successful shift. One way to store energy are new generation batteries. The growing need for energy storage for e-mobility and other battery-intense applications has created a large interest in the key battery commodity Li as well as other critical raw materials like Ni, Co, Cu and graphite. Current forecasts assume that Li-ion battery technologies will be the prevalent battery technology for the foreseeable future. Public domain data suggest very significant increases in commodity demand, if 100 % e-mobility is to be achieved. Considering current market volumes, demands for Li and Co will increase far over 1500 %, while demands for REE and graphite will exceed 500 %. Demand on Cu will moderately increase. In contrast, need for steel and PGM may decrease.

This extraordinary strong growth of demands for these critical raw materials used in e-mobility have raised concerns regarding long-term supply. Exploration, mining and processing are challenged to adapt and to produce these commodities in order to achieve this new industrial revolution.

A 50-element stream sediment geochemistry survey with a sample density of one sample per km² shows anomalies for a number of high technology metals, including Sn, W and the battery metals Co and Li. Apart from the anomalies associated with known deposits, low-level anomalies of Li and Co are widespread in anchimetamorphic to greenschist facies metasedimentary rocks. Li anomalies are prominent in Phycoden Group phyllites in the Vogtland and parts of the Frauenbach and Thum Groups in the West Erzgebirge Transverse zone. Co is enriched in the Brunndöbra Subformation (Klingenthal Group) where it is probably associated with Besshi-type massive sulfide mineralisations.

We use self-organizing maps (SOM), a type of artificial neural network (ANN), for data analysis and data fusion with geophysical and structural-lithologic data to identify areas of interest for further exploration. Using known deposits as training data, the SOM-transformed data are converted to mineral predictive maps with a multi layer perceptron, a different type of ANN. This combined machine learning approach overcomes some of the problems in applying ANNs to mineral predictive mapping, in particular the problem of imbalanced training data.

The paper has been compiled in the frame of "NEXT - New EXploration Technologies" project. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776804.

Eastern Canada hosts several occurrences of lithium pegmatite, which have recently come into the focus of exploration activities and detailed studies. Driven by the current and expected future demand for Li, the mineral occurrences are targeted by exploration companies.

This area in Canada is currently in the focus for targeting the mineral occurrences of lithium pegmatite.

The majority of the pegmatite are hosted in metasediments or biotite-rich granite. In the more northern part the host rock becomes also greenstone. These pegmatite are very old up to 2.6 billion years old.

The latest update of the exploration data and statistical modelling combined with a more detail mine plan some new results will be presented for some of the Georgia lake pegmatite.

The lithium mineralisation in these pegmatite is in many cases the spodumen. This light green pyroxene is often bid as an finger and builds up to 20 % of the volume of the pegmatite. In addition, previous work also identified beryl, columbite, molybdenite, amblygonite, apatite, and bityite, enhancing the Li and rare metals potential of the area.

The pegmatite has different thickness and length. The bigger ones are up to a mile long and in some cases up to 20 m wide. Sometimes they split up in parallel dikes. The Li2O contend of the pegmatite varying from 0 up to 2,7 %. During the investigation some million tonnes of resources were defined with an average Li2O contend of around 1 %.

More than 70% of the global lithium resources are not solid minerals but dissolved salts within continental brines or geothermal waters. Critical issues in the exploitation of such deposit include low Li concentrations and high level of impurities that need to be discarded.

One of the most important methods for Li acquisition from brines is ion-exchange. In this perspective, the use of zeolitic materials as ion-exchangers in lithium extractions can potentially represent a fast and cheap alternative to traditional methods. In ion-exchange processes, the anionic charge of the host structure is compensated by Li⁺ cations. Because of the high charge density, the Li⁺ cations can interact relatively strongly with the host framework and therefore significantly distort it. We examined this effect at the atomic scale and highlight the structural distortion upon Li-exchange in vanadosilicate zeotypes. Using X-ray diffraction, we were able to precisely locate the Li cations within the framework and characterize the structure. Differences in the position and bond energy of the cationic sites strongly affected the extent and kinetics of the cation exchange. Thus, we observe Li⁺ exclusion at specific exchange sites. This appears to be directly linked to the coordination requirements of the Li-cations with the framework oxygen atoms. Our findings might contribute to a rational design and functionalization of zeolitic material to efficiently extract lithium from brines.

With a world-class graphite project in Tanzania (East Africa), The Pula Group, LLC is committed to a greener future. The high-quality graphite mineralization includes jumbo flakes developed to a depth of 60 meters, a key driver ensuring the project economics are strong. The Pula graphite deposits are extensions of the Nachu graphite deposits. PGP is taking a modular approach to mining and processing graphite, an innovative and efficient approach to optimize the success of the project during the ramp-up phase. This adaptive approach to mining helps mitigate economic risk and the "too big to fail" attitude that has sunk many large-scale mining projects. The PGP model provides a clear way to reignite the capacity for junior mining companies to activate the sector with minimal risk and maximum benefit to communities.

Along with the high caliber of its Tanzanian graphite opportunity, The Pula Group, a U.S.-based company, is setting high ethical standards in the mining sector. The Group's subsidiary for developing the project is Pula Graphite Partners (PGP), a 50-50 joint venture with local strategic partners. Even during the exploration phase, PGP already has a superior track record of philanthropy.

Reconstruction of denudation rates through time is an important task to quantify and understand the impact of climate on landscape evolution. Cosmogenic nuclides have been widely used as a tool to infer denudation rates at the watershed scale from both river sediments and past stratigraphic records. Here, we analyze the in-situ ¹⁰Be cosmogenic concentration over the last 75 ka in sediments cores that were collected offshore the Var River (Western Mediterranean Sea).

We present 26 ¹⁰Be paleo denudation rates ranging from 0.15 ± 0.01 and 1.26 ± 0.16 mm yr⁻¹. At the exception of the LGM period, the ¹⁰Be paleo denudation rates are similar to these of today in the Var (0.24 ± 0.04 mm yr⁻¹). However, during the LGM, paleo denudation rates were 2 to 3 times higher than today, suggesting that glaciers may have played a role. To investigate this sharp increase in denudation rates, we use a mass balance approach to differentiate the glacial from the fluvial component of denudation rates. The resulting average glacial erosion rate during the LGM is 1.5 (+0.9 / -1.0) mm yr⁻¹, roughly four times above the value of 0.4 (+0.4 / -0.5) mm yr⁻¹ obtained during MIS 3-4 (29 - 71 ka) Our data suggest that climatic variations may only strongly affect denudation beyond a certain threshold, probably controlled by glacier dynamics, the duration of glacial advances, and temperature-driven processes such as frost cracking. Our study indicates that the denudation response to Quaternary glaciations is complex and nonlinear in glaciated areas.

Debris-covered glaciers are fed from steep bedrock hillslopes that tower above the ice, so-called headwalls. Recent observations in high-alpine glacial environments suggest that rock walls are increasingly destabilized due to climate warming. An increase in debris delivery to glacier surfaces will modify glacial mass balances, as surface debris cover impacts on the melt behavior of the ice underneath. Consequently, we expect that the response of debris-covered glaciers to climate change is likely linked to how headwall retreat responds to climate change.

As debris is deposited on the ice surface along the sides of valley glaciers it is passively transported downglacier on and in the ice. Where glaciers join it is merged to form medial moraines. Due to the conveyor-belt-nature of glacier ablation zones, debris tends to be older downglacier and, hence, systematic downglacier-sampling of medial moraines holds the potential to assess rates of headwall retreat through time.

In order to quantify headwall retreat rates, we measured the concentration of in situ-produced cosmogenic ¹⁰Be in debris samples collected on downglacier profiles along parallel medial moraines from a partly debris-covered Swiss glacier. Our results indicate that indeed nuclide concentrations along the medial moraines vary systematically, being higher for older downglacier deposits and lower for younger upglacier deposits. This variation cannot be explained by additional nuclide accumulation during transport alone. Instead we propose that ongoing ice cover retreat across deglaciating headwalls since the end of the Little Ice Age and the exposure of newly eroding bedrock surfaces may explain recently decreasing ¹⁰Be concentrations.

Quantifying carbonate denudation and the partitioning between chemical and mechanical surface lowering in karstic areas is challenging. Here we present a compilation of ³⁶Cl denudation rates from alluvial samples in the Mediterranean and combine these with chemical weathering rates derived from water chemistry and satellite-dervied runoff data. We calculate mechanical erosion as the difference between the total denudation from cosmogenic ³⁶Cl measurements and the chemical weathering rates. Our results show a dominance of mechanical erosion in Mediterranean carbonate regions. We observe a strong scaling between mechanical erosion, catchment steepness and total denudation rate, but a weak scaling with chemical weathering. This implies that slope dependent erosion gets progressively more important with increasing denudation rates and therefore is linked to tectonic uplift.

Significant amounts of chemical weathering can bias cosmogenic denudation rate measurements. Therefore, we investigate this potential bias for the calculation of ³⁶Cl denudation rates in the reported Meditteranean sites, but find a limited influence.

