Zechstein-Kupferschiefer Mineralization Reconsidered as a Product of Ultra-Deep Hydrothermal, Mud-Brine Volcanism

The Kupferschiefer is a copper-, polymetallic-, hydrocarbon-bearing black shale of the lowermost Zechstein Group of Permo-Triassic age (252 Ma) in Germany and Poland. It is usually 1 m thick and underlies 600,000 km2, extending from Great Britain to Belarus for a distance of over 1500 km. At a district scale, copper has been mined for over 800 years since its discovery circa 1200 A.D. Mineralogical, chemical, and geological analyses of the combined Zechstein-Kupferschiefer show strong chemical and paragenetic relationships between the Zechstein salines, Kupferschiefer, and Weissliegend sandstones that lead to a broader, more unified, genetically linked model related to deep-sourced, hot, hydrothermal, mud-brine volcanism. The overall Zechstein-Kupferschiefer chemical stratigraphy suggests density-/composition-driven fractionation of deep-sourced, metal-rich, alkali-rich, silica-aluminum-rich, halogen-rich, high-density brines. The ultimate brine source is interpreted to be serpentinized peridotite in the lower crust near the Moho transition to the mantle. Dehydration of the serpentinite source to talc (steatization) by mantle heat during failed, intra-continental rifting of the Pangaea supercontinent at the end of Permian time released vast amounts of element-laden, high-density brines into deep-basement fractures, depositing them into and above the Rotliegend Sandstone in the shallow Kupferschiefer Sea, which is analogous to the modern northern Caspian Sea

Regional lung aeration and ventilation during pressure support and biphasic positive airway pressure ventilation in experimental lung injury

INTRODUCTION: There is an increasing interest in biphasic positive airway pressure with spontaneous breathing (BIPAP+SBmean), which is a combination of time-cycled controlled breaths at two levels of continuous positive airway pressure (BIPAP+SBcontrolled) and non-assisted spontaneous breathing (BIPAP+SBspont), in the early phase of acute lung injury (ALI). However, pressure support ventilation (PSV) remains the most commonly used mode of assisted ventilation. To date, the effects of BIPAP+SBmean and PSV on regional lung aeration and ventilation during ALI are only poorly defined. METHODS: In 10 anesthetized juvenile pigs, ALI was induced by surfactant depletion. BIPAP+SBmean and PSV were performed in a random sequence (1 h each) at comparable mean airway pressures and minute volumes. Gas exchange, hemodynamics, and inspiratory effort were determined and dynamic computed tomography scans obtained. Aeration and ventilation were calculated in four zones along the ventral-dorsal axis at lung apex, hilum and base. RESULTS: Compared to PSV, BIPAP+SBmean resulted in: 1) lower mean tidal volume, comparable oxygenation and hemodynamics, and increased PaCO2 and inspiratory effort; 2) less nonaerated areas at end-expiration; 3) decreased tidal hyperaeration and re-aeration; 4) similar distributions of ventilation. During BIPAP+SBmean: i) BIPAP+SBspont had lower tidal volumes and higher rates than BIPAP+SBcontrolled; ii) BIPAP+SBspont and BIPAP+SBcontrolled had similar distributions of ventilation and aeration; iii) BIPAP+SBcontrolled resulted in increased tidal re-aeration and hyperareation, compared to PSV. BIPAP+SBspont showed an opposite pattern. CONCLUSIONS: In this model of ALI, the reduction of tidal re-aeration and hyperaeration during BIPAP+SBmean compared to PSV is not due to decreased nonaerated areas at end-expiration or different distribution of ventilation, but to lower tidal volumes during BIPAP+SBspont. The ratio between spontaneous to controlled breaths seems to play a pivotal role in reducing tidal re-aeration and hyperaeration during BIPAP+SBmean

Magnetic resonance imaging for quantitative assessment of lung aeration: A pilot translational study

