The new critical metals database “HTMET”: High tech trace element characteristics of sulphides from base metal provinces in the variscan basement and adjacent sedimentary rocks in Germany

High tech (HT) trace elements such as germanium, gallium and indium gain rising importance in the development of innovative technologies. The database “HTMET” forms the first nationwide metal-ore database for Germany, created to visualise HT metal characteristics of base metal ores from important mining districts. Mineralogical and geochemical investigations on 478 samples and ore concentrates from 109 Pb-Zn-Cu occurrences were carried out using analytical methods with high spatial resolution and bulk sample methods. The database provides aggregated data based on 17,000 geochemical data sets, compiled information on regional infrastructure and environmental risks as well as data on innovative raw material-efficient processing techniques. Evaluation of combined data provides interactive maps revealing new potentials for specific HT metals in Germany. Differences in regional distribution of these trace elements and dependency of their concentration levels in the ore on the genetic deposit type became apparent. Sphalerite from the sediment-hosted massive sulphide (SHMS) deposit “Rammelsberg” and skarn deposits in the Erzgebirge contain elevated indium contents (median 14–119 ppm), whereas the SHMS deposit “Meggen” is poor in HT metals. Germanium forms the predominant HT trace element in colloform sphalerite of Mississippi-Valley-Type (MVT) deposits (median 29–147 ppm); in contrast, crystalline sphalerite is low in germanium in this deposit type. Sphalerite in all hydrothermal vein deposits shares a distinct enrichment in gallium (median 6–81 ppm); however, germanium and indium concentrations vary significantly depending on the metal source and fluid conditions. The Ruhrgebiet and the Schwarzwald ore veins show an enrichment in germanium (median 55–73 ppm), whilst vein sphalerite from the Erzgebirge is specialised in indium (median 33 ppm). The data demonstrate that the HT trace element inventory of the studied base metal sulphides is not only a function of the genetic ore deposit type, but is also triggered by locally variable geology such as source rock and fluid composition and organic content of the rock. Gallium seems to derive from adjacent lithologies, whereas indium and germanium may have more distant sources

The Preservation of Cellulose in Fossil Wood – Implications from Organic Geochemical Study of Fossil and Modern Wood

Fossil wood with well-preserved cellulose is detected in open-cast mines of the Miocene Lusatia lignite-mining district (eastern Germany). Aimed to explain the preservation of cellulose, an organic geochemical study was performed on the fossil wood samples and intact heartwood tissues of the respective modern woody species. The results of micro Fourier transform infrared (micro-FTIR) spectroscopy, biomarker distributions and δ13C values indicate that the preservation of cellulose in fossil wood samples was governed by reducing conditions. Furthermore, it can be also attributed to weathering of the surrounding tuff- and rhyolite-dominated acidic volcanic rock that might have caused lowering of pH. All fossil wood samples contain minor hopanoids, implying negligible post-depositional microbial degradation of OM. Limited microbial degradation of OM could be also caused by protection of the wood by conifer resins. For example, fossil Cupressaceae sensu lato, as confirmed by detection of hibaene, totarane, and cuparene, was more resinous than the modern forms. The absence of perylene in fossil wood indicates the limited degradation of wood by fungi

Overview of the MOSAiC expedition: Physical oceanography

Arctic Ocean properties and processes are highly relevant to the regional and global coupled climate system, yet still scarcely observed, especially in winter. Team OCEAN conducted a full year of physical oceanography observations as part of the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC), a drift with the Arctic sea ice from October 2019 to September 2020. An international team designed and implemented the program to characterize the Arctic Ocean system in unprecedented detail, from the seafloor to the air-sea ice-ocean interface, from sub-mesoscales to pan-Arctic. The oceanographic measurements were coordinated with the other teams to explore the ocean physics and linkages to the climate and ecosystem. This paper introduces the major components of the physical oceanography program and complements the other team overviews of the MOSAiC observational program. Team OCEAN’s sampling strategy was designed around hydrographic ship-, ice- and autonomous platform-based measurements to improve the understanding of regional circulation and mixing processes. Measurements were carried out both routinely, with a regular schedule, and in response to storms or opening leads. Here we present alongdrift time series of hydrographic properties, allowing insights into the seasonal and regional evolution of the water column from winter in the Laptev Sea to early summer in Fram Strait: freshening of the surface, deepening of the mixed layer, increase in temperature and salinity of the Atlantic Water. We also highlight the presence of Canada Basin deep water intrusions and a surface meltwater layer in leads. MOSAiC most likely was the most comprehensive program ever conducted over the ice-covered Arctic Ocean. While data analysis and interpretation are ongoing, the acquired datasets will support a wide range of physical oceanography and multi-disciplinary research. They will provide a significant foundation for assessing and advancing modeling capabilities in the Arctic Ocean

The impact of cemented layers and hardpans on oxygen diffusivity in mining waste heaps: a field study of the Halsbrücke lead–zinc mine tailings (Germany)