These findings support a conceptual model of a dissolution speed limit in carbonates due to available water and acid such that areas of high local uplift require substantial mechanical erosion to balance uplift and form steep slopes. In contrast, areas experiencing low uplift rates with sufficient water availability (e.g. humid climate) can balance uplift entirely with dissolution resulting in subdued carbonate landscapes. This feedback explains why Meditterranean carbonate mountains are often high and steep compared to oher rock units, whereas carbonates in humid temperate climates form the subdued parts of the landscape.

The supply of fresh minerals to Earth’s surface by erosion is thought to modulate global climate by removing atmospheric carbon dioxide (CO₂) through silicate weathering. In turn, weathering of accessory carbonate and sulfide minerals is a geologically-relevant CO₂ source, which may dampen or reverse the effect of silicate weathering on climate. Although these weathering pathways commonly operate side by side, we lack quantitative constraints on their co-evolution across erosion-rate gradients. Using stream-water chemistry across a 3 order-of-magnitude erosion-rate gradient in shales and sandstones of southern Taiwan, here, we demonstrate that silicate, sulfide, and carbonate weathering are linked: Increasing sulfide oxidation generates sulfuric acid and boosts carbonate solubility whereas silicate weathering kinetics remain constant or even decline, perhaps due to buffering of the pH by carbonates. On timescales shorter than marine sulfide compensation, CO₂ emission rates from weathering in rapidly-eroding terrain are more than twice the CO₂ sequestration rates in slow-eroding terrain. On longer timescales, CO₂ emissions are compensated, but CO₂ sequestration rates do not increase with erosion, in contrast to assumptions in carbon cycle models. We posit that these patterns are broadly applicable to many Cenozoic mountain ranges that expose dominantly siliciclastic metasediments.

Topography in fold-thrust belts over geologic time reflects the development of an orogenic Coulomb wedge that represents a balance of tectonic and erosional forcings. The establishment of critically tapered topography is generally viewed under two contrasting mechanical frameworks: (i) shortening and rock uplift are occurring everywhere suggesting an orogenic wedge under mechanical failure everywhere; and (ii) rock displacement takes place along discrete fault planes, including the translation of uplifted topography laterally. Here we investigate whether the topography in central Nepal is maintained by a combination of rock uplift during sequential fault activity, the lateral translation of topography over ramp-flat subsurface geometries, and alternating phases of hinterland incision during out-of-sequence faulting and deformation front activity; if this is the case, then erosional efficacy dynamically varies along the orogenic wedge, in contrast to a wedge under mechanical failure everywhere. We test this hypothesis by employing a structural-kinematic model of the Neogene fold-thrust belt evolution of central Nepal and integrate this into a surface processes model applying end-member climatic scenarios, i.e., uniform precipitation and climatic change over geologic time. Model output is validated by comparing predicted geomorphic metrics with observed ones. Our results indicate a dynamic variability of erosional efficacy that promotes the interplay of two modes of orogenic wedge behaviour: phases of lateral translation of uplifted topography and in-sequence propagation of deformation fronts, and phases of hinterland incision during out-of-sequence fault activity.

The shape preferred orientation and connectivity of pores in reservoir rocks largely controls fluid migration properties, for example, by defining preferred flow directions. An accurate determination of preferred flow directions, observed as permeability anisotropy, is an integral part of reservoir characterization, due to profound effects on fluid migration. Numerous research fields, including groundwater studies, hydrocarbon exploitation, contamination mitigation, and CO2 sequestration, therefore seek methods to reliably characterize pore fabrics and permeability anisotropy. Many traditional methods face trade-offs between sample size and resolution, and measurements of permeability anisotropy require several oriented cores, where anisotropy may be masked by core-scale heterogeneity, and assumptions on the fabric orientation need to be made when less than six cores are measured. The magnetic pore fabric method has the potential to overcome these difficulties, and has shown promising empirical relationships to both the preferred orientation of pores, and permeability anisotropy. Magnetic pore fabrics are determined by impregnating rock with ferrofluid, and then measuring the anisotropy of magnetic susceptibility. These measurements provide a full 3D average fabric measure from a single core. So far, interpretation was compromised by large variability in the empirical relationships published in different studies. Here, experimental developments, and a conceptual and numerical model are presented that enable more thorough and quantitative interpretation of magnetic pore fabrics.

The pore space in siliciclastic rocks is one of the most important petrophysical properties in reservoir rock characterization. Of particular interest is the 3D distribution of pore space and permeability for the purpose of reservoir model development. We used a magnetic technique to determine the preferred orientation of the pore space. The approach is based on the injection of a magnetic ferrofluid, which is a stable colloidal suspension of approx. 10 nm-sized magnetite particles, into a rock specimen. The anisotropy of magnetic ferrofluid susceptibility (AMFFS) is then measured for its AMS and the orientation was compared with the rock’s AMS.

We used red Permo-Triassic sandstones of different Buntsandstein and Rotliegend facies, which represent Europe’s highest geothermal water and hydrocarbon reservoir potential. The used porosity methods were helium pycnometry, mercury injection porosimetry, computer tomography and ferrofluid injection. Although the used methods show a strong deviation for single samples, which is related to the different pore size ranges for which each method provide reliable information, the trends are comparable. The computer tomography showed pore space network to be parallel with the bedding of the sandstone. The AMFFS is also mostly similar to the rock’s AMS with principal minimum susceptibility axis normal to the bedding. However, small deviations of AMS and AMFFS axis orientation occur. This deviation could indicate that the ferrofluid fabric is related to a special size of pores. Further investigations are needed to verify this hypothesis.

Pyrolysis experiments and calculated thermostability diagrams show that iron bearing minerals (< 60nm) can be produced inorganically during oil formation in the ‘oil-kitchen’ or be precipitated in the reservoir via alteration or replacement of existing minerals. Here we use this observation to find a magnetic proxy that can be used to identify hydrocarbon fluid contacts by determining the morphology, abundance, mineralogy and size of the magnetic minerals present in reservoirs. We address this by examining core samples from the Tay Sandstone Member in the Western Central Graben in the North Sea.

The magnetic properties of core samples from the study area were determined using room-temperature measurements on a Vibrating Sample Magnetometer (VSM), low-temperature (0-300K) measurements on aMagnetic Property Measurement System (MPMS) and high-temperature (300-973K) measurements on a Kappabridge susceptibility meter while hydrocarbon fluid contacts were determined using wireline logs.

We observed magnetic enhancements at both gas-oil and oil-water contacts that are detectable both through magnetic susceptibility measurements and magnetic hysteresis measurements. This magnetic enhancement is due to the precipitation of new nanometric iron oxide (magnetite) and iron sulphide (greigite) phases. The magnetic enhancement may be caused by diagenetic changes or preferential biodegradation at the top of the oil column during early filling and at the oil water contact.

Minerals magnetics has been proposed as a means of improving our understanding of petroleum systems. We have carried out extensive rock magnetic experiments on core samples from the Tertiary reservoir sands of the Bittern and Pict Field, UK Central North Sea. This together with Petroleum Systems Modelling/Analysis has revealed the potential to characterise hydrocarbon migration pathway and fill-pattern through siderite identification. We have also suggested a plausible mechanism responsible for these observations. Furthermore, the presence of different flow zones or ‘compartments’ in petroleum reservoirs may also be identified through the distribution of magnetic minerals. In terms of ease of application in oil exploration and reservoir characterization, there is a potential to define this parameter very efficiently through the measurement of magnetic susceptibility.

Rocks are often subjected to dynamic stress that occurs during earthquakes, volcanic activity as well as human-induced activities. The aim of this study is to test if mechanical fatigue in rocks can be monitored by magnetic methods. For this purpose, the effect of cyclic-mechanical loading (150 + 30 MPa) on the magnetic susceptibility and its anisotropy of a magnetite-bearing ore with varying temperatures and environment was investigated. Our study shows that magnetic susceptibility decreases significantly (up to 23%) under air conditions and even in vacuum (up to 4 %) within the first ca. 1000 cycles. Further loading does not significantly affect the magnetic susceptibility which then remains more or less constant. However, a stronger decrease of susceptibility parameters is observed at higher temperatures. As magnetic susceptibility was measured after decompression of the loaded sample at room temperature, magnetostriction cannot be the reason for these changes. After cyclic loadings in air, the transformation of magnetite to hematite is the major mechanism affecting bulk magnetic susceptibility. The weak changes in magnetic susceptibility after vacuum loadings are related to the formation of damage and deformation structures observed on the surface of magnetite grains. We have shown that cyclic loading can change significantly the induced magnetization of a rock due to mineral transformation below < 1000 cycles and that mechanical fatigue, which is a precursor of the failure of a rock, is closely associated with these transformations. Therefore time-dependent magnetic susceptibility measurements can be used as a proxy parameter of mechanical fatigue.