Background: Computed tomography is the gold standard for lung aeration assessment, but exposure to ionizing radiation limits its application. We assessed the ability of magnetic resonance imaging (MRI) to detect changes in lung aeration in ex vivo isolated swine lung and the potential of translation of the findings to human MRI scans. Methods: We performed MRI scans in 11 isolated non-injured and injured swine lungs, as well as 6 patients both pre- and post-operatively. Images were obtained using a 1.5 T MRI scanner, with T1 - weighted volumetric interpolated breath-hold examination (VIBE) and T2 - weighted half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences. We scanned swine lungs, with reference samples of water and muscle, at different airway pressure levels: 0, 40, 10, 2 cmH2O. We investigated the relations between MRI signal intensity and both lung density and gas content fraction. We analyzed patients' images according to the findings of the ex vivo model. Results: In the ex vivo samples, the lung T1 - VIBE signal intensity normalized to water or muscle reference signal correlated with lung density (r2 = 0.98). Thresholds for poorly and non-aerated lung tissue, expressed as MRI intensity attenuation factor compared to the deflated lung, were estimated as 0.70 [95% CI: 0.65-0.74] and 0.28 [95% CI: 0.27-0.30], respectively. In patients, dorsal versus ventral regions had a higher MRI signal intensity both pre- and post-operatively (p = 0.031). Comparing post- versus pre-operative scans, lung volume decreased (p = 0.028), while the following increased: MRI signal intensity in ventral (p = 0.043) and dorsal (p < 0.0001) regions, and percentages of non-aerated (p = 0.028) and poorly aerated tissue volumes (p = 0.028). Conclusion: Magnetic resonance imaging signal intensity is a function of lung density, decreasing linearly with increasing gas content. Lung MRI might be useful for estimating lung aeration. Compared to CT, this technique is radiation-free but requires a longer acquisition time and has a lower spatial resolution

Point-of-Care Assessment of Direct Oral Anticoagulation in Acute Ischemic Stroke: Protocol for a Prospective Observational Diagnostic Accuracy Study

Background Treatment of ischemic stroke with recombinant tissue plasminogen activator for intravenous thrombolysis (IVT) must be delivered within a narrow time window after symptom onset. This effective hyperacute treatment can be administered after ruling out active anticoagulation with direct oral anticoagulants (DOACs). Whenever this is impractical, e.g., due to aphasia, plasmatic DOAC levels are measured with a consequent delay in the IVT decision-making process ranging from 30 to 60 minutes of time. This study will test the hypothesis that hyperacute point-of-care assessment of clotting time in the patient's whole blood has sufficient diagnostic accuracy to determine immediately whether stroke patients are pretreated with DOAC. Methods and Design This will be a prospective single-center diagnostic accuracy study in 1,850 consecutive acute ischemic stroke patients at a tertiary stroke center in Saxony, Germany. Presence of active anticoagulation with DOAC will be determined by point-of-care quantification of clotting time via whole blood viscoelastic testing (ClotPro) using Russell venom viper and ecarin assay compared with high-performance liquid chromatography-tandem mass spectrometry as the reference standard. Discussion Viscoelastic point-of-care assessment of clotting time in whole blood might improve swift delivery of time-sensitive hyperacute treatment with IVT in stroke patients

Zechstein Kupferschiefer in Spremberg und verwandten Standorten : heißer hydrothermaler Ursprung der polymetallischen Cu-Ag-Au-Lagerstätte