This article reports fibre-optic oxygen measurements on a reactive mine waste heap located in the polymetallic sulphide mine district of Freiberg in south-eastern Germany. The heaped material consists of sulphide-bearing tailings from a processing plant of a lead–zinc mine. Mine waste material was deposited in the water phase after separation of mining ores in a flotation process. The tailing impoundment is partly covered with coarse sand and topsoil. Oxygen profiles were monitored during one year at eleven locations showing different physical and mineralogical compositions. At each location a borehole was drilled where the optic sensors were installed at 2–5 different depths. After installation the oxygen profiles were monitored seven times during one year from 2006–2007 and three to five oxygen profiles at each location were obtained. Oxygen measurements were accompanied by physical, chemical and mineralogical data of the tailing material. Additionally, a detailed mineralogical profile was analysed at a location representative for the central part of the heap, where the cemented layers show lateral continuity. Results showed that cemented layers have a significant influence on natural attenuation of the toxic As and Pb species owing to their capacity of water retention. The measured oxygen profiles are controlled by the zone of active pyrite weathering as well as by the higher water content in the cemented layers which reduces gaseous atmospheric oxygen supply. In contrast, gypsum bearing hardpans detected at three other locations have no detectable influence on oxygen profiles. Furthermore, the grain size distribution was proved to have a major effect on oxygen diffusivity due to its control on the water saturation. Temporal changes of the oxygen profiles were only observed at locations with coarse sediment material indicating also an important advective part of gas fluxUnidad de Sevilla, Instituto Geológico y Minero de España, EspañaBundesanstalt für Geowissenschaften und Rohstoffe, AlemaniaFachbereich Geowissenschaften, Freie Universität Berlin, Alemani

The impact of hardpans and cemented layers on oxygen diffusivity in mining waste heaps: diffusion experiments and modelling studies

This study reports column tests and modelling results to assess the impact of hardpands and cemented layers on oxygen supply in mine waste sediments. The analysed sediment samples were obtained from a low-sulphide and low-carbonate polymetallic mine waste tailings impoundment located in the Freiberg mining district in Germany. The three samples were characterised by different degrees and types of cementation. After physical and mineralogical properties of the samples had been determined, breakthrough curves of oxygen were measured in column studies at different degrees of water saturation, and the diffusivities were assessed using a numerical modelling approach. Results demonstrate that cemented layers and hardpans in undisturbed sediments associated with fine-grained material operate as preferential pathways for diffusive gas transport during rewetting, leading to higher oxygen diffusivities compared to disturbed sediments. Under air-dry conditions, the disturbed samples show higher diffusivities than the undisturbed sample, indicating clogging of the porosity by precipitation of secondary minerals such as trivalent Fe oxyhydroxides acting as a barrier and thereby decreasing the diffusivity of the undisturbed sample. In contrast to sediments without cementation, diffusion experiments of sediments with cemented layers used in this study yield similar tortuosities in spite of their different grain size distributions, pointing to the important role of these heterogeneities for gas diffusion.Unidad de Sevilla, Instituto Geológico y Minero de España, EspañaBundesanstalt für Geowissenschaften und Rohstoffe, AlemaniaFachbereich Geowissenschaften, Freie Universität Berlin, Alemani

Enhanced chalcopyrite dissolution in stirred tank reactors by temperature increase during bioleaching

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Automatisierter Analog-Entwurf in Mikro- und Nanotechnologien: Tutorial

A huge effort was spent for the automation of analog IC design in the past decades - nevertheless, industries are still waiting for applicable solutions to solve recent problems such as increased efficiency during design phase, requirements on design safety and system reliability, especially for future more complex systems and mixed-signal designs in nanoscale technologies. the tutorial will present an approach of analog design automation (Intelligent Analg IP) with focus on achievements for microscale technologies, technology porting capabilities as well as challenges for future nanascale technologies below 28 nm. Industrial partners and design engineers will contribute to the tutorial to substantiate the demand on analog automation methodologies

The transition from porphyry- to epithermal-style gold mineralization at Ladolam, Lihir Island, Papua New Guinea: a reconnaissance study

The exceptionally large gold resource at Ladolam (>1,300 metric tons of gold), Lihir Island, resulted from the transition of an early-stage, low-grade porphyry gold system to a low-sulfidation epithermal gold event. This transition was probably triggered by rapid decompression during the partial slope failure of Luise stratovolcano and accompanied by the ingress of seawater. The original porphyry stage is indicated by remnant hydrothermal breccia clasts of strongly biotite–magnetite altered monzodiorite with disseminated pyrite ± chalcopyrite and poorly developed pyrite ± quartz stockwork veins. The breccias are overprinted by biotite–magnetite alteration and their matrix is strongly mineralized with disseminated auriferous pyrite. The breccias are cut by late-stage epithermal quartz–chalcedony–illite–adularia–pyrite veins and associated illite–adularia alteration that locally contain bonanza gold grades of up to 120 g/t. Isotope data suggest a magmatic source of sulfur in the gold-bearing fluids at Ladolam