Radiogenic strontium isotopes (⁸⁷Sr/⁸⁶Sr) of vein carbonates play a crucial role in the tectono-metamorphic study of fold-and-thrust belts and accretionary wedges and have been used to document fluid sources and fluxes, for example, along major fault zones. Moreover, the ⁸⁷Sr/⁸⁶Sr ratios of vein carbonates can trace the diagenetic to metamorphic evolution of pore fluids entrapped in accreted sediments. Here we present ⁸⁷Sr/⁸⁶Sr ratios of vein carbonates from the paleo-accretionary complex of the central European Alps (Glarus Alps, Switzerland) that formed during early stages of continental collision. We show that the vein carbonates trace the Sr isotopic evolution of pore fluids from an initial seawater-like signature towards the isotopic composition of the host rock. This relation allows us to constrain the diagenetic to low-grade metamorphic conditions of deformation events, including imbricate thrusting, folding, cleavage development, stratal disruption and tectonic transport of thrust slices, bedding-parallel shearing, and extensional vein-formation. Taken together, the strontium isotope systematics of vein carbonate provides new insights into the prograde to early retrograde tectonic evolution of Alpine accretionary complex and helps to understand aspects that are not sufficiently clear from traditional cross-cutting relationships.

The reaction of serpentinized peridotites with CO₂-bearing fluids to listvenite (quartz-carbonate rocks) requires massive fluid flux and maintained permeability despite volume increase. Here we investigate listvenites and serpentinites samples from Hole BT1B of the Oman Drilling Project to improve our understanding of the mechanisms and feedbacks of fracturing and vein formation during peridotite carbonation. The samples are characterized by a high abundance of magnesite veins which are often bundled into closely-spaced, parallel sets. Relative cross-cutting relationships suggest that these veins are among the earliest structures related to carbonation of serpentinite. These veins often show some features that are typical for antitaxial veins such as growth from a median line outwards. Their bisymmetric chemical zonation of variable Ca and Fe contents, a systematic distribution of SiO₂ and Fe-oxide inclusions in these zones, and cross-cutting relations with Fe-oxides and Cr-spinel suggest that they are micro-scale reaction fronts recording the replacement of serpentine by carbonate. Local dolomite precipitation and voids along the vein – wall rock interface suggest that the veins acted as a preferred fluid pathway also after the first fracturing formed the central parts of the zoned magnesite veins. The close spacing and (sub)parallel alignment of the veins points to preferential fracturing of the weaker wall rock, in line with the interpretation that the veins formed in a serpentine matrix. The zoned magnesite veins therefore record an early stage of fluid infiltration during listvenite formation, at which focused fluid flow was controlled to large parts by external tectonic stress.

The analysis of Coulomb stress changes has become an important tool for seismic hazard evaluation because such stress changes may trigger or delay next earthquakes. Processes that can cause significant Coulomb stress changes include coseismic slip, earthquake-induced poroelastic effects and transient postseismic processes such as viscoelastic relaxation. In this study, we use 2D finite-element models for intracontinental normal and thrust faults to investigate the spatial and temporal evolution and the interaction of pore fluid pressure changes and postseismic viscoelastic relaxation. In different experiments, we vary (1) the permeability of the upper or lower crust and (2) the viscosity of the lower crust or lithospheric mantle, while keeping the other parameters constant. The results show that the highest pore pressure changes occur within a distance of ~ 1 km around the lower fault tip. In the postseismic phase, the pore pressure relaxes depending on the permeability in the upper crust until the pore pressure reaches the initial pressure of the preseismic phase. For high permeabilities in the upper crust, postseismic velocities within a few kilometers around the fault reach around 120 mm/a and decrease rapidly with time, whereas for low permeabilities velocities remain lower over the years after the earthquake. Models with low viscosity of the lower crust show that postseismic viscoelastic relaxation and poroelastic effects overlap in the early postseismic phase and decrease gradually within a few years after the earthquake. Higher viscosities lead to lower velocities, that last for decades on scales of several tens of kilometers.

Information about the recent stress state of the upper crust is important for understanding tectonic processes and for the use of the underground in general. A currently important topic, the search for a radioactive waste deposit, illustrates this relevance, as the crustal stress state is decisive for the short and long-term safety of a possible repository. For example, the integrity of the host rock due to the activation or reactivation of faults and associated fluid pathways during.

However, the level of knowledge of the upper crustal stress field in Germany is quite low. The World Stress Map (WSM) and a new stress magnitude database give some insights, but only spatially unevenly distributed, often incomplete and rarely of good quality. Therefore, we present the first 3D geomechanical model of Germany that allows a comprehensive prediction of the complete stress tensor. The model covers an area of 1250 x 1000 km² and contains 20 units with individual rock properties (Young's modulus, Poisson's ratio and density). It is calibrated against the datasets of the WSM and the magnitude database. Our results are in good agreement with the orientation of the maximum horizontal stress and show a good fit regarding the magnitudes of the minimum and maximum horizontal stress.

The Zagros Mountain Front Flexure (MFF) makes a prominent topographic and structural step along the Zagros Fold-Thrust Belt that accommodates a significant amount of shortening between the Eurasian and Arabian plates. Here, the structural style below the MFF in the Kurdistan Region of Iraq was reconstructed using balanced cross-sections and forward modeling, and Late Pleistocene-Holocene fault-slip rates were calculated across several structures using luminescence dating of river terraces along the Greater Zab River. A balanced and retro-deformable cross-section for the NW Zagros reveals that reverse displacement on a basement fault underlying the MFF, along with fault-related folding above the Triassic detachment, is indispensable to explain the observed structural relief. The uplift rates of river terraces, obtained from their elevation and ages, indicate ongoing slip on faults when integrated with the kinematics of fault-related folds for the structures. The basement fault underlying the MFF accommodates 1.46±0.60 mm a^-1 of slip, while a more external basement fault further to the SW is accommodating less than 0.41±0.16 mm a^-1. Horizontal slip rates from detachment folding above the Triassic detachment in two anticlines (Sarta and Safin) within the Zagros Foothills are 0.40±0.10 and 1.24±0.36 mm a^-1, respectively. Balanced cross-section, distribution of river terraces, and regional topography indicate that basement thrusting, and ductile thickening of the crust are restricted to the NE parts of the belt, and the deformation is limited mainly to folding and thrusting of the sedimentary cover above a Triassic basal detachment there in the SW parts.

Tectonic faults are of great importance for many underground applications such as hydrocarbon extraction, geothermal operations or nuclear waste repositories. In particular, the fault reactivation potential is crucial in regards of safety and efficiency of these applications. Major influences on the reactivation potential are the contemporary tectonic stress field and changes to it due to anthropogenic activities. One measure of the reactivation potential of faults is the ratio of resolved shear stresses to normal stresses on the fault surface, the slip tendency. The components of the stress tensor required for slip tendency analysis have been provided by the 3D geomechanical numerical model of Germany and its adjacent regions of the SpannEnD project. The derived stresses are mapped onto selected faults in order to calculate their slip tendency.

As only a finite number of 3D fault geometries could be generated, criteria for the selection of faults relevant to the scope of the SpannEnD project were identified. Their application led to the selection of 60 faults in the model area. For the selected faults simplified geometries were created (fault set 1). For a subset of the selected faults, vertical profiles and seismic sections could be used to generate semi-realistic 3D fault geometries (fault set 2). Slip tendency calculations using the stress tensor from the SpannEnD model were performed for both 3D fault sets and allow for an assessment of the fault reactivation potential which can be compared with the distribution of seismicity.

Luminescence is the non-incandescent emission of light from materials excited by an electron beam. Electron irradiation raises sample electrons to an excited state, which then emit a photon as they return to a lower energy. Luminescence phenemona may be studied in several ways, including spectral and spatial methods. Whilst cathodolominescence (CL) has become an established method of analysis for Earth materials, other forms of luminescence in minerals should not be overlooked. Photoluminescence (PL) studies, for example, allow for emission and excitation spectroscopy to be examined in weak- to strongly luminescent minerals, such as wilmenite. In the case of quartz PL, emission spectroscopy investigations have shown that excitation at different wavelengths produces highly variable emission spectra that relate to one or more transitions for excitation. As the building blocks to rocks, minerals and the atoms or ions within preserve critical information concerning the conditions attending growth or subsequent evolution - thus, investigation of these can inform on the origin or surface/near surface interactions relating to environmental change. As a non-destructive technique used in the study of rare materials (e.g., Lunar meteorites) luminescence imaging and spectroscopy have the potential to help characterise, as well as, elucidate domains or reveal fine-scale features not resolvable by optical methods. Advances in instrumentation now permit the collection of multi-dimensional data sets (e.g., hyperspectral) that can be interrogated off-line. The simultaneous capture and interpretation of compositional and luminescence signals has the potential to greatly improve our understanding of causes of luminescence, be these trace activator or defect.

Zircon Raman dating is a debated concept in thermochronology. It is based on the disruption of the zircon lattice by α-disintegration of ²³⁸U, ²³⁵U, ²³²Th, and their daughter nuclides. This radiation damage leads to broadening of the Raman bands. A date is calculated from the measured Raman bandwidths, and the effective Uranium (eU) content, measured in the same spot. Radiation damage anneals at elevated temperatures; thus the Raman date is interpreted with regard to its closure temperature (T_c) as an event, cooling or mixed age, depending on the thermal history of the sample. We present zircon Raman ages calculated from the widths of the 439, 1008, and 356 cm^-1 Raman bands for samples with different thermal histories. We discuss: (1) criteria for evaluating the Raman data by inter-band comparison; (2) the effect of partial annealing on the dating results; (3) the spatial matching of Raman and eU microanalysis.

