ALBERT

Description: Near Reykjavik/Iceland, a "soft stimulation” geothermal experiment was performed in the frame of the DESTRESS project in 2019. The installed seismic stations consist of short period, and borehole stations in and around Geldinganes, NE of Reykjavik. The task of this network is the monitoring of the seismic events in the area around the stimulation site. The installation started in late 2018 with 6 short period stations (Reykjavik Energy). Since July 2019 additional seismic stations were integrated as a small scale array on the island Geldinganes and additional short period stations. A borehole geophone chain was installed with 17 short period 3-component geophones with a vertical spacing of 10 meter in the depth interval 1040m to 1200 m. Waveform data are available from the GEOFON data centre, under network code YG, and are embargoed until January 2025.

Description: The Bransfield Strait is a seismically active extensional rift located between the Antarctic Peninsula and the South Shetland Islands. The Strait is partly located on continental crust including areas within the transition to seafloor spreading. The amphibious seismic network BRAVOSEIS is an international effort focused on the seismological research of submarine volcanoes and rift dynamics in the Bransfield Strait. This network is the onshore component of the entire network consisting of 15 broadband land stations deployed in the South Shetland Islands and Antarctic Peninsula between January 2018 and February 2020. The offshore components (network code ZX) include 9 broadband ocean bottom seismometers (OBS) across the Central Bransfield Basin and a group of 6 hydrophone moorings spanning the rift area of 200 x 100 km2, with inter-station distance of ~30 km. Additionally, a smaller offshore array consisting of 15 short-period OBSs with an aperture of 20 km and a narrow inter-station distance of ~4 km was deployed around the Orca submarine volcanic edifice south of King George Island. The data will be used to study the geodynamics of the Bransfield Strait and the evolution of the incipient rifting zone in the domain where extension has been suggested. Seismological methods will include earthquake location, source mechanism, surface wave analysis with ambient noise and earthquake data, receiver function and shear wave splitting. The results may shed light on the crustal structure and tectonic regime in the region and image the location and extent of magma accumulations related to submarine volcanic structures. Finally, the results should provide clues to assess the internal processes that occur in the submarine volcanoes of the area undergoing rifting. Waveform data are available from the GEOFON data centre, under network code 5M and are embargoed until Mar 2024. Acknowledgments: We thank all participants in the BRAVOSEIS 2018, 2019, and 2020 cruises, with a special acknowledgement to Capt. Jose Emilio Regodon and his crew at R/V Hesperides; Capt. Juan Carlos Hernandez and his crew at Sarmiento de Gamboa; Miki Ojeda, Ezequiel Gonzalez, and all the UTM staff involved in the planification and realization of the surveys. We also thank the Spanish Polar Committee and institutions involved in the management of the Spanish Antarctic campaigns and the development of the Spanish Polar Program. We are grateful for the help and support that we always find in the personnel of the Antarctic Bases, especially the Spanish Bases Juan Carlos I and Gabriel de Castilla.

Description: Oldoinyo Lengai in the North Tanzanian Divergence is the only active natrocarbonatite volcano world-wide and presents an important endmember magmatic system in a young rift segment of the East African Rift System. This volcano typically experiences long-duration episodes of natrocarbonatitic effusions with intermittent short-duration explosive eruptions. To better understand the role of the stress interactions and magma plumbing on the eruptions dynamics, this study aims to constrain the subsurface magmatic architecture of Oldoinyo Lengai, and a zone of ongoing seismicity and intrusive activity below the extinct 1 Ma-old Gelai shield volcano and active Naibor Soito monogenetic cone field. Waveform data are available from the GEOFON data centre, under network code 9J, and are embargoed until November 2025.

Description: On 26th of November 2019 an Mw 6.4 earthquake ruptured near the port town of Durres, only 25 km from Tirana, the capital of Albania. The earthquake caused major damage and killed 51 people, making it the deadliest earthquake in 2019 worldwide. The mainshock was relatively deep (~25 km) and of thrust type. In December 2019, a Hazard and Risk team (HART) from German Center for Geosciences (GFZ), Karslruhe Institute of Technology (KIT) in cooperation with the Institute of Geosciences, Energy, Water and Environment (IGEWE) of the Polytechnic University of Tirana, Albania installed a 30-station seismic network in the epicentral region to record aftershocks. Stations were equipped with short-period (1 Hz or 4.5 Hz) 3-component seismometers and CUBE data loggers recording continuously 100 sps. Waveform data are available from the GEOFON data centre, under network code 9K under CC-BY 4.0 license and are embargoed until January 2024.

Description: Was ist Fernerkundung? Was sehen Satelliten? Und wie können optische Satellitendaten genutzt werden? Diese Fragen und mehr beantwortet das erste Dokument aus der Reihe SAPIENS: Satellitendaten für Planung, Industrie, Energiewirtschaft und Naturschutz. Wir geben eine kurze Einführung in die Fernerkundung mit vielen weiterführenden Weblinks und Anwendungsbeispielen.

Description: Proficiency testing (PT) is one of the few ways for an analytical laboratory to assess data quality under routine operating conditions. Here we report the results of Round 1 of the G-Chron PT programme, which is sponsored by the International Association of Geoanalysts. G-Chron is the first PT scheme devoted to the U-Th-Pb dating of mineral phases, primarily zircon, in geological materials. In this first round of G-Chron a total of 72 geochronology laboratories received the test material “Rak-17”, which previously had been characterized by seven well-established isotope dilution TIMS laboratories. A total of 63 of the PT participating laboratories reported data by the 15 December 2019 deadline. Here we both report and assess the measurement results submitted to this round. Our analysis provides a means for participating laboratories to assess their individual performance in relation to the isotope ages assigned, the experimental fitness-for-purpose criteria proposed by the scheme’s organisers and the results of similar laboratories participating in this round.

Description: A c. 2.4 Ga microbialite reef complex within the Turee Creek Group (TCG) in Western Australia was deposited in the aftermath of the Great Oxidation Event (GOE). The diverse reef contains the first appearance of thrombolites, a complex deep water microfossil assemblage, and the oldest shallow water sedimentary phosphorous deposit [1, 2, 3]. Silica is present throughout the reef, as microcrystalline quartz in thrombolites, fine chert preserving the deep water microfossil assemblage, and as euhedral quartz crystals within phosphorous-rich peloids and pebbles [1, 2, 3]. Petrographic examination indicates some relatively early silica phases. Si isotope analysis will be used to evaluate the effect of re-equilibration by Proterozoic sea water and pore fluids on the cherts and quartz grains within this reef, to determine whether primary information (such as sea water temperature, pH, and salinity [4, 5]) can be retained. Here we present a wide range of recorded δ30Si from -2.8 to 4.1 ‰, which is typical of Precambrian cherts [4, 5, 6]. It was recently demonstrated that low temperature re-equilibration of Si isotopes between amorphous and aqueous states readily occurs in water with high ionic strength and that is supersaturated with Si [4]. Since these units were deposited before the advent of silicifers (e.g. diatoms), the ocean would have been supersaturated with silica [4, 5]. Re-equilbration is likely to have occurred, and it is possible that some isotope values reflect the sea water, or diagenesis, rather than the process that first precipitated the silica or the source of silica. By determing how much of an effect re-equilibration has had, we can try to determine what useful, primary information is retained and what the environment was like during the GOE.

Description: IGMAS+ is a software for 3-D modelling of potential fields and its derivatives under the condition of constraining data and independent information. It comes with tools for forward and inverse modelling. IGMAS+ has a long history starting 1988 and has seen continuous improvement since then with input by many contributors.

Description: The rapid increase in energy demand in the city of Reykjavik has posed the need for an additional supply of deep geothermal energy. The deep-hydraulic (re-)stimulation of well RV-43 on the peninsula of Geldinganes (north of Reykjavik) is an essential component of the plan implemented by Reykjavik Energy to meet this energy target. Hydraulic stimulation is often associated with fluid-induced seismicity, most of which is not felt on the surface but which, in rare cases, can be a nuisance to the population and even damage the nearby building stock. This study presents a first-of-its-kind pre-drilling probabilistic induced seismic hazard and risk analysis for the site of interest. Specifically, we provide probabilistic estimates of peak ground acceleration, European microseismicity intensity, probability of light damage (damage risk), and individual risk. The results of the risk assessment indicate that the individual risk within a radius of 2 km around the injection point is below 0.1 micromorts, and damage risk is below 10−2, for the total duration of the project. However, these results are affected by several orders of magnitude of variability due to the deep uncertainties present at all levels of the analysis, indicating a critical need in updating this risk assessment with in situ data collected during the stimulation. Therefore, it is important to stress that this a priori study represents a baseline model and starting point to be updated and refined after the start of the project.