Copper-silver-gold-polymetallic (Cd, Hg, Mo, Co, Ni, Cr, V, Sb, U, Cs, Re, Pb, Zn, PGE) rich mineralization is present in the deposits containing Kupferschiefer black shale of the lowermost Zechstein Group of Late Permian (Lopingian) age in central Germany and southwestern Poland. Mineralized areas are near large shear lineaments at the border between the Saxo-Thuringian and Rheno-Hercynian zones. Polymetallic mineralization is contained in and geochemically transgresses the Upper Permian Rotliegend strata: the Weissliegend Sandstone, the Zechstein conglomerate, the Kupferschiefer sensu stricto, the Zechstein dolostone, and the overlying Werra carbonate rocks of the Zechstein Group. Hematitic alteration features of the Rote Fäule type are massively present. The mineralization occurs on a continental scale of more than 750 km in an east-westerly direction from eastern Poland to the Rhön near the Rhine valley in Germany in the so called European Copper Belt. The Spremberg-Graustein-Schleife Kupferschiefer deposit in the Lausitz of southeastern Germany has been newly explored and shows the high-grade metallic features of the typical Kupferschiefer deposits, e.g. in the Mansfeld area of Germany and the Lubin area of Poland. The deep drilling campaign from 2008 to 2010 produced much new sample material that became the basis for this scientific research undertaking, which is the first comprehensive study of its type in decades. The major focus of the study was to establish the nature and occurrence of the mineralization in its stratigraphic and ore depositional environment. The methodology employed was: (1) Geological mapping and sampling in the Spremberg-Graustein-Schleife deposit from the new drilling as well as from the drill repository of the LBGR Geological Survey of Brandenburg. This was also done in addition at the Rhön project, the Sangerhausen-Wettelrode deposit in Germany and the Konrad, Lubin, Polkowiecze-Sierosowiecze and Rudna deposits in Poland. (2) The SGS analytical services in Montreal, Canada, geochemically analyzed more than 800 rock powder samples of the exploration campaign 1956 to 1980 at Spremberg, as well as hundreds of new drill core assays were prepared from the new Spremberg exploration campaign. (3) Optical microscopy of more than 1,350 thin and polished rock sections were reviewed and the most important and significant ones were selected for detailed analysis. (4) Electron-microprobe (EMP) analytics, in which chemical compositions of minerals were determined. Textural relations were documented by back-scattered electron images. X-ray maps were produced to recognize the chemical zonation of minerals. 350 polished and thin sections from drill holes and underground locations were selected and analyzed. 626 measurements were taken of stoichiometric and non-stoichiometric metallic minerals, which resulted in new insights about their hot hydrothermal origin and depositional environment. Scanning electron microscope (SEM) studies with wavelength dispersive X-ray spectroscopy microprobe analyses (WDS) were conducted with the CAMECA SX 50. For the calculation of the mineral formulas and the mineral distribution diagrams, the Mincalc-5-program was used. (5) The Raman spectra were measured with the Horiba XpLora Raman microscope with confocal optics with laser wavelengths of 532 and 638 nm. The research focused on minerals and inclusions that were in the size fraction between 1 and 50 nm. Metallic minerals and hydrocarbon aggregates were identified and their intensity frequencies determined. (6) δ34S isotope analysis was conducted on 55 samples that were specifically selected to represent single sulfide aggregates to demonstrate the multi-phase nature of the mineralization. The mineral concentrates were analyzed with an EA-analyzer to SO2 at a reaction temperature of 1,050 °C. The S-isotopic composition was measured with a NC 2500 connected to a Thermo Quest Delta+XL mass spectrometer. The results confirmed the multi-phase nature of the deposit mineralization and supported the new model of origin. (7) Rock samples in historical and significant museum collections were reviewed and evaluated at the following places: Geological Collection at Universität Tübingen, Mansfeld Museum, Wettelrode Röhrigschacht Museum, German Federal Geological Survey Museum at Potsdam, Freiberg Bergakademie Mineralogical Museum, Polish Geological Museum, Warsaw, and Collection of the Mineralogical Institute of University Cracow, Poland. (8) Research progress was presented and discussed in-house and with national and international researchers at seminars, conferences and through publications. The new research results show that the high-grade, Upper Permian, Zechstein polymetallic deposits indicate strong chemical and paragenetic relationships that lead to a unified genetically linked model related to deep-sourced, hot hydrothermal, rift-related volcanism. Mantle heat during failed, intra-continental rifting of the Pangea supercontinent at the end of the Permian time released vast amounts of the exotic metal-rich, alkali-rich, silica-aluminum-rich, organic-rich, halogen-rich, high-density brines into deep-basement fractures, depositing them above the continental flysch Rotliegend sandstones and conglomerates. Detailed investigations show that the high-grade, exotic metal and hydrocarbon mineralization has a hot hydrothermal origin. These result in a micro-layered deposit that was extruded on the Upper Permian Rotliegend peneplain that may have been covered with a shallow Zechstein sea, which was very hostile to lifeforms, at the time of the Permian Mass Extinction. The mineral assemblies are unusual, often chemically non-stoichiometric and unique in their composition as they contain high-temperature and low-temperature minerals adjacent to each other. The stability fields of the sulfides indicate the temperature ranged between 72 °C and 557 °C and up to 1,120 °C for high digenite. Mineralogical results obtained through microscopy, microprobe, Raman spectroscopy, geochemistry and δ34S isotope analysis in this thesis show that: o The Kupferschiefer deposit type mineralization in its vast majority is