Raman spectroscopy is becoming an increasingly important investigative tool in modern geosciences. So it has been applied in the examination of a variety of materials, including meteoritic and igneous rocks, as well as natural and synthetic minerals and crystals.

This is not least due to the many advantages of Raman spectroscopy, like very fast measurements, small spot size or different samples consistency.

One main investigation area are meteorites, because new space mission programs to Moon and Mars are underway. In these new missions, robots are equipped with analytical instruments to probe the chemistry and constitution of the materials on the surface of the respective bodies. One of the promising mobile techniques is Raman spectroscopy. Therefore, the experience and measurement of comparable samples like meteorites, basalts or ophiolitic material helps us a lot. Several types of different meteorites have already been investigated here, for example, those recovered from the Neuschwanstein, Almahatta Sitta, Braunschweig or Tscheljabinsk fall. Furthermore, we started to investigate Meteorites from the Moon and Mars.

Raman methods can also help to study mineral compositions, because the spectra can aid in the classification, based upon crystal structure and mineral composition. In combination with electron microprobe, it is a perfect tool to characterize different polytypes and polymorphs. As such, it has been possible to distinguish between graphite, graphene and diamond within some of our meteorite samples, and between coesite, stishovite and other quartz polymorphs, present. These critical data provide pressure and temperature information for the meteorite and its parent body.

Effect of Co substitution in pyrite was investigated using a Raman microprobe. Textural appearance of Co-bearing pyrite was visualized by mapping method. The revealed Raman map tightly correlates with a Co distribution map obtained by electron microprobe and µ-energy-dispersive X-ray fluorescence microscope. In addition, a strong influence on the pyrite spectra due to sample preparation was documented. The standard mechanical polishing caused highly broadened modes at upshifted frequencies, which could be avoided by analyzing of sample polished with Ar broad ion beam or non-polished cut sample. However, the effect of Co on pyrite spectra is independent of the sample preparation. Additionally, the Raman method has several advantages over other methods. For instance, It does not require sample preparation, vacuum chamber and wavelength-dispersive system and operates with a laser instead of X-ray. Thus, the Raman method can be used as a possible tool for differentiation of Co-bearing pyrite from pure one.

Three lacquer peel profiles were prepared from a copper tailings deposit in Central Chile. The peels were taken from two sides at varying depths of the tailings heap. Parallel to that, samples were taken from each layer within the peels for bulk XRF analysis and particle size analysis. The peels were analysed by Hyperspectral Imaging (HSI, VNIR- SWIR, 400 – 2500 nm wavelength) with the Specim SisuRock system and µXRF mapping using M4 Tornado Plus from Bruker for chemical comparison.

The lacquer peel method worked well for sandy tailings with the polyvinyl alcohol Mowiol as glue with a peel size of 50 x 30 cm. All peels were stable, transportable and ready to be measured by HSI after about one day of drying.

The HSI data shows that reflectance of the different material layers within the peels is correlated with particle size data from sieving (Camsizer, Retsch and Sedigraph, Micromeritics). This is important information for a possible reprocessing of copper sulfides, since tailings deposition works as a particle sorting process and, flotation efficiency depends on particle size. Furthermore, endmember classes were extracted from the HSI data using the Pixel Purity Index on lacquer profile 2, which were used to classify the remaining profiles. The HSI classification was registered to the µXRF mappings and the HSI classes were attributed the copper concentration from µXRF. With this information, zones of copper enrichment could be localized using the HSI data in combination with µXRF. This process is also applicable on tailings drill cores.

The “Green Future”; a concept of desirable European climate-neutral living conditions, which is the goal of the EU Green Deal means a huge increase in the use of mineral raw materials. Minerals are an essential component for many of today’s rapidly growing clean energy technologies – from wind turbines and electricity networks to electric vehicles. But ensuring that these and other key technologies can continue to rely on sufficient mineral supplies to support the acceleration of clean energy transitions is a significant and often-ignored challenge.

As an example, the frequency of new discoveries has fallen even with a significant increase in exploration budgets. Between 2007 and 2016, ~54B€ were spent for a return of 25B€ of gold - an unsustainable exercise! Therefore, a new way of approaching mineral exploration must be adopted and traditional methods of exploring for greenfield mineral deposits need to be rethought to cushion this trend.

The need to bring these deposits faster on-line in the value chains of the circular economy, and the transformation into green technology items, needs modern and updated tools. Data integration and geographic information system (GIS) based analyses, which can improve exploration and detection of mineral deposits in Europe and elsewhere, are among those tools. However, the use of new exploration techniques needs to be allied with new geological, geochemical, geophysical, and drilling data and, most importantly, access to the territory to evidence Europe’s new mineral potential.

Investigating rare metal potentials of the Alpine regions is of great importance to progress towards future supply independence. Sphalerite is an important carrier of Co, In, Ga, Ge, and Sb, and we know from the Eastern Alps, that vein deposits roughly host 66% of the Co, 18% of the Ga and 4% of the In resource. Here, we present data of sphalerite (and chalcopyrite) from two contrasting vein deposits in the Southern Alpine basement: the Pfunderer Berg (PF) Cu-Zn-Pb-Ag mine near Klausen and the Rabenstein (RS) F-Zn mine in the Sarn Valley. The PF mine is a Permian intrusion-hosted vein deposit with a chalcopyrite-sphalerite-galena-sulphosalt paragenesis. RS mine is a vein deposit with fluorite-sphalerite paragenesis, probably related to the Periadriatic fault.

The two ores show contrasting textures and chemistry of sphalerite, which are primarily related to formation temperature: at PB high-T ZnS is black and homogeneous and enriched in Fe-Mn-Cd-Cu-Se-Co-In-Sn, while at RS low-T ZnS is honey-coloured and zones and enriched in Pb-As-Ag-Sb-Hg-Tl-Ga-Ge. Rare metal medians at PB are 303, 124, and 187 µg/g for Co, In, and Sn. At RS medians for Ga, Sb, Ag, Ge, are 383, 203, 85, and 9.1 µg/g. Spot analyses can reach higher values, either related to mineral inclusions (PB) or to zoning (RS). Across zoned ZnS grains, co-variations with Fe-content (0.3 to 6 wt.%) or Cu (70 to 5000 µg/g) are related to evolving hydrothermal pulse. Results demonstrate significant rare metal variations across deposit types, but also complexities of fractionation within given deposits.

A more sustainable society with CO₂ neutral energy production requires substantial amounts of trace metal(loids). However, our understanding about the fractionation processes of these elements between the epithermal and porphyry environment is still limited, but may be essential to secure the future supply of these rare commodities. The porphyry-epithermal mineralization on Limnos (Fakos, Sardes, Kaspakas) show variable Te and related element (e.g., Au, Ag) contents, and therefore represent a natural laboratory to define key fractionation and enrichment processes.

Subalkaline to alkaline igneous rocks and siliciclastic sediments host the porphyry-epithermal mineralization on Limnos. Pyrite, magnetite and minor chalcopyrite dominate the porphyry mineralization, whereas the epithermal stage comprises pyrite, sphalerite, galena, chalcopyrite together with minor sulfosalts (e.g. enargite, tetrahedrite-tennantite, bournonite), tellurides and native Au. Pyrite is ubiquitous in most alteration-types and its chemical composition, therefore provides insights into mineralization processes at variable fluid conditions. Epithermal pyrite is enriched in most trace elements (e.g., As, Ag, Sb, Au, Pb, Tl) compared to porphyry pyrite (Se-bearing), most likely caused by a more favorable mineralization process in the epithermal environment. However, Te shows no systematic variation between porphyry and epithermal pyrite, which we refer to its competitive incorporation between pyrite, galena, sulfosalts and tellurides in the epithermal stage. Sulfur isotope variations in pyrite report on the contribution of magmatic and meteoric fluids in variable proportion between different mineralizations on Limnos. We present a hydrothermal model based on the mineralogical and chemical data, defining key fractionation processes for Te and related elements in the porphyry-epithermal environment.

European geology ranges from old mountain chains with more or less altered magmatic and sedimentary deposits over glaciogenic materials from the recent Ice Ages to very young marine or alluvial deposits etc. Thus, the ground under our feet carries a large variety of raw materials from sand and gravel over granites and marbles to precious or critical metals and minerals. Humans have extracted these materials from the (sub)surface since prehistorical eras, and these indispensable substances have and still do to a very large extent contribute to the evolution of humankind, and through the last couple of decades, national or regional geological surveys have played an important role in mapping these resources.