Description: In the Koyna–Warna region, western India, an enormous number of microearthquakes was detected automatically on borehole records. Most of these events could not be identified on the surface network by a routine approach based on visual inspection primarily due to signal attenuation and the presence of noise. In this work, we implemented an automatic detection workflow to analyze the time series of an earthquake sequence that has clear foreshock and aftershock activity associated with an Mw 4.0 earthquake that occurred on 3 June 2017. Further, we applied a nested grid‐search algorithm to constrain the absolute earthquake locations. For about one month of data, a total of ∼1500 earthquakes were detected based on the automatic detection process, out of which ∼1000 earthquakes were locatable. All event detections, P‐wave and S‐wave phase readings were manually inspected and refined to ensure their quality. Previously, only about 435 events were well located based on the visual inspection approach for the same time period. Also, we analyzed repeated earthquakes based on waveform similarity leading to an improvement in the relocations of earthquakes of the aforementioned earthquake sequence. The relocated seismicity aligns parallel to a deep‐reaching lineament derived from recent investigations using airborne light detection and ranging measurements.

Description: Heat waves have tremendous ecological and socioeconomic consequences for many countries and initiate complex event chains that reach from the land surface to the upper atmosphere. Although it is well known that global change affects the Earth and environment on many different time and length scales, currently, only very limited knowledge is available on the importance of such distinct dynamic events for the long-term development of the Earth system. To investigate the impact of extended heat periods and droughts on our terrestrial ecosystems and natural resources, the Helmholtz MOSES project implements a modular infrastructure that is designed to capture such highly dynamic events in event-driven campaigns. As part of this infrastructure initiative a new hyperspectral thermal instrument, the Telops Hyper-Cam LW, was recently acquired at the Potsdam German Research Centre for Geosciences (GFZ) and capabilities for airborne surveys, laboratory and field deployment, as well as data processing in the context of heat wave impacts are currently developed. The Telops Hyper-Cam LW is a Fourier-transform imaging spectrometer (~8–12 μm) with adjustable spectral resolution from 0.25 to 150 cm−1 that can be operated at various scales from ground and airborne platforms. The hyperspectral longwave infrared shows great potential for the characterization of soil and vegetation properties and their variability related to heat wave impacts. However, this spectral imagery can only be used to fullest advantage when the signal is corrected, e.g. path radiance of the atmosphere, as well as the downwelling radiance component have been removed from the measured signal and temperature is separated from emissivity. In this context, this contribution describes the recent developments at GFZ toward (i) The development of suitable field sampling strategy & protocols related to the acquisition of field thermal hyperspectral data including calibration and validation measurements, (ii) Establishment of preliminary protocols for field data processing to temperature and emissivity, (iii) Test and mounting of the Hyper-cam on the Cessna-T207A airborne platform from the Free University Berlin (FUB) and (iv) Flight testing and calibration, and establishment of preliminary protocols and strategies for the development of a processing chain from raw data to temperature and emissivity imagery and extraction of relevant thematic parameters. In particular, first results will be shown based on the MOSES/ScaleX-2019 campaign where field Hyper-Cam measurements were acquired in different configurations at the Fendt grassland test site located in the German Pre-Alpine foreland. Different approaches for temperature emissivity separation are tested and compared, e.g. normalization emissivity method and spectral smoothness based emissivity separation. Furthermore, calibration and validation activities are presented in the frame of several airborne surveys over different targets to correct and validate the thermal signal. Preliminary airborne results will be shown over different locations in Germany and Greece that indicate good geometric and radiometric data accuracy, as well as high potential for the differentiation of surface materials from the spectral emissivity and surface temperature.

Description: The dataset is composed of Neo HySpex (VNIR/SWIR) hyperspectral imagery acquired during airplane overflights on June 6th, 2015 covering the Omongwa Pan located in the South-West Kalahari, Namibia. The dataset includes three cloud-free flight lines with 408 spectral bands ranging from VNIR to SWIR wavelength regions (0.4-2.5 µm). The dataset also includes Level 2A EnMAP-like imagery simulated using the end-to-end Simulation tool (EeteS). The overall goal of the campaign was to acquire imagery over the Omongwa Pan and use the spectral reflectance for the analyses of surface sediments, specifically the mineralogical composition of exposed surface evaporites / salts on the airborne and spaceborne scale. The data are highly novel and can be used to test estimation of surface sediment properties in a highly saline and dynamic environment.

Description: The dataset is composed of Neo HySpex (VNIR/SWIR) hyperspectral imagery acquired during the GFZ/DIMAP Geoarchive airborne campaign on June 6th, 2015 covering the Omongwa salt pan located in the South-West Kalahari, Namibia. The dataset includes 9 merged cloud-free flight lines with 408 spectral bands ranging from VNIR to SWIR wavelength regions (0.4-2.5 μm). The dataset also includes Level 2A EnMAP-like imagery simulated using the end-to-end Simulation tool (EeteS). The overall goal of the campaign was to test the potential of advanced optical hyperspectral remote sensing, or imaging spectroscopy, for the analysis of surface processes in the Omongwa salt pan and for the quantification of surface sediments. Specifically, the mineralogical composition of exposed evaporites such as halite, gypsum and calcite were investigated at the airborne and spaceborne scale, associated with comprehensive field campaigns, ich which spectral reflectance and ground-truth chemical data of field samples have been collected. The data are highly novel and can be used as testbeds for the development and validation of retrieval algorithms based on air- and space-borne hyperspectral imagery for estimation of surface sediment properties in a highly saline and dynamic environment.

Description: Viscoelastic deformations of an earth structure in response to a time-varying surface load are analyzed in glacial isostatic adjustment (GIA). When solving this problem, aspects like flexure of the lithosphere and retarded response of mantle material become evident. Quantified are these by flexural rigidity and relaxation times. The concepts partly lose their relevance when changing from a 1D earth structure (only radial variations) to a 2D or a 3D earth structure (lateral variations). In regions like Fennoscandia and Laurentide, which are affected by GIA, lateral variations of the lithosphere and mantle structure are moderate and, so, the application of a 1D earth structure is widely accepted. But, also for these two regions one has to keep in mind that the respective 1D earth structures differ and that such an approximation mainly holds in the central part of the respective region. In contrast, lateral variations or a local structure of different viscosity have to be considered in areas like Patagonia, Antarctica or Alaska which is located above tectonic activity or covers a region with significant lateral changes in earth structure. But, already for the two former examples one has to keep in mind that the respective 1D earth structures inferred from GIA modelling differ between the two regions. Focusing on the relaxation behavior and the mantle-material transport, we discuss the effect of lateral variations on the deformation process. We will assess to which extent a 1D earth structure can represent lateral variability in structural features, and, at which point a 3D earth structure has to be considered. Such questions are of concern, when discussing GIA for geodetic applications as well as in earth system modeling as this study contributes to the climate modeling initiative Palmod.

Description: As part of the Onshore Energy Systems Group’s program, organic maturation levels were determined using polar compounds from potential source rocks from the Georgina and Canning basins. The Early Paleozoic organic matter is devoid of the vitrinite maceral so unsuitable of the measurement of the industry-standard vitrinite reflectance (Ro%) measurement.

Description: Assessing resources of enhanced geothermal (EGS) or medium deep geothermal systems (MDGS) for direct heat use and underground thermal energy storage (UTES) is a challenging task where usually diverse data sets of multiple origin and scale have to be compiled to obtain a comprehensive conceptual model of the subsurface, its structure and its properties. Within the research project “Hessen 3D 2.0” (BMWI-FKZ: 0325944), which aims to enhance the assessment of the prospective risk (‚Fündigkeitsrisiko’) for these kinds of geothermal projects, we established a workflow to implement and analyse such broad data sets. In a first step, comprehensive datasets of physical rock-, fluid- and reservoir properties are compiled which are based on investigations on relevant reservoir analogues, hydraulic test data from boreholes and borehole geophysical logs. The second step comprises the development of 3D geological models from a combination of borehole data, geological cross sections, seismic profiles, gravity and geomagnetic anomalies and geological maps to achieve the required detail on subsurface structure. This is prerequisite to distinguish the potentially usable reservoir units both within the crystalline or metamorphic basement and the sedimentary cover. Geostatistical analysis of the acquired comprehensive geothermal database is performed in a third step of the workflow; this allows for a parametrization of the geological model, for thermohydraulic subsurface modelling, and finally for the geothermal resource assessment. Such models, which consider the variability of rock and reservoir and fluid properties provide a thorough understanding of the subsurface temperature distribution, the dominant heat transport processes and hydraulic conditions. Finally, under consideration of both technical and economic boundary conditions and the statistics for the different relevant reservoir properties of the different geological units, assessment of hydrothermal, petrothermal and UTES potentials is performed directly with the 3D model. Therefore, a multiple-criteria approach, which assesses the quality of various rock and reservoir properties and their relevance for the different geothermal utilizations is implemented. This 3D-grid based method can be used for an identification and visualization of different geopotentials using various parameters to determine each potential. Thereby, to specify the grade of each potential under technical and economic requirements, threshold values for each parameter are defined. The approach described here allows for a stochastic assessment of the geothermal resources of a particular site of interest, including the determination of the probability of success and it provides the necessary numbers to attract investors to geothermal projects.