somewhat monotonous, as it is made up in Spremberg and the European Copper Belt mainly of chalcocite (Cu2S), digenite (Cu1.75S5), covellite (CuS), bornite (Cu5FeS4), and chalcopyrite (CuFeS2), plus a high hydrocarbon content, which is significant as it occurs over a distance of more than 750 km in length. o Many of the copper minerals are of non-stoichiometric composition and unusual association. Bornite, chalcocite, chalcopyrite and pyrite occur as spherules, immiscible metallic drops in the slurry mud. Bornite of the Kupferschiefer sensu stricto T 1 layer often shows exsolutions of electrum (AuAg) and other solid state exsolutions with chalcopyrite and covellite, indicating pre-mixture in the rising metal-hydrocarbon mud slurry and rapid cooling after extrusion on the sea floor surface. o The microprobe element analysis of sulfide phases that are widespread in natural ores of the Kupferschiefer Cu-Ag deposits plot in a phase field that includes chalcocite, digenite, djurleiite, anilite, yarrowite (“blaubleibender” covellite), klockmannite, and krutaite. Klockmannite (CuSe) and krutaite (CuSe2) have a stability field of about 343 °C and 384 °C and thus document the high hydrothermal nature of the mineral deposition. o The δ34S sulfur stable isotopes are a unique feature to the Kupferschiefer sensu stricto and at Spremberg have a similar composition as those of the copper mineralization of the other deposits of the European Copper Belt. The δ34S sulfur stable isotopes are light to very light with values ranging from -31‰ to -40‰ (permille) in chalcocite-digenite and chalcopyrite samples of the lower Kupferschiefer sensu stricto. Given the high temperature of the sulfide mineralization, these low values cannot be explained by microbial reduction. As it is shown in published diagrams, deep-sourced systems of ultramafic to serpentinitic origin and composition can contribute brines with a similar δ34S sulfur stable isotope composition. o Geochemical major and trace element compositions are anomalous and are much enhanced compared to average global black shale. The Kupferschiefer sensu stricto analysis and geostatistical comparison diagrams demonstrate the interdependence of the base, precious and polymetallic mineralization with the hydrocarbon deposition in the Zechstein rocks. o Geometallurgical analysis of the available operational and scientific data proves the genetic association of the enriched ultrabasic-sourced elements PGE, Co, Ni, Cr, V, Se, Re, Os with the contemporaneously deposited hydrocarbons. o Geological observation and mineralogical analyses demonstrate that the hematitic “Rote Fäule” is a post Zechstein Kupferschiefer, pervasive alteration event. In places, the “Rote Fäule” may have two distinct phases, of which one might have added gold to the system, forming independent new deposits. The advancing “Rote Fäule” front creates a “TZ Transition Zone”, where existing base and precious metals are enriched to a higher grade. o The age of the Zechstein Kupferschiefer deposition is considered to be 252.5 M.y. This might vary slightly along the 750 km of the European Copper Belt. The age dating relies on illite and rhenium-osmium ages. Spremberg samples have been submitted to age dating. The mineralization has a multi-phase history with age dates spreading from 267.7 M.y. to the “Rote Fäule” alteration event date of 244.5 M.y. o Large, deep-reaching, continent-size rifting lineaments are known in the Zechstein mineralized area of the European Copper Belt. These NW-SE lineaments are disrupted by NE-SW faults. This tectonic pattern is common in all Kupferschiefer districts and has been demonstrated with a seismic exploration program at Spremberg. Geological observations and mapping in Sangerhausen-Wettelrode, Spremberg and the Lubin-Rudna district show that: o The Weissliegend sand is an injectite/extrudite, silica slurry of Zechstein age that mostly rests on top of the Permian Rotliegend peneplain and is covered in an undulating manner by Kupferschiefer sensu stricto. o The Weissliegend sands are cut by veins and veinlets of sulfides and hydrocarbon and Kupferschiefer-like black mud rock that may represent the feeder veins of an open, hot hydrothermal vent. o The Weissliegend sand hosts by far the majority in quality and quantity of the Kupferschiefer-type deposit mineable copper resources measured in 100s of million of tons. o These observations resulting in a high-temperature, hydrothermal emplacement model lead in their conclusion to a paradigm change that replaces the “obsolete” syn-sedimentary epigenetic model, with consequences: - future exploration and mine development, - can rely on parameters that are congruent with the scientific knowledge that in many aspects resembles Volcanic Submarine Massive Sulfide deposits, and - will assist in the finding and development of the so far termed(by the USGS) “undiscovered Kupferschiefer resources”. • The new model for the Zechstein Kupferschiefer deposits postulates a high-energy, hot-hydrothermal, extrusive environment not dissimilar to submarine “Black Smoker” and volcanogenic, submarine, metal-brine deposits. The metal-rich fluids ascended through deep-reaching faults and erupted as slurries in low-relief, mud volcanism above fractures in an open, shallow, inland sea. Metal sulfide deposition is systematically accompanied by the precipitation of silica, dolomitic carbonate, and illite, as well as primary copper chlorides, such as atacamite (CuCl2) and other brine minerals, such as anhydrite and sylvite. • The ultimate brine source is interpreted to be serpentinized peridotite in the lower crust near the Moho transition to the mantle. Dehydration of the serpentinite source to talc (steatization) by mantle heat during failed, intra-continental rifting of the Pangaea supercontinent at the end of Permian time released vast amounts of element-laden, high-density brines into deep basement fractures, depositing them above the continental flysch sediment Rotliegend sandstone and conglomerate peneplain in the shallow Kupferschiefer sea, which is analogous to the modern northern Caspian Sea and the Salton Sea of southern California, USA