Most geological surveys host data on raw materials, however, data are typically organized in different ways from one country to another based on different geological traditions, legal frameworks etc. The MINTELL4EU project builds on previous projects to collect a selection of these national/regional raw material data, to store these in a central database, and finally to offer a visualization in a harmonized way at the European Geological Data Infrastructure (EGDI). This central database called MIN4EU includes, among other assets, the location of individual mineral occurrences and mines, aggregated statistical data at national level on production, trade, resources and reserves compiled in the electronic Minerals Yearbook, as well as data on test cases on UNFC. A brief overview of the database content and the resulting visualization through EGDI will be provided.

The MINTELL4EU project builds upon previous European-wide mineral intelligence projects, including ORAMA, MICA, MINventory and particularly the Minerals Intelligence Network for Europe project (Minerals4EU). In this most recent iteration, we have surveyed European geological surveys and other relevant data sources for detailed information on European mineral production, trade, resource, reserve and exploration data.

We present an updated electronic Minerals Yearbook, a snapshot of current European mineral intelligence. We will illustrate some preliminary data analysis of resources and reserves using baseline data from the previous survey in 2013. Time series analysis of production and trade data from 2013 will also be shown. We also present comparisons of European mineral data with global datasets for selected commodities essential to the net-zero carbon transition.

The evolution of Earth’s climate over geological timescales is linked to surface erosion by weathering of silicate minerals and burial of organic carbon. However, methodological difficulties in reconstructing erosion rates through time and feedbacks among tectonics, climate, and erosion spurred an ongoing debate on mountain erosion sensitivity to tectonic and climate forcing. A key question is whether late Cenozoic climate cooling has increased global erosion rates or not. The Himalaya plays a prominent role in this debate as its erosion produces a large fraction of global sediments delivered to ocean basins. We report a 6-Myr-long record of cosmogenic ¹⁰Be-derived erosion rates from the north-western Himalaya, which indicates that erosion rates in this region varied quasi-cyclically with a period of ~1 Myr and increased gradually towards the present. We hypothesize that the observed pattern of erosion rates occurred in response to the tectonic growth of the Himalaya by punctuated basal and frontal accretion of rocks from the underthrusting Indian plate and concomitant changes in topography. In this model, basal accretion episodically changes rock-uplift patterns, which brings landscapes out of equilibrium and results in quasi-cyclic variations in erosion rates. We used numerical landscape evolution simulations to demonstrate that this hypothesis is physically plausible. In addition, we suggest that the long-term increase in erosion rates was likely driven by successive basal accretion and the commensurate topographic growth in the interior of the Himalayan thrust wedge. Because tectonic accretion processes are inherent to collisional orogenesis, they likely confound climatic interpretations of erosion rate histories.

Cosmogenic nuclide analysis in sediment from the Earth’s largest rivers yields mean denudation rates of the sediment-producing areas that average out local variations commonly found in small rivers. Using this approach, we measured in situ cosmogenic ²⁶Al and ¹⁰Be in sand of >50 large rivers over a range of climatic and tectonic regimes covering 32% of the Earth’s terrestrial surface.

In 35% of the analyzed rivers, ²⁶Al/¹⁰Be ratios are significantly lower than these nuclides´ surface-production-rate ratio of 6.75. We explain these low ratio by a combination of slow erosion and shielding in the source area, and we provide estimates of the buffering timescales of sediment transport using paired nuclides. In the other 65% of studied rivers, ²⁶Al/¹⁰Be ratios are within uncertainty of their surface production-rate ratio, indicating cosmogenic steady state. For these rivers, we obtain a global source area denudation rate of 141 t/km²´yr (3.07 Gt/yr). By assuming that this sub-dataset is representative of the global land surface, we upscale to the total surface area for exorheic basins, thereby obtaining a global, millennial-scale denudation flux of 15.2 ± 2.8 Gt/yr. This value is slightly lower than published values from cosmogenic nuclides from small river basins (23 (+53/-16)) Gt/yr) upscaled using a global slope model, and also lower than modern sediment and dissolved loads exported to the oceans (24.0 Gt/yr). Our new approach confirms an estimate of global dissolved and solid matter transfer that converges to an encouragingly narrow range of within 35%.

Climate warming and the related permafrost degradation are thought to influence slope stability, landscape evolution, and the natural hazard potential in polar- and high mountain regions. In this context, we investigate the coastal range of Forkastningsfjellet, Svalbard, which is affected by rock slope deformations of different magnitudes and age. Based on a detailed multidisciplinary investigation, we discuss the causes, kinematics and timing of rock slide activity.

The distinct stair-stepped morphostructural relief of the Forkastningsfjellet ridge is the result of a giant postglacial deep-seated rock slide, which involved a minimum rock mass volume of 0.10 km³ and was probably related to the deglaciation of Isfjorden. Rock failure and movement in the hanging wall of a NW-dipping listric sliding surface led to the fragmentation of the sliding mass into separated tilt blocks.

Since then mass wasting and seacliff erosion take place along the steep slopes of the coastal tilt blocks and on August 16^th 2016 a coastal block of the postglacial Forkastningsfjellet rock slide was affected by a rotational rock slide comprising a volume of 175,000m³. As the reactivation of individual slide blocks could have severe consequences for the coastal regions of Longyearbyen by related displacement waves, a back analysis was carried out to derive potential controlling and triggering factors of the recent slope failure. Although the analysis suggests a structural control on the type and mechanism of slope failure, a significant impact of climate-related factors like permafrost degradation and increasing availability of water has to be considered.

Relict permafrost features (RPF) indicated by specific patterns of soil, sedimentary and landform structure are characteristic of Central Russian Plain watersheds. Paleocryogenic polygonal networks appear in a pattern of semi-regular spots, blocks and polygons on the surface usually associated with pseudomorphs of ice wedges or sand casts in correlated deposits. This research aimed at distinguishing RPF in sedimentary structure and its correlation with the modern and paleolandscape structure of 3 ha watershed area exposed in constantly expanding trenches. Interpretation of multi-temporal UAV-photography, lithological investigation of 21 sections and apparent magnetic susceptibility measurements allowed to reconstruct spatial organization of the postglacial sedimentary sequence of the key site. Eight sedimentary beds were distinguish starting with Late Saalian limnoglacial base followed by lacustrine (pond-like) facies of the Pleniglacial and solifluction-colluvial lenses of the Late Pleniglacial and Late Glacial up to Holocene colluvial and agrogenic slope facies. At least three generations of inherited wedge-like deformations have been revealed in these stratified thicknesses preliminary attributed to the onset of the last glaciation and its maximum and to one of the Late Glacial coolings. It is established that established are contrastingly displayed in the sedimentary structure, paleolandscapes and modern soil and vegetative cover, however, are rarely or almost not shown in the actual microtopography. Established relationship of ice wedge pseudomorphs and shallow dry gullies allowed interpreting the origin of the latter as initially cryogenic dells infilled by colluvial, incl. agrogenic, deposits and partially incised by agrogenically instigated slope erosion of the last century.

Speleothems (secondary calcium carbonate formations) offer significant potential for recording environmental processes above caves, an area increasingly referred to as the Critical Zone. Speleothems grow for hundreds to millions of years, with absolute chronology from U-Th and U-Pb chronometers. The solution properties of rainwater infiltrating the soil and underlying caves respond to environmental controls. These environmental signals can be preserved within speleothem carbonates. Recent efforts to calibrate, model and interpret this complex geochemistry has progressed along multiple paths. Here we bring together recent examples, including: i) calibrating and using Li isotopes for reconstructing weathering intensity [1,2]; ii) the use of Ca isotopes for reconstructing changes in rainfall amount [3]; iii) the combined use of d¹³C, ¹⁴C and d⁴⁴Ca to demonstrate changes in soil respiration [4]. Combining these proxies provides the potential of regional-scale input into climate, weathering and the chemical cycling of elements, on timescales from thousands to millions of years.

[1] C.C. Day et al. Lithium isotopes and partition coefficients in inorganic carbonates: proxy calibration for weathering reconstruction. GCA. [2] P.A.E. Pogge von Strandmann et al. 2017. Lithium isotopes in speleothems: Temperature-controlled variation in silicate weathering during glacial cycles. EPSL. 469, 64–74. [3] R.A. Owen et al. 2016. Calcium isotopes in caves as a proxy for aridity: Modern calibration and application to the 8.2 kyr event. EPSL, 443, 129–138. [4] F.A. Lechleitner et al. (in review). Stalagmite carbon isotopes suggest deglacial increase in soil respiration in Western Europe driven by temperature change. Climate of the Past.

Weathering is the fundamental precondition for erosion and soil formation which sculpture Earth´s surface. It is a complex interplay of minerals, rock fabric, tectonical fractures, climate, and organic activity.

To explore the dependences between these factors two weathering profiles on magmatic bedrock were compared using six-meter-deep soil pits and drill cores in both a humid and a Mediterranean climate regime of Chile. Detailed mineralogical and geochemical investigations of soil and saprolite were combined with spatially highly resolved geochemical analyses of fracture-related rock weathering.