Description: Microwave signals passing through the troposphere are delayed by refraction. Its high variations, both in time and space, are caused mainly by water vapor. The tropospheric delay used to be considered only as a source of error that needed to be removed. Nowadays, these delays are also a source of interest, for example, tropospheric delays or integrated water vapor information are being assimilated into nowcasting or numerical weather prediction (NWP) models. Moreover, long time series of tropospheric observations have become an important source of information for climate studies. On the other hand, the meteorological data is supporting the space-geodetic community by providing models that can be used to reduce the troposphere impact on the signal propagation. There are several ways of observing the troposphere, especially considering water vapor. First one are the classical meteorological: in-situ measurements, radiosondes or radiometers, from which we can sense directly the amount of water vapor. Another, indirect way of observing the water vapor distribution is by using the Global Navigation Satellite Systems (GNSS). This method is called GNSS meteorology. Other microwave techniques such as Very Long Baseline Interferometry (VLBI), Interferometric Synthetic Aperture Radar (InSAR) or space-based Radio Occultations (RO) can also be used in a similar way to GNSS. This contribution presents an overview of the troposphere sensing techniques with examples of their applications. We present a multi-comparison of the tropospheric products, i.e. refractivity, tropospheric delays in zenith and slant directions and integrated water vapor. The integration of the different data sources often leads to an improved accuracy of the tropospheric products but requires a careful preparation of data. The combination of the data sources allows for using techniques of complementary properties, for example InSAR with very high spatial resolution with GNSS observations of high temporal resolution. With the emergence of new technologies, some traditional ways of tropospheric measurements can be augmented with the new methods. For example, we have tested meteo-drones as an alternative to radiosondes. The comparisons with GNSS data shows a good agreement of the drone and microwave data, even better than with radiosondes.

Description: By performing high pressure and temperature experiments, this study clarifies the suprasolidus phase relations of the nominally anhydrous Ca-Mg-CO3 system at 6 GPa showing that Ca-Mg-carbonates will (partially) melt for temperatures above ~1300 ℃. Further, partition coefficients for Li, Na, K, Mn, Fe, Sr, Ba, Pb, Nb, Y and rare earth elements between dolomite and dolomitic melt, Ca-magnesite and dolomitic melt and magnesite and dolomitic melt are established.

Description: Eoarchean to Rhyacian crust is preserved in the São Francisco Craton of eastern Brazil. To position this crustal segment in paleocontinental reconstructions, precise, accurate and robust geochronological data are necessary, especially for the diverse regional-scale mafic dyke swarms that crosscut the cratonic basement. This geochronological database can then be used to construct a magmatic barcode and compare it to the barcode of other cratons around the world, in search of similarities that might help to position these pieces in the paleocontinental puzzles. New Usingle bondPb SHRIMP contextual in-situ (thin section) dating of baddeleyite and zircon from six samples of three different dyke swarms in the southern São Francisco Craton, in addition to novel lithogeochemical and Ndsingle bondSr isotopic data, allow to pinpoint dyke emplacement at ca. 2.55 Ga (Lavras I swarm; εNd(t) = −6 to +2; TDM not calculable), ca. 1.8–1.7 Ga (Pará de Minas I and II dyke swarms; εNd(t) = −10 to −5; TDM = 2.5–3.0 Ga) and at ca. 900 Ma (Formiga dyke swarm; εNd(t) = −7 to 0; TDM = 1.4–2.3 Ga). The new geochronological data suggest a link between the regional dyke swarms and extensional stresses during the onset of crustal rifting related to the evolution of the Minas, Espinhaço and Macaúbas basins, respectively. A barcode comparison shows strong similarity between the São Francisco and North China cratons (Lavras-Taipingzhai/Naoyumen swarms, Pará de Minas-Taihang/Miyun swarms, Formiga/Pedro Lessa-Sariwon/Dashigou swarms; and possible correlations of the poorly dated 2.2–2.0 Ga Paraopeba swarm with similar aged swarms in North China), suggesting proximity of those two cratonic blocks, whether they were part or not of Proterozoic paleocontinents such as Columbia and Rodinia. The novel geochronological data support previous interpretations based on paleomagnetic data and provide further refinements of the geochronological record of the southern hemisphere cratonic blocks, allowing for better-tied global correlations.

Description: Accessory mineral thermometry and thermodynamic modelling are fundamental tools for constraining petrogenetic models of granite magmatism. U–Pb geochronology on zircon and monazite from S-type granites emplaced within a semi-continuous, whole-crust section in the Georgetown Inlier (GTI), NE Australia, indicates synchronous crystallisation at 1550 Ma. Zircon saturation temperature (Tzr) and titanium-in-zircon thermometry (T(Ti–zr)) estimate magma temperatures of ~ 795 ± 41 °C (Tzr) and ~ 845 ± 46 °C (T(Ti-zr)) in the deep crust, ~ 735 ± 30 °C (Tzr) and ~ 785 ± 30 °C (T(Ti-zr)) in the middle crust, and ~ 796 ± 45 °C (Tzr) and ~ 850 ± 40 °C (T(Ti-zr)) in the upper crust. The differing averages reflect ambient temperature conditions (Tzr) within the magma chamber, whereas the higher T(Ti-zr) values represent peak conditions of hotter melt injections. Assuming thermal equilibrium through the crust and adiabatic ascent, shallower magmas contained 4 wt% H2O, whereas deeper melts contained 7 wt% H2O. Using these H2O contents, monazite saturation temperature (Tmz) estimates agree with Tzr values. Thermodynamic modelling indicates that plagioclase, garnet and biotite were restitic phases, and that compositional variation in the GTI suites resulted from entrainment of these minerals in silicic (74–76 wt% SiO2) melts. At inferred emplacement P–T conditions of 5 kbar and 730 °C, additional H2O is required to produce sufficient melt with compositions similar to the GTI granites. Drier and hotter magmas required additional heat to raise adiabatically to upper-crustal levels. S-type granites are low-T mushes of melt and residual phases that stall and equilibrate in the middle crust, suggesting that discussions on the unreliability of zircon-based thermometers should be modulated.

Description: The Xiling Sn deposit in eastern Guangdong Province comprises the Fengdishan Sn and the Saozhoudi Sn–Pb–Zn ore blocks and has long been regarded as a volcanic–subvolcanic system related to Sn polymetallic mineralization. Here, we present fluid inclusion microthermometric data from different ore stages and H–O–S isotope data of hydrothermal minerals to constrain the genesis of the Xiling deposit. Fluid inclusions from stage I have Th values from ~ 340 to 420 °C and salinities from ~ 15 to 17 wt% NaCl equivalent, while homogenization temperatures of fluid inclusions from stages II to V range from ~ 150 to 320 °C, and salinities range between ~ 1 and 6 wt% equivalent. The oxygen and hydrogen isotopic composition of quartz and cassiterite (δDfluid − 65‰; δ¹⁸Ofluid 3.6 to 6.3‰) suggest that the ore-forming fluids from stage I have a distinct magmatic signature, whereas those from stage II through stage IV (δDfluid from − 80 to − 49‰; δ¹⁸Ofluid from − 3.7 to 2.5‰) show characteristics of mixing between meteoric and magmatic fluids. Moreover, δ³⁴S values for sulfides from the Fengdishan ore block have a narrow range of 0.6 to 2.5‰ with a mean close to 0‰, consistent with a magmatic sulfur source. By contrast, δ³⁴S values for ore minerals from the Saozhoudi ore block range from 3.4 to 11.5‰, suggesting involvement of a sedimentary sulfur source. In addition, a previous geochronological study has shown that the volcanic–subvolcanic host rocks have an age of 160–170 Ma, while the Sn polymetallic mineralization has an age of about 145 Ma. Our data support a model of mixing of magmatic brine from a hidden granitic intrusion with meteoric water. The S isotope data and the observed temperature gradient of the fluid system suggest that the Sn mineralization is developed in the central part of the ore system, while the Sn–Pb–Zn and Pb–Zn mineralization occurs in the distal part. This finding might have important implications for exploration in the region.

Description: Hydrometric networks play a vital role in providing information for decision-making in water resource management. They should be set up optimally to provide as much information as possible that is as accurate as possible and, at the same time, be cost-effective. Although the design of hydrometric networks is a well-identified problem in hydrometeorology and has received considerable attention, there is still scope for further advancement. In this study, we use complex network analysis, defined as a collection of nodes interconnected by links, to propose a new measure that identifies critical nodes of station networks. The approach can support the design and redesign of hydrometric station networks. The science of complex networks is a relatively young field and has gained significant momentum over the last few years in different areas such as brain networks, social networks, technological networks, or climate networks. The identification of influential nodes in complex networks is an important field of research. We propose a new node-ranking measure – the weighted degree–betweenness (WDB) measure – to evaluate the importance of nodes in a network. It is compared to previously proposed measures used on synthetic sample networks and then applied to a real-world rain gauge network comprising 1229 stations across Germany to demonstrate its applicability. The proposed measure is evaluated using the decline rate of the network efficiency and the kriging error. The results suggest that WDB effectively quantifies the importance of rain gauges, although the benefits of the method need to be investigated in more detail.