Generation of Mud Volcanic Systems Sourced in Dehydrated Serpentospheric Mantle: A ‘Deep-to-Seep’ Model for the Zechstein Salines-Kupferschiefer Cu-Ag Deposits

Mud volcanism can provide a mechanism for hot hydrothermal muds and brines to ascend from dehydrated, serpentinized peridotite at the mantle-crust contact (Moho). Such mud volcanism may have occurred on a regional scale across northern Europe when high to low density brines erupted as metalliferous, hot, hydrothermal, hydrocarbon-rich mud slurries. These mud-brines were delivered to the Permo-Triassic unconformity in a shallow Zechstein sea during the Pangea breakup through a series of deep-seated conduits that connected the serpentosphere to the Zechstein unconformity. A three-stage, hot, hydrothermal, mud volcanic model can explain the Kupferschiefer-Zechstein-Rote Fäule sequence of polymetallic, hydrocarbon, and saline mineralization as a consequence of a three-stage, dehydration sequence of deep serpentospheric uppermost mantle. Dehydration products of mantle-heated serpentinite were produced in three sequential stages: (1) lizardite to antigorite, (2) antigorite to chlorite-harzburgite, and (3) chlorite-harzburgite to garnet peridotite. The dehydration of serpentine correlates to three stages of Zechstein-Kupferschiefer mineralization: (1) Weissliegend-Kupferschiefer Cu-Ag-carbonaceous shale and silica sand deposits, to (2) Zechstein saline deposits, to (3) Rote Fäule hematite-Au-REE-U cross-cutting metallization

Association of history of cerebrovascular disease with severity of COVID-19

OBJECTIVE To determine whether a history of cerebrovascular disease (CVD) increases risk of severe coronavirus disease 2019 (COVID-19). METHODS In a retrospective multicenter study, we retrieved individual data from in-patients treated March 1 to April 15, 2020 from COVID-19 registries of three hospitals in Saxony, Germany. We also performed a systematic review and meta-analysis following PRISMA recommendations using PubMed, EMBASE, Cochrane Library databases and bibliographies of identified papers (last search on April 11, 2020) and pooled data with those deriving from our multicenter study. Of 3762 records identified, 11 eligible observational studies of laboratory-confirmed COVID-19 patients were included in quantitative data synthesis. Risk ratios (RR) of severe COVID-19 according to history of CVD were pooled using DerSimonian and Laird random effects model. Between-study heterogeneity was assessed using Cochran's Q and I2-statistics. Severity of COVID-19 according to definitions applied in included studies was the main outcome. Sensitivity analyses were conducted for clusters of studies with equal definitions of severity. RESULTS Pooled analysis included data from 1906 laboratory-confirmed COVID-19 patients (43.9% females, median age ranging from 39 to 76 years). Patients with previous CVD had higher risk of severe COVID-19 than those without [RR 2.07, 95% confidence interval (CI) 1.52-2.81; p < 0.0001]. This association was also observed in clusters of studies that defined severe manifestation of the disease by clinical parameters (RR 1.44, 95% CI 1.22-1.71; p < 0.0001), necessity of intensive care (RR 2.79, 95% CI 1.83-4.24; p < 0.0001) and in-hospital death (RR 2.18, 95% CI 1.75-2.7; p < 0.0001). CONCLUSION A history of CVD might constitute an important risk factor of unfavorable clinical course of COVID-19  suggesting a need of tailored infection prevention and clinical management strategies for this population at risk