The maximum saprolite depth in the humid climate turned out to be much shallower (approx. 6 m) than in the Mediterranean climate (almost 30 m). However, the entire soil-pit profile in the humid climate is characterized by distinct chemical depletion and intense mineral weathering (predominantly chemical weathering), whereas the Mediterranean profile only shows weak chemical and mineral weathering but high degrees of fracturing (predominantly physical weathering). This study suggests that surface inputs (water, O₂) initially enter the subsurface via tectonical fractures and trigger reactions such as iron-oxidation in Fe(II)-bearing silicates which induces fracturing or the transformation of feldspars which can hamper the weathering advance by porosity reduction. The higher content of Fe(II)-bearing silicates in the bedrock of the Mediterranean climate is thus considered the critical factor for the different developments of the two profiles.

This study stresses the magnitude of control the mineralogical composition has on weathering processes and that surface processes like erosion cannot be fully understood without a thorough investigation of the subsurface.

The ecology and structure of many tropical coral reefs have altered markedly over the past few decades. Drivers of this degradation range from direct local damage from destructive human practices to global scale climate stressors, and especially those associated with elevated sea‐surface temperature anomalies. A major consequence of these climatic and pervasive local stressors has often been a rapid decrease in the abundance of habitat building corals, which has consequently reduced reef structural complexity and coral carbonate production rates. Equally, many reefs have been impacted by changes (both increases and decreases) in the abundance of bioeroding taxa such as parrotfish, urchins, sponges and microendolithic organisms. The collective effect has been to alter the rates and relative balance of carbonate producing and eroding processes on many reefs. Such changes are of increasing interest because these processes directly regulate net rates of reef carbonate production and sediment generation, and collectively can impact upon multiple geo‐ecological functions on reefs. These functions include reef‐building and the capacity of reefs to accrete vertically in response to sea‐level rise, and the supply of sands necessary to sustain beaches and reef islands. This talk will discuss recent progress in developing methodologies to estimate rates of reef carbonate production, reef growth and sediment generation. It will then use selected recent field examples to highlight changes in these processes in response to ecological disturbance, and highlight the potential to integrate these data into numerical and lab-based modelling approaches than be used to predict coastal wave exposure under future sea level rise scenarios.

The effects of changing climate and environmental conditions on coral reef islands have received a lot of attention, and the findings are discussed broadly. The low elevation of such islands above mean sea level and the largely unconsolidated sediment is exposing them to hydrodynamic processes. Coral reef islands are formed by sediment sourced from the surrounding reef systems and depend on these reef systems as continuous material suppliers. Shifts in these governing conditions may affect these landforms, however the results of such shifts remain controversial as island-response is likely to be regionally specific. The present sedimentological study addresses the formation of a reef island in the Spermonde Archipelago, Sulawesi, and its development through time. Sediment cores of 10 m length taken on the island allowed to reconstruct the sedimentary history of this mid-shelf island. The carbonate facies from these cores reflects the development of the island and thus allows for inferring the evolution of the surrounding ecosystem as well as the hydrodynamic regime that governed sedimentation. While sediment from the maximum depth of the cores mirror parautochthonous accumulation in a lagoonal environment, subsequent sedimentation is thought to be the result of hydrodynamic events with oscillating intensity.

Early-diagenetic cementation of tropical carbonates results from the combination of numerous physico-chemical and biological processes. In the marine phreatic environment it represents an essential mechanism for the development and stabilization of carbonate platforms. However, many early-diagenetic cements that developed in the marine phreatic environment are likely to become obliterated during later stages of meteoric or burial diagenesis. In this contribution, a petrographic microfacies analysis of Holocene Halimeda segments collected on a coral island in the Spermonde Archipelago, Indonesia, is presented. Through electron microscopical analyses of thin sections, this study shows that segments are characterized by intragranular cementation of fibrous aragonite, equant Mg calcite (3.9 – 7.2 Mol% Mg), bladed low Mg calcite (0.4 – 1.0 Mol%) and mini-micritic Mg calcite (crystal size < 0.1 µm; 3.2 – 3.3 Mol% Mg). The consecutive development of (1) fibrous aragonite, (2) equant Mg calcite and (3) bladed low Mg calcite is explained by shifts in pore water pH and alkalinity through fluid kinetics and microbial sulfate reduction. Microbial activity appears to be the main trigger for the precipitation of mini-micritic Mg calcite, as inferred from the presumable detection of an extracellular polymeric matrix. Radiocarbon analyses of five Halimeda segments furthermore indicate that intragranular aragonite and Mg calcite cementation of microstructurally complex carbonate constituents in the shallow marine phreatic environment is a slower process than intergranular ooid cementation, characterized by relatively smooth surfaces.

Microbial mediation is considered an important process for the formation of primary dolomite at ambient temperature. Yet, no structural, mineralogical, chemical or isotopic means exist to discern this mode of dolomite formation from secondary dolomite. To explore the utility of metal isotopes in allowing this distinction we characterize magnesium and calcium stable isotope ratios in primary (proto)dolomites from a modern hypersaline environment.

Samples from the Khor Al-Adaid sabkhas in Qatar show consistent isotopic differences of Ca isotopes (Δ^44/40Ca) of -1.1 and -1.8 ‰ between solution and (proto-)dolomite and -0.3 to -0.7 ‰ between solution and organic phases, consistent with a previously postulated two-step fractionation process that enriches microbially mediated dolomite in ⁴⁰Ca (Krause et al., 2012). Mg isotopes reveal a more complex picture with varying magnitudes of fractionation across different microbial zones in the shallow subsurface in agreement with a wide range of Δ^26/24Mg-values previously observed in the sabkahs of Abu Dhabi (Geske et al., 2015) and suggested impact of microbial activity on δ²⁶Mg (Riechelmann et al., 2020). The high variability is moreover modulated by authigenic palygorskite formation close to the water-sediment interface that yields consistently ²⁶Mg-enriched signatures.

While clay-free sites suggest simple Mg precipitation from seawater into dolomite (Shalev et al., 2020), our data shows that Mg uptake into clay minerals does not allow a straightforward identification of a characteristic isotopic fingerprint in ancient primary dolomite, but shows potential to obtain a detailed picture of specific microbial involvement.

Here, we present element to Ca ratios (Mg/Ca, Sr/Ca, Na/Ca and Mn/Ca) and stable isotope data (δ¹⁸O, δ¹³C) of the parasitic foraminifer Hyrrokkin sarcophaga, collected from two different host organisms, Desmophyllum pertusum - a cold-water coral commonly found in cold-water coral reefs and Acesta excavata - a bivalve associated with cold-water coral reefs.

Our results reveal that the geochemical signature in H. sarcophaga is influenced by the host organism. Sr/Ca ratios are 1.1 mmol mol^-1 higher in H. sarcophaga that infest D. pertusum, which could be an indication that dissolved host carbonate material is utilised in shell calcification. Similarly, we measured 3.1 ‰ lower δ¹³C and 0.3 ‰ lower δ¹⁸O values in H. sarcophaga that lived on D. pertusum, which might be caused by the direct uptake of the host’s carbonate material with a more negative isotopic composition. Moreover, we observe higher Mn/Ca ratios in foraminifera that lived on A. excavata but did not penetrate the host shell compared to specimen that did.

H. sarcophaga is therefore, unlikely to be a reliable indicator of paleoenvironmental conditions using Sr/Ca, Mn/Ca, δ¹⁸O or δ¹³C unless the host organism is known and its geochemical composition can be accounted for. Still, these results provide interesting insights in the calcification process of these specialized foraminifera.

A 3D web-service has been developed for the modeling and for the management of karst aquifers and related groundwater resources. Visual KARSYS allows users to build explicit models of karst aquifers via a 3D geological modeller (gmLib Python library) and a series of tools (i.e. algorithms) which provide characteristics of groundwater bodies by applying hydraulic principles.

Visual KARSYS is designed for geologists or hydrogeologists working for public institutions or private companies, but also for administration or decision makers facing various issues in karst environments: groundwater resources, natural hazards, geothermal energy, civil engineering, etc. Outputs from Visual KARSYS (data, models and resulting documentation) can be shared between users for being consulted or edited.

The web-service is available at visualkarsys.com and it is currently free-of-charge and we encourage users to use it. In March 2021, more than 425 users already registered and ~150 persons attended the training courses.

The Visual KARSYS project is supported by the Swiss Federal Office for Environment via the grant for the promotion of environmental technology (2016-2019, UTF 537.13.16).

Digital 3D geomodels are becoming a routine tool for geoscientific research, engineering and surveying. Most models incorporate various datasets into a simplified virtual representation of reality.
Turning the process of model building into something sustainable, so that future users can build on the results and insights provided by a given model raises a number of questions:

• How can we assure that other users can reconstruct the same model given the required information?
• How do we ensure that repetition of a construction using the same information yields the same geomodel, such that the process itself is reproducible?

With Geohub we present a theoretical framework to represent a construction process of a geomodel. We represent a construction process as directed acylic hypergraph. Each node of this hypergraph represents a dataset used or generated as part of the construction process.
Each hyperedge represents a construction step, that transforms a set of input datasets into a single possible intermediate output dataset. Construction steps consists of a generic representation, which is executable with a computer.
This enables us to repeat a construction process to:

• check if the construction of a geomodel is reproducible by comparing the results of different repetitions
• update a geomodel with new input data by repeating the construction using the new dataset
• generate different realisations of the same geomodel built by input dataset based on stochastic distributions.