Description: Many mountain glaciers carry some amount of rocky debris on them, which modifies surface ablation rates. The debris is typically derived from erosion of the surrounding topography and its supraglacial extent is predominantly controlled by the relative accumulation rates of debris versus snow. Because Global Warming results in shrinking glaciers as well as thawing permafrost worldwide, changes in both rates will most likely affect the evolution of supraglacial debris cover and thus the response of glaciers to climate change. Here, we report 10Be concentrations measured in five amalgamated debris samples collected from the main medial moraine of the Chhota Shigri Glacier, India. Results suggest headwall erosion rates that are ~0.5‐1 mm yr‐1, and apparently increasing (10Be concentrations are decreasing) towards the present. We employed a numerical ice flow model that we combined with a new Lagrangian particle tracing routine to explore the impact of spatial and temporal variability in erosion rates and source areas on 10Be concentrations in the medial moraine. Our modeling results show that neither changes in source areas, related to the transient response of the glacier to ongoing climate change, nor four different scenarios of spatial and temporal variability in erosion rates, could explain the observed trend in 10Be concentrations. Although not accounted for in our modelling explicitly, we suggest that the observed trend could be due to transiently enhanced erosion of recently deglaciated areas, or to greater spatial variability in erosion rates than explored in our models.

Description: In this chapter the application of the curlometer technique to various regions of the inner magnetosphere and upper ionosphere and for special circumstances of sampling is described. The basic technique is first outlined, together with the caveats of use, covering: the four-spacecraft technique, its quality factor and limitations; the lessons learnt from Cluster data, together with issues of implementation, scale size and stationarity, and description of the key regions covered by related methodology. Secondly, the application to the Earth’s ring current region is outlined, covering: the application of Cluster crossings to survey the ring current; the use of the MRA (magnetic rotation analysis) method for field curvature analysis; the use of THEMIS (Time History of Events and Macroscale Interactions during Sub-storms mission) three-spacecraft configurations to sample the ring current, and future use of MMS (Magnetospheric MultiScale mission) and Swarm data, i.e. the case of small separations. Thirdly, the application of the technique to the low altitude regions covered by Swarm is outlined, covering: the extension of the method to stationary signals; the use of special configurations and adjacent times to achieve 2, 3, 4, 5 point analysis; the use of the extended ‘curlometer’ with Swarm close configurations to compute 3-D current density, and a brief indication of the computation of current sheet orientation implied by 2-spacecraft correlations. Fourthly, the direct coordination of Cluster and Swarm to check the scaling and coherence of field-aligned currents (FACs) is outlined.

Description: Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an absolute, real-time estimate of human activities.

Description: Understanding the dynamic evolution of relativistic electrons in the Earth's radiation belts during both storm and non‐storm times is a challenging task. The U.S. National Science Foundation's Geospace Environment Modeling (GEM) focus group ``Quantitative Assessment of Radiation Belt Modeling" (QARBM) has selected two storm time and two non‐storm time events that occurred during the second year of the Van Allen Probes mission for in‐depth study. Here, we perform simulations for these GEM challenge events using the 3‐Dimensional Versatile Electron Radiation Belt (VERB‐3D) code. We set up the outer L* boundary using data from the Geostationary Operational Environmental Satellites (GOES) and validate the simulation results against satellite observations from both the GOES and Van Allen Probe missions for 0.9 MeV electrons. Our results show that the position of the plasmapause plays a significant role in the dynamic evolution of relativistic electrons. The magnetopause shadowing effect is included by using last closed drift shell (LCDS), and it is shown to significantly contribute to the dropouts of relativistic electrons at high L*. We perform simulations using 4 different empirical radial diffusion coefficient models for the GEM Challenge Events, and the results show that these simulations reproduce the general dynamic evolution of relativistic radiation belt electrons. However, in the events shown here, simulations using the radial diffusion coefficients from Brautigam and Albert (2000) produce the best agreement with satellite observations.

Description: The radiation belts of the Earth, filled with energetic electrons, comprise complex and dynamic systems that pose a significant threat to satellite systems. While various models of electron flux both for low and relativistic energies have been developed, the behaviour of medium energy (120‐600 keV) electrons, especially in the MEO region remains poorly quantified. At these energies, electrons are driven by both convective and diffusive transport, and their prediction usually requires sophisticated 4D modeling codes. In this paper we present an alternative approach using the Light Gradient Boosting (LightGBM) machine learning algorithm. The Medium Energy electRon fLux In Earth's outer radiatioN belt (MERLIN) model takes as input the satellite position, a combination of geomagnetic indices and solar wind parameters including the time history of velocity, and does not use persistence. MERLIN is trained on 〉15 years of the GPS electron flux data, and tested on more than 1:5 years of measurements. 10‐fold cross validation yields that the model predicts the MEO radiation environment well, both in terms of dynamics and amplitudes of flux. Evaluation on the test set yields high correlation between the predicted and observed electron flux (0.8) and low values of absolute error. The MERLIN model can have wide space weather applications, providing information for the scientific community in the form of radiation belts reconstructions, as well as industry for satellite mission design, nowcast of the MEO environment and surface charging analysis.

Description: We present global statistical models of both wave amplitude and wave normal angle (WNA) of plasmaspheric hiss using Van Allen Probe‐A observations. They utilize the time history of solar wind parameters, that is, interplanetary magnetic field B Z and solar wind speed, and the AE index for each measurement of hiss waves as inputs. The solar wind parameter‐based model generally results in higher performance than using only the AE index as an input. Both observations and model results reveal a clear dependence of hiss wave distribution on the magnetic local time (MLT): Higher amplitudes with field‐aligned (〈30o) WNAs occur more frequently on the dayside than on the nightside. Such a tendency does not depend on magnetic latitude (MLAT), but slightly larger WNAs with a relatively low amplitude frequently appear for larger MLAT (〉10o). We also examine how significantly the electron loss rates in the slot region can be changed by incorporating the model output of hiss waves into a diffusive transport simulation. Simulation results show that during a typical timescale (roughly a couple of days) of a corotating interaction region‐driven storm, the nightside hiss waves with larger WNA (〉30o) do not contribute to the electron loss in the slot region due to their low amplitude and large WNA, while dayside hiss with WNAs less than 30o and comparatively higher amplitudes leads to a fast drop in flux, especially for electrons of a few hundred keV.

Description: The direction and strength of geomagnetic field had been evolving continuously in the past. One of the few means of obtaining continuous reconstructions of this evolution relies on sedimentary records. The latter are therefore important for understanding the geodynamo and the underlying evolution of the Earth’s interior, as well as providing an important dating tool through magnetostratigraphy. Sedimentary records of geomagnetic field variations rely on two main recording mechanisms: the alignment of magnetic particles, which underlies continuous records of relative paleointensity (RPI), and the archivation of cosmogenic isotopes, in particular ¹⁰Be, whose production by cosmic ray spallation is modulated by the screening action of the dipole component of the Earth’s field. Previous studies reported similarities as well as significant differences between RPI and cosmogenic ¹⁰Be (expressed as ¹⁰Be/⁹Be) records. While a perfect match of the two records is not expected due to environmental contaminations present in both records, the similar changes during the periods characterised by significant decrease of the dipole moment are suggested owning to global field strength control of ¹⁰Be production and attenuation of non-dipolar features in RPI records measured within the sediments with the low sedimentation rates (〈10 cm/ka). The aim of the present work was to improve our present knowledge on the field recording mechanisms of marine sediments, in particular: The environmental factors responsible for ¹⁰Be transport and removal from the water column, and the effect of source distributions on ⁹Be supply. The effect of post-depositional processes, in particular sediment mixing, on ¹⁰Be and RPI records. The mechanism by which a post-depositional magnetization is acquired near the bottom of the surface mixed layer. The causes of a systematic lag between ¹⁰Be and RPI records, and the environmental factors affecting RPI. In order to disentangle the environmental and magnetic contribution in sedimentary ¹⁰Be/9Be records, we analysed five records, covering the last geomagnetic reversal. Different recording characteristics at the five sites have been described in terms of additive and multiplicative climatic modulations, which depend essentially on water depth, location along large oceanic current systems, and distance to the coast. Simple criteria have been derived for the identification of most suited sites yielding minimal environmental contaminations. A new bioturbation model has been developed to explain sedimentary NRM in bioturbated sediment. This model includes a newly discovered phenomenon of size segregation in the surface mixed layer (SML), analogous to the well-known Brazil nut effect. Size segregation is responsible for the longer permanence of larger particles in the SML, up to the limit case of ferromanganese nodules and has important implications for sediment dating with benthic foraminifera. Calibration of the bioturbation model with microtektite profiles from two Indian Ocean cores enabled to reproduce the correct degree of delay between ¹⁰Be and RPI records, as well the environmental dependence of RPI in two cores from the North Atlantic and the Equatorial Pacific Oceans. The results obtained in this work can aid in developing integrated approaches for the correction of climatic contaminations in ¹⁰Be and RPI records. Furthermore, the predictive power of the bioturbation-based model for NRM acquisition can be used to design new laboratory experiments for the simulation of specific magnetic recording mechanisms. We have demonstrated the Brazilian-nut effect on the microtektite particles, that consists in size-dependent fragments segregation. The results of this research have significant importance not only for the sediment mixing response characterisation and reconstruction of affected by bioturbation processes records (e.g. ¹⁰Be /⁹Be),..

Description: A new model validation and performance assessment tool is introduced, the sliding thresholdof observation for numeric evaluation (STONE) curve. It is based on the relative operating characteristic(ROC) curve technique, but instead of sorting all observations in a categorical classification, the STONE tooluses the continuous nature of the observations. Rather than defining events in the observations and thensliding the threshold only in the classifier/model data set, the threshold is changed simultaneously for boththe observational and model values, with the same threshold value for both data and model. This is onlypossible if the observations are continuous and the model output is in the same units and scale as theobservations, that is, the model is trying to exactly reproduce the data. The STONE curve has severalsimilarities with the ROC curve—plotting probability of detection against probability of false detection,ranging from the (1,1) corner for low thresholds to the (0,0) corner for high thresholds, and values above thezero‐intercept unity‐slope line indicating better than random predictive ability. The main difference isthat the STONE curve can be nonmonotonic, doubling back in both thexandydirections. These ripplesreveal asymmetries in the data‐model value pairs. This new technique is applied to modeling output of acommon geomagnetic activity index as well as energetic electronfluxes in the Earth's innermagnetosphere. It is not limited to space physics applications but can be used for any scientificorengineeringfield where numerical models are used to reproduce observations.

Description: Using Poynting vector measurements of whistler mode chorus emissions detected by the THEMIS spacecraft within the source region, that is, close to the magnetic field minimum, we found both in individual events and statistically that chorus elements propagating equatorward had systematically higher frequencies and smaller amplitudes compared with simultaneously observed elements propagating away from the equator. We demonstrate similar features in the results of numerical simulations based on backward wave oscillator equations. It can be qualitatively explained by the nonlinear evolution of the energetic electron distribution function during wave generation. The motion of electrons from the equator is accompanied by a decrease in their velocity component along the magnetic field line due to both the adiabatic mirror force and nonlinear wave-particle interactions. Thus, the frequency of the chorus elements generated by such electrons and propagating equatorward is higher compared with the elements propagating away from the equator.

Description: The Afar region represents a unique opportunity for the study of ongoing rift development and the various phases of continental break-up. In this work we discuss the geological and geomorphological characteristics of the Western Afar Margin (WAM) and the various scenarios proposed for its evolution. A drastic decline in topography and crustal thickness from the Ethiopian Plateau into the Afar Depression, as well as a series of marginal grabens and a general presence of antithetic faulting characterize the WAM. Present-day extension is mostly accommodated at the rift axis in Afar, yet the margin is still undergoing significant deformation. Models for the evolution of the WAM involve either isostatic loading effects due to erosion, rifting-induced block rollover, large-scale detachment fault development or crustal flexure due to lithospheric stretching or magmatic loading. This wide variation of potential mechanisms for WAM development may reflect a general structural variation along the margin and in Afar, involving different stages of rift formation and possibly indicating two distinct pathways leading to continental break-up. In order to better understand the rifting mechanisms and to fully exploit the research potential of the region, further assessment of the WAM and its relation to Afar will be necessary. The findings of such future work, combined with data from rifts and passive margins from around the globe will be of great importance to assess the processes involved in continental breakup and to better constrain the sequence of events leading from initial rifting to break-up and oceanic spreading.

Description: The Afar region in East Africa represents a key location to study continental breakup. We present an integrated structural analysis of the Western Afar Margin (WAM) aiming to better understand rifted margin development and the role of plate rotation during rifting. New structural information from remote sensing, fieldwork, and earthquake data sets reveals that the N-S striking WAM is still actively deforming and is characterized by NNW-SSE normal faulting as well as a series of marginal grabens. Seismicity distribution analysis and the first-ever borehole-calibrated sections of this developing passive margin show recent slip concentrated along antithetic faults. Tectonic stress parameters derived from earthquake focal mechanisms reveal different extension directions along the WAM (82°N), in Afar (66°N) and in the Main Ethiopian Rift (108°N). Fault slip analysis along the WAM yields the same extension direction. Combined with GPS data, this shows that current tectonics in Afar is dominated by the local rotation of the Danakil Block, considered to have occurred since 11 Ma. Earlier stages of Afar development (since 31–25 Ma) were most likely related to the large-scale rotation of the Arabian plate. Various authors have proposed scenarios for the evolution of the WAM. Any complete model should consider, among other factors, the multiphase tectonic history and antithetic fault activity of the margin. The findings of this study are not only relevant for a better understanding of the WAM but also provide insights into the role of multiphase rotational extension during rifting and passive margin formation in general.

Description: The Afar region in East Africa is a key locality for studying continental break-up. Within Afar, passive margins are developing, of which the Southern Afar Margin (SAM) contains synthetic (basinward) faulting, whereas crustal flexure, antithetic faulting and marginal grabens occur along the Western Afar Margin (WAM). Numerous conflicting scenarios for the evolution of the WAM exist. In this analogue modelling study we test various factors that may affect the development of a WAM-style passive margin: brittle crustal thickness, (en echelon) rheological contrasts, sedimentation and oblique extension. Our experimental results illustrate how marginal flexure due to a weak lower crust below Afar can elegantly account for the structural features of the WAM. Brittle crustal thickness controls what structures occur: a thinner brittle crust accommodates flexure internally, whereas increasing brittle thicknesses lead to faulting. Large escarpment faults develop early on, followed by late-stage antithetic faulting and marginal grabens. A thicker brittle crust also causes enhanced subsidence, and increased strength contrasts between lower crustal domains leads to more localized deformation. Basin-wide sedimentation causes enhanced subsidence, as well as longer activity along large synthetic (escarpment) faults. Finally, oblique extension clearly prevents the development of marginal grabens, which only form in near-orthogonal extension. These results support a tectonic scenario involving initial oblique extension due to Arabian plate motion, creating echelon synthetic escarpment faults along the WAM. After the Danakil Block started its independent rotation, near-orthogonal extension conditions were established, allowing (enhanced) marginal flexure, antithetic faulting and marginal graben formation along the older en echelon escarpment. Differences in extension obliquity may also explain the differences in structural architectures between the WAM and SAM. The characteristics of the WAM are typical of magma-rich passive margins, and the margin has great potential for studying continental break-up and (magma-rich) passive margin formation.

Description: In rift settings, extension rates often vary along strike, due to rotation about a vertical axis or Euler pole, yet tectonic modelers traditionally apply constant along-strike deformation rates. Here we compare rift development and propagation under traditional orthogonal extension versus rotational extension conditions. The set-ups involve brittle-viscous layering and localize deformation through structural weaknesses (seeds). Our models provide first-order insights into the differences in rift development between both boundary conditions: orthogonal extension produces a rift basin with constant synchronous along-strike features, whereas rotational extension induces along-strike structural gradients, diachronous rift development causing rift propagation and the development of V-shaped basins. We observe important viscous flow associated with differential pressure gradients in rotational extension. We also describe the important effects of strain partitioning between rift axis and model boundaries, the quantifying of which is crucial to avoid incorrect model interpretations. Although our model results are first-order only, they are in good agreement with various natural examples and previous modeling studies and highlight the importance of considering the third dimension when studying tectonic systems.

Description: During extension of the continental lithosphere, rift basins develop. These are often initially offset, and must interact and connect in order to create a continuous rift system that may ultimately achieve break-up. When simulating extensional tectonics and rift interaction structures, analogue and numerical modellers often apply a continuous extension rate along the strike of a rift or rift system. Yet in nature significant extension velocity variations occur along rifts and plate boundaries as a natural consequence of tectonic plates moving apart about a pole of rotation, resulting in rotational extension, and associated rift propagation and structural gradients. Here we present various analogue tectonic experiments to assess rift interaction structures forming in orthogonal extension settings versus rotational extension settings. Our modelling efforts show that rotational extension and orthogonal extension produce significantly different large-scale structures. Rotational extension can cause important variations in rift maturity between rift segments, delay rift interaction zone development, and make rift segments propagate in opposite directions. Still, local features in a rotational extension system can often be regarded as evolving in an orthogonal extension setting. Furthermore, we find that various degrees of rift underlap produce three basic modes of rift linkage structures. Low underlap distance (high angle φ) experiments develop rift pass structures. With increasing underlap distance (φ = ca. 40°), transfer zone basins develop. High degrees of underlap (φ ≤ 30°) tend to result in en echelon sub-basins. Our results match with data from previous modelling efforts and natural examples. We furthermore propose a large-scale tectonic scenario for the East African Rift System based on rotational extension and associated rift propagation. These insights may also be applicable when studying other large-scale rift systems.

Description: Recent years have seen debate regarding the ability of electromagnetic ion cyclotron (EMIC) waves to drive EEP (energetic electron precipitation) into the Earth's atmosphere. Questions still remain regarding the energies and rates at which these waves are able to interact with electrons. Many studies have attempted to characterize these interactions using simulations; however, these are limited by a lack of precise information regarding the spatial scale size of EMIC activity regions. In this study we examine a fortuitous simultaneous observation of EMIC wave activity by the RBSP-B and Arase satellites in conjunction with ground-based observations of EEP by a subionospheric VLF network. We describe a simple method for determining the longitudinal extent of the EMIC source region based on these observations, calculating a width of 0.75 hr MLT and a drift rate of 0.67 MLT/hr. We describe how this may be applied to other similar EMIC wave events.