Eventually we present an implementation of this framework ensuring repeatability of the construction process and reproducibility of the geomodels constructed in this way.

Although 3-D geological modeling has been mostly employed in the prospection and exploitation of ores, oil and gas, its importance in the field of groundwater resources management is considerably increasing. Traditional 3-D geological modeling schemes are based on explicit digitization of geological units and structures. Progresses in 3-D interpolation techniques have favored the emergence of implicit modeling, in which geological surfaces are automatically created from hard data and interpretation. The major benefit of implicit modeling relies on its speed. In this work the implicit modeling approach was applied to conceptualize and model a karst aquifer in southwest Germany, using digital elevation data, geological maps, borehole logs, and geological interpretation. Dip and strike measurements as well as soil-gas surveys of mantel-borne CO₂ were conducted to verify the existence of a postulated fault. The geological model was automatically translated into a numerical groundwater flow model that was calibrated to match measured hydraulic heads, spring discharge rates, and flow directions observed in tracer tests. Refinements of the numerical model’s spatial parametrization was iteratively conducted, using the geological model for visualization of interim simulations. As the results of numerical modeling may support or contradict the 3-D geological model, additional geological insights can be eventually gained in this way. The geological model allowed the proper assessment of the system geometry and the definition of boundary conditions. The numerical groundwater flow model was applied to evaluate the potential risks from limestone quarries to local water supply wells.

3D modelling of complex salt structures for the purpose of final disposal of radioactive waste requires a particulary high degree of precision. In this perspective, conventional geological 3D modelling software fails to produce satisfying results. For this reason, BGR uses the software openGEO that allows the integration of all types of basic geoscientific data. In particular, for the management of ground-penetrating radar measurements a group of specific tools has been developed as part of the software package.

However, compared to conventional 3D geological modelling software openGEO is more labour-intensive. This is because model surfaces are not created by an algorithmic procedure. Quite the contrary, surfaces need to be constructed manually by considering and incorporating all accessible data.

Especially for areas within the model where data are limited and/or geological structures are simple in terms of geometry, the idea is, that the combination of openGEO with software that is based on an interpolation algorithm would facilitate the modelling process. As a first approach, simple geological structures were modelled in SKUA-GOCAD and merged with the model in openGEO. Here we present first results from combining both software packages in the described way. We used salt structures and their complex inner layers for testing the developed workflow. Thus, we are here introducing a more efficient approach compared to the sole use of openGEO and add a new level of flexibility. The workflow can potentially be applied to the 3D modelling in other geologically complex settings where a high degree of precion is required.

The creation and application of 3D geological models has become increasingly important within the geological surveys in recent years. In the joint project TUNB (Tieferer Untergrund Norddeutsches Becken - Deeper Underground North German Basin), the geological surveys of northern Germany together with the Federal Institute for Geosciences and Natural Resources (BGR) created a coordinated and largely border-harmonised 3D geological model of the North German Basin for their respective state areas.

The objective of this presentation is to describe the approach to develop a generalised 3D geological model from the base Zechstein to the Tertiary of Lower Saxony based on heterogeneous and inconsistent data within this project. The data basis for the current model was the predecessor model GTA3D, digitally available borehole data, depth migrated 2D and 3D seismic data and supplementary data such as thickness and structural maps of lithostratigraphic units. 3D geological modelling was carried out with Emerson SKUA-GOCAD, taking into account the project-related generalisation specifications and geological plausibility. The problem of inconsistencies occurring in the input data due to their different sources, quantity, and quality could not be solved by automated procedures. Instead, this was often subject to the geological expertise of the modeller, who took into account the regional geological conditions to weight the data and create a model that is as free of contradictions as possible. We demonstrate how the integration of new data led to changes in the geometry of salt structures and lithostratigraphic horizons with respect to the predecessor model.

Attributed 3D volumetric models are important tools for geothermal exploration, subsurface storage of natural gases and waste and for risk management (e.g. contamination of ground water or induced seismicity). Of special interest are lithological attributes, which reveal important evidence on characteristics of deep aquifers and reservoir rocks and support project planning.

Therefore, we created attributed 3D volumetric models, which base on a detailed 3D structural geological model of the Altmark region (North German Basin) comprising 31 horizons from base Zechstein to Quaternary. For this purpose, information from lithologic-paleogeographic maps was transferred to the volume models by defining categorial properties. Shale fractions could be qualitatively estimated from the petrographic descriptions and quantitatively confirmed using gamma ray logs. Subsequently, a fault seal analysis was performed on the basis of the lithofacies model. Calculation of the juxtaposition parameter and smear gauge ratio (SGR) provides information on the faults transmissivity and the clay smearing of permeable fault segments.

The resulting attributed 3D models reveal essential information on geometry and characteristics of deep aquifers and reservoir rocks, as well as potential fluid pathways or sealing functions across faults in the Altmark region. Furthermore, extracted lithological information and attributed fault cutoff lines allow a detailed representation of subsurface parameters and the fault network on 2D maps. The results thus form the basis for large information systems and databases providing FAIR and easy to use information for further planning and prospection efforts.

Chromites from ophiolites and layered intrusions show a wide variety in Cr#, Mg# and Cr/Fe ratios. These ratios provide information on the genesis of the chromite deposits e.g. the place of formation.

By means of µ-EDXRF this information can be obtained in a very quick way from cut hand specimen.

Unfortunately, chromites show a number of very intensive diffraction signals due to the polychromatic beam of the µ-EDXRF system, which even after calculating the minimum of two detectors has still some influence on the chemistry of a single chromite grain.

To reduce this problem, chromite aggregates were segmented and for each individual grain, the shapes were used to calculate the mean spectra for both of the detectors (D1/D2), the minimum (min) of both, the mean, the detector minus minimum of both (D1/2-min) to localize the position of the diffraction signals in the spectrum.

All individual grain D1 and D2 spectra are plotted against each other to detect those grains showing a minimum of diffraction, to reduce the diffraction impact on the chemical signal.

Assuming that the chemical pattern of chromite grains within a texturally homogeneous sample should not be to extreme regarding Cr# and Mg# those grains of minimum D1/D2 deviation were selected to represent the chromite chemistry. Validation is done by microprobe analysis.

In a second step these “pure” pattern of selected samples referring to individual tectonic levels of an ophiolite are used as endmembers for hyperspectral classification of chromite of various samples into individual groups/tectonic levels.

Chemical reactivity, mobility, and bioavailability of manganese (Mn) in the environment depend crucially on its speciation. Despite the broad application of X-ray absorption spectroscopy (XAS) to environmental samples, studies covering the identification and quantification of Mn species in soils are surprisingly scarce. In this study, we analyzed 32 organic and inorganic Mn reference compounds by Mn K-edge (6,539 eV) XAS to assess the potential of XAS to differentiate various Mn coordination environments in soils. X-ray absorption near-edge structure (XANES) spectra of reference compounds were evaluated for the oxidation state of Mn using linear combination fit analysis. Results of this analysis were validated by redox titrations. The average local coordination environment (<5 Å) of Mn was analyzed by shell-fitting of extended X-ray absorption fine structure (EXAFS) spectra. Based on spectroscopic data and statistical data analysis, Mn reference compounds were grouped into physically and/or chemically meaningful clusters with diagnostic spectral features. Our results show that XANES spectroscopy can accurately determine the average oxidation state of Mn within 0.12 valence units. EXAFS spectroscopy is capable of differentiating at least three major Mn species groups, which include Mn(III/IV) manganates, Mn(III) oxyhydroxides and organic Mn(III) compounds. Using this information, we elucidated the oxidation state and local coordination environment of Mn in Cambisols, Luvisols, and a Stagnosol (L, O, A, B, and C horizons). Our talk will highlight the capabilities and limitations of XAS in analyzing Mn speciation of bulk soils and provide a guide for scientists exploring the biogeochemical Mn cycle in soil environments.

Spatially detailed surface analysis of geological samples and drill cores offers insight into element and mineral distributions on large scales, an important information in ore exploration processes.
Laser Induced Breakdown Spectroscopy (LIBS) is an uprising technology that allows fast in-situ geochemical measurements directly on a sample surface under atmospheric conditions. Since nearly no sample preparation is needed, the technology is suitable for spatially-resolved measurements on large samples such as drill cores. LIBS also allows the detection of light elements like Li, an important element due to the increasing amounts needed for battery production of all kinds. Nevertheless, interpreting LIBS data is challenging, since various physical and chemical matrix effects do not allow a straightforward analysis of heterogeneous material. Especially quantification remains problematic.
We used a LIBS drill core scanner (Nd:YAG Q-switched 20Hz 1064nm laser and a high-resolution 285-964nm Echelle spectrometer) for 1D profile measurements of 10 consecutive drill core meters from the Rapasaari Li-deposit in Finland. The deposit covers Li-bearing spodumene and muscovite pegmatite, from which five large samples were measured with high resolution in 2D, as well. Small-scale ICP-MS mappings were used as pixel-matched quantitative reference measurements of Li concentrations. They were successfully co-registrated with the LIBS measurements, which enabled matrix-matched quantification using chemometric quantification models.

MC-ICP-MS has become the clearly dominant technology in ²³⁰Th/U-dating over the last 20 years. The ongoing increase in measurement performance allows for ε-precision by now (Andersen et al., 2004; Cheng et al., 2013) and enabled the production of a large amount of datasets and insights covering a broad range of fields. Despite this large database, systematic studies on the impact of individual corrections on the raw data, long-term instrumental stability and on data processing routines are still sparse.

We present the measurement and data analysis protocols developed and applied at the Institute for Environmental Physics at Heidelberg University and examine the contribution of individual corrections, such as tailing and hydride correction, to the total uncertainties of the atomic ratios ²³⁰Th/²³⁸U and ²³⁴U/²³⁸U and of the ages for this procedure. As demonstration examples, three different speleothem samples of different U and Th concentrations and ages were chosen. This puts specific quantitative constraints on general findings as the dominance of tailing correction.

Long-term instrumental stability is examined by compiling a multi-year dataset of (²³⁰Th/²³⁸U) and (²³⁴U/²³⁸U) for the Harwell-Uraninite 1 (HU-1) reference material of more than thousand measurements which is then used for the recalibration of the inhouse ²²⁹Th, ²³³U and ²³⁶U spike. Lastly, we present a Python-based GUI for the combined evaluation of mass-spectrometric data and age determination that offers high flexibility with regard to the variation of input constants, such as the initial (²³⁰Th/²³²Th) used for detritus correction.

Documentation of sample collection and instrument deployment in the field is time-consuming, error-prone and laborious. Even though best practices in research data management suggest that data should be captured in a structured digital format as early as possible in the data life cycle, fieldwork often suffers a digitisation bottleneck.

Mobile applications are one solution to overcome the digitisation bottleneck. They allow data capture in the field, including automatic capture of contextual data like campaign information, operator, date and time, geographic position, etc. On the other hand, systematic field campaigns commonly follow specific workflows and no single application can cover all requirements. Development costs of creating a new software package for each field campaign are also prohibitive.

Instead of a specific mobile application, we use the FAIMS application framework that allows fast production of mobile data acquisition applications that are tailor-made for their intended use cases. In field deployments, we demonstrated that in combination with machine-readable sample labels the sample documentation workflow could be streamlined and the time needed could be reduced by 50%.

The FAIMS application framework allows data, collected offline, to be synchronised between devices and a server, facilitating both data sharing between campaign participants and securing against data loss. The collation of data in this manner also allows data to be fed back into field operations to support decision-making, e.g., to optimise sampling strategies in a dynamic environment or based on newly acquired data.

GEOROC is a leading open-access source of geochemical and isotopic datasets and has facilitated thousands of peer-reviewed publications and new avenues of geochemical research. The new Digital Geochemistry Infrastructure (DIGIS) concept of GEOROC 2.0, an integral part of the NFDI4Earth initiative, will continue and enhance the existing data collection by generating a connected platform that meets future challenges of digital data-based research and provides advanced service to the community.

Our approach is to (1) realign GEOROC with current and future demands in digital geochemical research, especially regarding FAIR (findable, accessible, interoperable, reusable) principles; (2) provide this service with future-ready, adaptable IT infrastructure; and (3) identify, develop and recommend good-practice rules for the curation of physical samples linked to the GEOROC 2.0 platform. DIGIS will implement an interoperable metadata model as well as data and metadata exchange via standardised application interfaces (APIs). The scientific development of GEOROC 2.0 and the re-organisation of its IT infrastructure will enable a more diverse range of geochemical data, improving integration in other research disciplines such as soil science, remote sensing, and archaeometry. The DIGIS concept for GEOROC 2.0 includes open access to end-to-end text and data mining, integration of IGSNs and data DOIs, multi-way data harvesting capabilities, and state-of-the-art connectivity to other databases. By ensuring continued open access to a FAIR database, DIGIS aims to facilitate sustainability in future Environmental and Earth Science research.

Today, research data is widely available in digital form, datasets are easily accessible online and the dataset creator should consider it advantageous as this leads to greater uptake. However, the downside is that digital datasets can be easily copied, duplicated in multiple places, and re-published through more than one repository or service. Particularly with web services, mirroring resources is a common practice, especially in online GIS packages and dashboards. ‘Copy WMS link’ buttons are common, but these often only provide access to the service endpoints: any information about the owner, licence, accreditation, citation etc is not carried with the data. Increasingly poor practices in republication and duplication are leading to exactly the same versions of data/metadata being available in multiple places: some replications are assigned new DOIs, without cross-referencing the original DOI.

Increasingly funders ask for information about usage and impact of datasets/data acquisition campaigns they funded. Journal publishers now require that appropriate credit be given to whoever collected, curated and/or preserved the data in a publication. Best practices are currently poorly defined: researchers are raising issues on ethics and asking if we need to rethink data licencing.

There is clearly a need for community agreed documentation of best practices for the identification of data aggregations, data re-publication and mirroring of data to multiple sites. For ethical scientific research there is an urgent need to be able to identify the authoritative or canonical version of a dataset and ensure correct attribution and citation of any data source.

AuScope is Australia’s National Geoscience Research Infrastructure Program and seeks to provide a world-class research physical and digital infrastructure to help tackle Australia's key geoscience challenges. Launched in 2007, AuScope’s data-generating infrastructures range from VLBI telescopes to geochemistry/geochronology laboratories and geophysical data acquisitions. To utilise data collected by these infrastructures and equivalents elsewhere, the Australian Geoscience Research and Government communities have collaborated on building a suite of data portals, tools, software and virtual laboratories that enabled discovery of data and tools and process them using online workflows.

Over time, it was recognised the nature of research was changing - it has become more transdisciplinary and data-intensive. Processing and storage capacities have multiplied enabling processing of higher resolution datasets, new tools like notebooks and containerisation have become available, and the demand for mobile solutions is growing. Online portals with prefixed workflows no longer supported research innovation: researchers wanted greater flexibility to discover their own data sources and combine them with tools of their choice and process where most optimal.

In 2017, the AuScope Virtual Research Environment (AVRE) was launched to support these new ambitions. The aspiration was to realise a service-oriented science platform that will allow users to choose their own data sets and tools and empower next generation data assimilation and modelling. Through using international standards and protocols, AVRE will ensure connection with equivalent infrastructures in the marine, bio, environmental, geospatial, etc communities, as well as seamlessly integrate with relevant international research infrastructures such as ENVRI, EPOS, EarthScope, etc.

In less than one decade the open-access data journal Earth System Science Data (ESSD, a member of the Copernicus Open Access Publisher family) grew from a start-up venture into one of the highest-rated journals in global environmental science. Stimulated by data needs of the International Polar Year 2007-2008, ESSD now serves a very broad community of data providers and users, ensuring that users get free and easy access to quality data products and that providers gain full scientific credit for preparing, describing and sharing those products via a peer-reviewed data description article. Adopting technology and practices from research journals,

ESSD moved data publication from an abstract concept to a working enterprise, bridging the worlds of data and research; several publishers now support data-sharing journals. ESSD serves as a prominent voice for, and useful example of, emphatic fully-free fully-open global data access. ESSD publishes comprehensive data descriptions, certifying quality and ensuring accessibility of the described data or database and allowing users to pursue subsequent analysis and interpretation with confidence. As ESSD works with data providers and data repositories to confront challenges and barriers, increasing submission numbers indicate that the concept of sharing data through formal publication meets a strong community need.

Understanding earth materials is critical to creating a sustainable, carbon-neutral society due to their involvement in many vital processes. Earth materials control the feasibility of subsurface energy storage, geothermal energy extraction, and are a source of critical elements. However, perturbations to geological systems can also result in hazards, such as human-induced earthquakes. If we want to tackle current, pressing scientific questions related to sustainable development for a circular economy, there is an urgent need to make multi-scale, multi-dimensional characterisations of earth materials available to a broad spectrum of earth-science disciplines. In addition to the society relevant topics, the properties of earth materials determine how the Earth works on the most fundamental level.

To overcome this challenge, 15 European electron and X-ray microscopy facilities join forces to establish EXCITE (Electron and X-ray microscopy community for structural and chemical imaging techniques for earth materials; www.excite-network.com).

EXCITE enables access to high-end microscopy facilities and to join the knowledge and experience from the different institutions.

EXCITE develops community-driven technological imaging advancements that strengthen and extend the current implementation of leading-edge microscopy for earth-materials research.

EXCITE integrates joint research programmes with networking, training, and transnational access activities, to enable both academia and industry to answer critical questions in earth-materials science and technology.

As such, EXCITE builds a community of highly qualified earth scientists, develops correlative imaging technologies and provides access to world-class facilities to new and non-expert users that are often hindered from engaging in problem-solving microscopy.