Description: We performed new high-resolution magnetic measurements of sedimentary cores from the east northern Pacific ODP Site 1021 and the East equatorial Pacific ODP Site 851. ODP Site 1021 is characterized by a high clay content with less than 10% carbonates in contrast to ODP Site 851 which is highly carbonated (% CaCO3 of at least 70%). The time scale of both records was obtained by orbital tuning of sediment density and/or susceptibility variations and whenever possible tested against the reversal positions. Previous magnetic studies at both sites have been concentrated on the past 1.2 Ma using U-channels. We extended this period and performed high resolution and detailed studies of 4210 sediment levels that cover the past 4.4 Ma. Natural remanent magnetization (NRM) and anhysteretic remanent magnetization (ARM) were both stepwise demagnetized by alternating fields. The new results confirm the magnetostratigraphy derived from the shipboard measurements but improve the definition of the polarity intervals and identify zones or events that were either unclear or hidden by unremoved secondary components. Studies of relative paleointensity were conducted following the standard rules and yielded determinations with the exception of intervals that were either too weakly magnetized or disturbed. The evolution of relative paleointensity displays similar behavior during the reversal periods at both sites, but the two curves show strikingly different patterns outside the transitional intervals that are characterized by the largest intensity changes. Spectral analyses revealed that magnetic concentration was strongly dependent on paleoenvironmental components at ODP Site 1021 which likely affected the results of relative paleointensity. It is assumed that the absence of any long-term geomagnetic trend during the stable polarity intervals at this site results from the interplay between climatic and geomagnetic factors. The large amplitude of field intensity decrease during the reversal periods dominates all other factors and is thus visible over the entire record.

Description: This interactive webpage contains supplementary information for the publication by Jamalreyhani et al., 2020: Seismicity related to the eastern sector of Anatolian escape tectonics: A seismic gap partly filled by the 24 January 2020 Mw 6.8 Elazığ-Sivrice earthquake.

Description: The Lake Junín Drilling Project, co-funded by the International Continental Scientific Drilling Program, ICDP, aims to provide a continuous paleoclimate record from lacustrine sediments, and to reconstruct the history of the continental records covering the glacial-interglacial cycles spanning more than 500 kyr. Lake Junín, also known as Chinchaycocha, is a shallow (maximum water depth of 12 m), inter-mountain high-elevation (at 4100 m a.s.l.) lake in the inner-tropics of the Southern Hemisphere that spans 300 km2 in the tropical Andes of Peru. Drill cores were recovered during summer 2015 from three drill sites on the lake. After the completion of coring operations in each hole, downhole logging measurements were performed in five of the 11 boreholes (1A, 1C, 1D, 2A and 3B) by the Operational Support Group of ICDP at GFZ Potsdam (OSG). The OSG logging data from Lake Junín Drilling Project is given here in three data formats. For each of the five boreholes all processed logging data are comprised in one composite logging data set, this set is given here both in ASCII text and in WellCAD format. Additionally, the raw sonic waveform data are in LIS format: • Composite logging data in ASCII text files (.txt) • Composite logging data in WellCAD format (.wcl) • Sonic raw data (waveforms) in LIS format (.lis) Detailed description is provided in the associated data description file.

Description: Reductive transformation of organic contaminants by FeS in anoxic environments has been documented previously, whereas the transformation in oxic environments remains poorly understood. Here we show that phenol can be efficiently oxidized in oxic FeS suspension at circumneutral pH value. We found that hydroxyl radicals (•OH) were the predominant reactive oxidant and that a higher O2 content accelerated phenol degradation. Phenol oxidation depended on •OH production and utilization efficiency, i.e., phenol degraded per •OH produced. Low FeS contents (≤1 g/L) produced less •OH but higher utilization efficiency, while high contents produced more •OH but lower utilization efficiency. Consequently, the most favorable conditions for phenol oxidation occurred during the long-term interaction between dissolved O2 and low levels of FeS (i.e., ≤1 g/L). Mössbauer spectroscopy suggests that FeS oxidation to lepidocrocite initially produced an intermediate Fe(II) phase that could be explained by the apparent preferential oxidation of structural S(−II) relative to Fe(II), rendering a higher initial •OH yield upon unit of Fe(II) oxidation. Trichloroethylene can be also oxidized under similar conditions. Our results demonstrate that oxidative degradation of organic contaminants during the oxygenation of FeS can be a significant but currently underestimated pathway in both natural and engineered systems.

Description: We conducted brittle-viscous analogue models to test the influence of pre-existing fault-steps on the evolution of structures in a viscous layer overlain by a brittle layer of granular material. The brittle layer is pushed horizontally (from right to left in videos and CT cross-sections). The viscous layer is ca. 13 mm thick and is made of a mixture of Polydimethylsiloxane (PDMS) and corundum sand that has a density of ca. 1600 kg/m^3 (Zwaan et al., 2018). The brittle layer has a thickness of 70 mm (except in model U20-45-RC, where the thickness is 40 mm) and consists of quartz sand that has a bulk density of 1560 kg/m^3 (Klinkmüller et al., 2016). Analogue models test oblique and frontal fault-steps and represent the case of the Jura Mountains fold-and-thrust belt (JFTB) in the Northern Alpine Foreland, where pre-existing faults in the pre-Mesozoic basement are suspected to have localised and controlled deformation during JFTB evolution (Laubscher 1961). The viscous layer at the base simulates a décollement zone made of Trassic evaporites (salt and anhydrite), whereas the brittle quartz layer simulates the Mesozoic carbonate cover (limestone, dolomite, marl) of the JFTB. This supplementary material contains top-view videos of brittle-viscous analogue model experiments, which feature flat-base, frontal and oblique steps. Thick, black lines across models indicate the position of the vertical base-plate step (absent in flat-base models F1 and F2). Thin black lines to the left and right of the step indicate the calculated position of thrusts at the surface, which nucleate above the step (step-controlled thrusts). The dip angle of thrust planes, used to calculate the position of step-controlled thrust lines, is given in the parameter list at the bottom left of each video. The parameters specify (1) the throw of the base-plate step and the obliquity angle α of the oblique step in respect to frontal steps (α = 0°). (2) Scaling ratio of the image in pixels per centimetres. (3) The dip, which was used to construct the surface line of step-controlled fore-thrusts (thin, black line across the model to the left of the thick black line). Step-controlled thrusts are presumed to nucleate above the upper step-edge. (4) The dip assumed to construct the backthrust line across the model (thin, black line to the right of the thick black line). (5) Velocity of backstop displacement. (6) Thickness of the brittle cover. (7) Thickness of the viscous base layer with comments in uneven distributions. In addition to top-view videos, this supplementary material also comprises a PDF file with five cross-sections across model U20-45°-CT, which features an oblique upward step with a throw of 20 mm and an obliquity angle of 45°. Cross-sections are raw slices across computed tomography (CT) scans of model U20-45°-CT. CT-scans were conducted in 15 minute intervals.

Description: This dataset provides rheometric data of three viscous materials used for centrifuge experiments at the Tectonic Modelling Laboratory of CNR-IGG at the Earth Sciences Department of the University of Florence (Italy). The first material, PP45, is a mixture of a silicone (Polydimethylsiloxane or PDMS SGM36) and plasticine (Giotto Pongo). The PDMS is produced by Dow Corning and its characteristics are described by e.g. Rudolf et al. 2016a,b). Giotto Pongo is produced by FILA (Italy). Both components are mixed following a weight ratio of 100:45, and the final mixture has a density of 1520 kg m3. The second material, SCA705 is a mixture of Dow Corning 3179 putty, mixed with fine corundum sand and oleic acid with a weight ratio of 100:70:05 and a resulting density of 1660 kg m3. The final material, SCA7020 consists of the same components as SCA705, but with a slightly higher oleic acid content reflected in the weight ratio of 100:70:20. The mixture’s density is 1620 kg m3. The material samples have been analyzed in the Helmholtz Laboratory for Tectonic Modelling (HelTec) at GFZ German Research Centre for Geosciences in Potsdam using an Anton Paar Physica MCR 301 rheometer in a plate-plate configuration at room temperature (20˚C). Rotational (controlled shear rate) tests with shear rates varying from 10-4 to 1 s-1 were performed. Additional temperature tests were run with shear rates between 10-2 to 10-1 s-1 for a temperature range between 15 and 30˚C. According to our rheometric analysis, the materials all exhibit shear thinning behavior, with high power law exponents (n-number) for strain rates below 10-2s-1, while power law exponents are lower above that threshold.For PP45, the respective n-numbers are 4.8 and 2.6, for SCA705 6.7 and 1.5, and for SCA7020 9.1 and 2.0. The temperature tests show decreasing viscosities with increasing temperatures with rates of -3.8, -1.4 and -1.9% per ˚K for PP45, SCA705 and SCA7020, respectively. An application of the materials tested can be found in Zwaan et al. (2020).

Description: This data set includes videos depicting the surface evolution of 29 analogue models on crustal extension, as well as 4D CT imagery (figures and videos) of two of these experiments. The experiments examined the influence of the method for driving extension (orthogonal or rotational) on the interaction between rift segments using a brittle-viscous set-up. All experiments were performed at the Tectonic Modelling Laboratory of the University of Bern, Bern, Switzerland (UB). Brittle and viscous layers are both 4 cm thick, extension velocities are 8 mm/h so that a model duration of 5 h yields a total extension of 40 mm (e = ca. 13%, given an initial model width of ca. 30 mm). Next to the mode of extension (orthogonal or rotational), we also test the effect of the degree of onderlap (angle φ). Detailed descriptions of the experiments and monitoring techniques can be found in Zwaan et al. (2020).

Description: This data set includes the results of digital image correlation of ten brittle-viscous experiments on crustal extension and four benchmark experiments performed at the Tectonic Modelling Lab of the University of Bern (UB). The experiments demonstrate the differences in rift development in orthogonal versus rotation extension. Detailed descriptions of the experiments and monitoring techniques can be found in Zwaan et al. (2019) to which this data set is supplementary. Additional background information concerning the general modelling approach are available in Zwaan et al. (2016).. The data presented here consist of movies displaying digital image correlation (DIC) derived surface and internal displacement fields as well as profiles of the lateral cumulative surface displacements. Digital photographs of the experimental surface and digital image cross section of the computed CT-scans were analyzed with DIC (Adam et al., 2005, 2013) techniques to quantify displacements in the image plane at high precision (〈0.1 mm). DIC was undertaken with the software DaVis 8.0 (LaVision) applying 2D-DIC (FFT-legacy) multipass processing with a final interrogation window size of 32x32 (CT: 12x12) pixels and 50% (CT: 25%) overlap.

Description: This dataset provides internal data from ring-shear tests (RST) on a feldspar sand material that has been used in tectonic experiments by among others Montanari et al. (2017) and Zwaan et al. (2020) in the Tectonic Modelling Laboratory of CNR-IGG at the Earth Sciences Department of the University of Florence (Italy) as an analogue for brittle layers in the crust. The material has been characterized by means of internal friction coefficients μ and cohesions C as a remote service by the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam for the Tectonic Modelling Laboratory of CNR-IGG at the Earth Sciences Department of the University of Florence (CNR-UF) According to our analysis the material behaves as a Mohr-Coulomb material characterized by a linear failure envelope. Internal peak, dynamic and reactivation friction coefficients are μP= 0.72, μD= 0.67, and μR= 0.72 respectively. Internal cohesions C are in the range of 60 to 120 Pa. Note however that these values differ from those reported by Montanari et al. (2017), who used empirical methods to determine material properties and find a friction angle of ca. 57˚ (i.e. a friction coefficient of ca. 1.5).

Description: This data set includes images and videos depicting the evolution of deformation and topography in 17 analogue experiments of passive margin development, to better understand the ongoing tec-tonics along the western margin of Afar, East Africa. The tectonic background that forms the basis for the experimental design is described in Zwaan et al. 2020a-d, and references therein. The ex-periments, in an enhanced gravity field in a large-capacity centrifuge, examined the influence of brittle layer thickness, strength contrast, syn-rift sedimentation and oblique extension on a brittle-viscous system with a strong and weak viscous domain. All experiments were performed at the Tectonic Modelling Laboratory of the Istituto di Geoscience e Georisorse - Consiglio Nazionale delle Ricerche (CNR-IGG) and of the Earth Sciences Department of the University of Florence (CNR/UF). The brittle layer (sand) thickness ranged between 6 and 20 mm, the underlying viscous layer, split in a competent and weak domain (both viscous mixtures), was always 10 mm thick. Asymmetric extension was achieved by removing a 1.5 mm thick spacer at the side of the model at every time step, allowing the analogue materials to spread when en-hanced gravity was applied during a centrifuge run. Differential stretching of the viscous material creates flexure and faulting in the overlying brittle layer. Total extension amounted to 10.5 mm over 7 intervals for Series 1 models that aimed at un-derstanding generic passive margin development in a generic orthogonal extension setting, where-as up to 16.5 mm of extension was applied for the additional Series 2 models aiming to reproduce the tectonic phases in Afar. In models involving sedimentation, sand was filled in at time steps 2, 4 and 6 (i.e. after 3, 6 and 9 mm of extension). Detailed descriptions of the experiments, monitoring techniques and tectonic interpretation of the model results are presented in Zwaan et al. (2020a).

Description: The origins of hydrocarbons occurring in oil-bearing fluid inclusions (FIs) have been studied in detail over the last four decades, but very little is known about co-occurring nitrogen, sulfur and oxygen (NSO)-containing compounds. Here, we outline a new method for gathering valuable information on NSO-compounds using the Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometry (FT-ICR-MS) in combination with Atmospheric Pressure Photoionization in positive ion mode (APPI (+)) and Electrospray Ionization in negative ion mode (ESI (−)). A key element was to develop a rigorous acid-free cleaning protocol to make oil inclusions from a broad range of host materials accessible to the very sensitive FT-ICR-MS technique. Although oil contamination from surrounding organic matter could not be entirely eliminated, the procedure enables distinction of external contaminants and identification of affected NSO-compound classes allowing a conditional interpretation of the FT-results of FI samples, especially for compounds measured in the APPI (+) mode. First insights into the high molecular weight hydrocarbons and NSO-compounds in FI oils are presented here using examples from Germany, Tunisia, Pakistan and Mexico.

Description: Volcanic eruptions are regularly observed on the island of Fogo, Cape Verde, with an average re-occurrence interval of ca. 20 years. However, the structure and extent of the related volcanic plumbing system are not well understood. Previous studies have investigated earthquakes related to magmatic processes connected with the Fogo volcano using conventional network configurations. Seismicity has been reported to occur mainly southwest of the island of Brava while a more recent study reports on activity focussed between Brava and Fogo. Multi-array seismology has the potential to significantly reduce the localization errors of seismic events in particular for those outside a station network and to lower the detection threshold. The subject of this study is the investigation of the local volcano-related seismicity applying multi-array methods which is a unique task amongst the research activities at German universities. The scientific aims are (a) to precisely map local events to constrain the structure of and the dynamic processes within the volcanic plumbing system, (b) to image the magma source region below the Fogo volcano using reflected and backscattered waves, and (c) to localize low-frequency volcanic tremor events. Waveform data are available from the GEOFON data centre, under network code 9J, and are embargoed until February 2022.

Description: Motivation: Several recent studies showed that the application of deep neural networks advanced the state-of-the-art in named entity recognition (NER), including biomedical NER. However, the impact on performance and the robustness of improvements crucially depends on the availability of sufficiently large training corpora, which is a problem in the biomedical domain with its often rather small gold standard corpora. Results: We evaluate different methods for alleviating the data sparsity problem by pretraining a deep neural network (LSTM-CRF), followed by a rather short fine-tuning phase focusing on a particular corpus. Experiments were performed using 34 different corpora covering five different biomedical entity types, yielding an average increase in F1-score of ∼2 pp compared to learning without pretraining. We experimented both with supervised and semi-supervised pretraining, leading to interesting insights into the precision/recall trade-off. Based on our results, we created the stand-alone NER tool HUNER incorporating fully trained models for five entity types. On the independent CRAFT corpus, which was not used for creating HUNER, it outperforms the state-of-the-art tools GNormPlus and tmChem by 5 pp - 13 pp on the entity types chemicals, species, and genes. Availability: HUNER is freely available at https://hu-ner.github.io. HUNER comes in containers, making it easy to install and use, and it can be applied off-the-shelf to arbitrary texts. We also provide an integrated tool for obtaining and converting all 34 corpora used in our evaluation, including fixed training, development and test splits to enable fair comparisons in the future.

Description: Screaton et al. (2019, https://doi.org/10.1029/2019GC008603) examined the role of sedimentation, sea level, and bottom water temperature (BWT) changes due to glaciation as drivers for the downward migration of the base of gas hydrate stability and gas hydrate formation. International Ocean Discovery Program (IODP) Site U1517 in the Hikurangi margin was used as a case study because data at this site document a marked increase in chloride over a broad depth range, which was attributed to recent gas hydrate formation. In a comment on Screaton et al. (2019, https://doi.org/10.1029/2019GC008603), Sultan (2020, https://doi.org/10.1029/2019gc008846) used a linear thermal profile to argue that inferences and characterization of methane hydrate at IODP Site U1517 were incorrect because some occur below his estimated base of gas hydrate stability (BGHS). Based on this apparent discrepancy, Sultan (2020, https://doi.org/10.1029/2019gc008846) further stated that low‐chloride spikes may be unreliable indicators of methane hydrate occurrence. In this reply, we emphasize that unsteady‐state, and thus nonlinear, thermal profiles are likely in areas experiencing active sedimentation and bottom‐water temperature (BWT) changes. The resulting deviation from steady‐state temperature profile shifts the BGHS downward. In addition, sedimentation has the potential to bury methane hydrate more rapidly than it dissociates, helping to explain how methane hydrate could be observed below the BGHS. We also review the supporting evidence for gas‐hydrate occurrence at Site U1517 and the criteria used for Site U1517 site selection.

Description: Beryllium (Be) is known to be one of the most toxic elements but at the same time exerts a stimulating effect on plant growth. Despite this contradiction, little is known about the Be metabolism in living organisms, partially because of the low amounts present and because the analysis of Be in plants by ICP‐MS remains challenging. The challenges arise from the complex organic matrix, the low abundance of Be relative to the other plant essential elements, and the matrix effects resulting thereof in the plasma. To address these challenges, we developed and evaluated a new method for Be concentration analysis in plant material. Key is the quantitative separation of Be from the other matrix elements by cation‐exchange chromatography. The new method was verified by processing seven reference materials representing different plant matrices yielding a long‐term reproducibility of 16% (RSD). Applying the method, Be concentrations in tree, shrub, bush, and grass samples grown in non‐polluted ecosystems from four temperate forests and a tropical rainforest were measured. The Be concentrations in different plant organs range from 0.01 to 63 ng/g that suggest a natural baseline for Be concentrations of 52 ng/g (95 percentile of non‐woody tissue) that may serve as bioindicator for Be pollution in the environment. Comparison of Be concentrations in plants with the soil's biologically available fraction revealed that Be is discriminated from uptake into shoots and thus can be considered as non‐essential.

Description: The Teutonic Bore Camp, comprised of the Teutonic Bore, Jaguar and Bentley deposits, is one of the most significant volcanic-hosted massive sulphide (VHMS) camps in Western Australia. Despite being extensively studied, only recently there have been advances in the understanding of the mechanism that drove the formation of mineralisation. It has been recognized by recent studies that the volcanic-hosted deposits from the Teutonic Bore Camp represent replacement-type VHMS systems, with significant input of fluids and metals from a magmatic source. This paper tests the existing hypothesis that the nearby Penzance granite acted as the metals source and/or thermal engine driving the development of these ore deposits. New age constraints on the formation of the host volcanic sequence at the Bentley deposit and the crystallization of the Penzance granite allows for the construction of a 4D evolutionary model for the ore system. A new U-Pb SHRIMP monazite age of 2681.9 ± 4.5 Ma indicates that the Penzance granite post-dates the host stratigraphy at Bentley (ca. 2693 Ma) and is probably coeval with mineralisation. All zircons (Penzance, Bentley units I and III) have very similar ƐHf(i), with most values between −1 and + 6, slightly higher than the ƐHf(i) of zircons from other granites and volcanics within the Kurnalpi Terrain, and indicative of juvenile sources. The mean Th/U ratios are ~0.7 and ~0.6 for the Penzance and Bentley zircons, respectively. All zircons have similar Ce/Nd(CN) ratios. The chemical similarities between the zircons from the granite and the volcanic rocks at Bentley support a shared magmatic source between the Penzance and the Teutonic Bore Camp sequence. The Penzance granite is the likely source of heat, and potentially metals, which drove the VHMS mineralisation at the Teutonic Bore Camp.

Description: Due to its unique mineralogy in the Archaean Yilgarn Craton, the origin of the high-grade Nimbus Ag-Zn-(Au) deposit has been contentious for a number of years. Recent interpretations of the deposit as a shallow water and low temperature volcanic-hosted massive sulphide (VHMS) deposit with epithermal characteristics (i.e. a hybrid bimodal-felsic deposit), were based on detailed studies of its volcanology, mineralogy, hydrothermal alteration assemblages, geochemistry, multiple S isotopes and trace element content of sulphide. However, this model has been questioned in favour of a late, epithermal fault-hosted system. Effective greenfields exploration for similar deposits elsewhere requires a robust deposit model, and well understood timing of ore formation. We present a comprehensive multi-disciplinary study to further constrain the processes involved in the evolution of Nimbus and generate a 4D evolutionary model of the system. Host rock dacite formation is well constrained by SHRIMP U-Pb zircon geochronology to c. 2703 Ma. Re-Os ages for the first sulphide phase, gives an imprecise maximum age to the ore formation of 2682 ± 110 Ma. High precision Pb-isotope variations in ore-stage and late galenas track changes in the sulphides over time, complemented by new geochronology. The Pb-isotope data indicates that the polymetallic ore precipitation happened at the same time as the volcanism, with the second generation indicating minor, local remobilisation of Pb in late quartz-carbonate veins at c. 2630 Ma. 40Ar/39Ar dating of sericite-altered plagioclase from foliated dacite, and U-Pb SHRIMP dating of syn- to post-deformation monazites have yielded ages of ~2630 Ma. The late event at c. 2630 Ma is most likely related to widespread late low-Ca granite emplacement across the Eastern Goldfields. This study provides arguments that suggest that Nimbus is a syn-volcanic deposit. The ore timing is consistent with the model of replacement-type VHMS deposit, with the age of the main mineralisation similar to the age of the dacitic host-rocks at 2703 Ma. The late event modifies the pre-existing ore and overprints the previous ore-related alteration ages from the altered plagioclase. High precision, double spiked, Pb isotope constraints from late quartz-carbonate veins provides an opportunity to vector to hidden deposits.

Description: We would like to announce that the latest issue of the Acta Geologica Slovaca Journal (Volume 12, Issue 2) has already been released at 11th December 2020.

Description: We would like to announce that the latest issue of the Acta Geologica Slovaca Journal (Volume 13, Issue 1) has already been released at 30th June 2021.

Description: The Authors lay out Libra’s design concept, the problems it seeks to solve, and the potential implications of its successful launch on the redesign of the global tax system that is already in progress.〈div class="enclosure"〉〈/div〉

Description: The tax treatment of cryptocurrency forks presents unique challenges. This Article provides evidence that each issue complicates the determination of income realization, or basis apportionment. We compare three existing approaches for assets acquired without a purchase.〈div class="enclosure"〉〈/div〉

Description: The deglaciation history and Holocene environmental evolution of northern Wijdefjorden, Svalbard, are reconstructed using sediment cores and acoustic data (multibeam swath bathymetry and sub-bottom profiler data). Results reveal that the fjord mouth was deglaciated prior to 14.5±0.3 cal. ka BP and deglaciation occurred stepwise. Biomarker analyses show rapid variations in water temperature and sea ice cover during the deglaciation, and cold conditions during the Younger Dryas, followed by minimum sea ice cover throughout the Early Holocene, until c. 7 cal. ka BP. Most of the glaciers in Wijdefjorden had retreated onto land by c. 7.6±0.2 cal. ka BP. Subsequently, the sea-ice extent increased and remained high throughout the last part of the Holocene. We interpret a high Late Holocene sediment accumulation rate in the northernmost core to reflect increased sediment flux to the site from the outlet of the adjacent lake Femmilsjøen, related to glacier growth in the Femmilsjøen catchment area. Furthermore, increased sea ice cover, lower water temperatures and the re-occurrence of ice-rafted debris indicate increased local glacier activity and overall cooler conditions in Wijdefjorden after c. 0.5 cal. ka BP. We summarize our findings in a conceptual model for the depositional environment in northern Wijdefjorden from the Late Weichselian until present.

Description: Due to the intensive ozone research in recent decades, the processes that influence stratospheric ozone are well understood. The chemistry and transport model ATLAS was developed to simulate the chemistry and transport of stratospheric ozone globally. The chemical rate of change of ozone is calculated at each model point and time step of the model by solving a system of differential equations that requires 55 input parameters (chemical species, temperatures, ...). But the computational e!ort to solve this complex system of differential equations is very high, and with respect to the overall limited computation time, this prevents the inclusion of ozone chemistry into ESMs. This project proposes a data-driven machine learning approach to predict the rate of change of stratospheric ozone. To derive a data set from modelled data, ATLAS was run for several short model runs. The rate of change of ozone and 55 parameters were stored at each model point and time step. By observing the co-variances of the high-dimensional feature-space, a large data set with reduced dimensionality has been created. A supervised learning algorithm used this data set of input and output pairs to train a deep feed- forward neural network (NN). This involved the identification and optimisation of several hyperparameters and to find a well- functioning combination of depth (number of layers) and width (number of neurons per layer). In this way, the NN model capacity is optimised with respect to the data itself. To evaluate this approach, the results were compared with another data-driven approach called SWIFT. The SWIFT model employs a repro-modelling approach that uses polynomials to approximate the rate of change of ozone. The resulting NN model is not only capable of learning the context of an eleven-dimensional hyperplane, but also improves the RMSE by about one order of magnitude compared to SWIFT’s previous polynomial approach. In addition, the deviations of the predictions at the boundaries (altitude and latitude) are significantly lower, which is a challenge for the polynomial approach. Only fully coupled ozone climate set ups are able to consider the complex interactions of the stratospheric ozone layer and climate. This is a step towards a computationally very fast but accurate application of an interactive ozone scheme in climate models.

Description: Major achievements The feedback provided by potential users on their needs was very much appreciated. They underlined the importance of having: ● an easy to deploy instrument (i.e.: from small fishing boats); ● multi-parameter sensors in ONE device; ● less maintenance effort and prioritized the variables to measure. Although, there are technical limitations and different solutions and there is no one tool that can do everything, which is low cost, has high resolution and low maintenance, the outcomes of the platforms/sensors/communications working group meet the main requirements that emerged. Priority was given to: ● a platform that will operate in drifter mode which is extremely easy to deploy and perfect for studies associated with search and rescue operations (another need that has emerged). It also constantly guarantees the knowledge of the instrument position. The platform can be easily converted into the moored mode. ● temperature and pressure sensors. The sensors will be low -cost with the idea to replace them rather than calibrate them; ● LoRaWAN communications preferably with Bluetooth integration for the in-situ download of the data.