Protoliths and phase petrology of whiteschists

Whiteschists appear in numerous high- and ultrahigh-pressure rock suites and are characterized by the mineral assemblage kyanite+talc (+-quartz or coesite). We demonstrate that whiteschist mineral assemblages are well stable up to pressures of more than 4GPa but may already form at pressures of 0.5GPa. The formation of whiteschists largely depends on the composition of the protolith, which requires elevated contents of Al and Mg as well as low Fe, Ca, and Na contents, as otherwise chloritoid, amphibole, feldspar, or omphacite are formed instead of kyanite or talc. Furthermore, the stability field of the whiteschist mineral assemblage strongly depends on XCO2 and fO2: already at low values of XCO2, CO2 binds Mg to carbonates strongly reducing the whiteschist stability field, whereas high fO2 enlarges the stability field and stabilizes yoderite. Thus, the scarcity of whiteschist is not necessarily due to unusual P-T conditions, but to the restricted range of suitable protolith compositions and the spatial distribution of these protoliths: (1) continental sedimentary rocks and (2) hydrothermally and metasomatically altered felsic to mafic rocks. The continental sedimentary rocks that may produce whiteschist mineral assemblages typically have been deposited under arid climatic conditions in closed evaporitic basins and may be restricted to relatively low latitudes. These rocks often contain large amounts of the clay minerals palygorskite and sepiolite. Marine sediments generally do not yield whiteschist mineral assemblages as marine shales commonly have too high iron contents. Sabkha deposits may have too high CO2 contents. Protoliths of appropriate geochemical composition occur in and on continental crust. Therefore, whiteschist assemblages typically are only found in settings of continental collision or where continental fragments were involved in subduction. Our calculations demonstrate that whiteschists can form by closed-system metamorphism, which implies that the chemical and isotopic composition of these rocks provide constraints on the development of the protolith

Cold subduction and the formation of lawsonite eclogite - constraints from prograde evolution of eclogitized pillow lava from Corsica

International audienceA new discovery of lawsonite eclogite is presented from the Lancône glaucophanites within the Schistes Lustrés nappe at Défilé du Lancône in Alpine Corsica. The fine-grained eclogitized pillow lava and inter-pillow matrix are extremely fresh, showing very little evidence of retrograde alteration. Peak assemblages in both the massive pillows and weakly foliated inter-pillow matrix consist of zoned idiomorphic Mg-poor (<0.8 wt% MgO) garnet + omphacite + lawsonite + chlorite + titanite. A local overprint by the lower grade assemblage glaucophane + albite with partial resorption of omphacite and garnet is locally observed. Garnet porphyroblasts in the massive pillows are Mn rich, and show a regular prograde growth-type zoning with a Mn-rich core. In the inter-pillow matrix garnet is less manganiferous, and shows a mutual variation in Ca and Fe with Fe enrichment toward the rim. Some garnet from this rock type shows complex zoning patterns indicating a coalescence of several smaller crystallites. Matrix omphacite in both rock types is zoned with a rimward increase in XJd, locally with cores of relict augite. Numerous inclusions of clinopyroxene, lawsonite, chlorite and titanite are encapsulated within garnet in both rock types, and albite, quartz and hornblende are also found included in garnet from the inter-pillow matrix. Inclusions of clinopyroxene commonly have augitic cores and omphacitic rims. The inter-pillow matrix contains cross-cutting omphacite-rich veinlets with zoned omphacite, Si-rich phengite (Si = 3.54 apfu), ferroglaucophane, actinolite and hematite. These veinlets are seen fracturing idiomorphic garnet, apparently without any secondary effects. Pseudosections of matrix compositions for the massive pillows, the inter-pillow matrix and the cross-cutting veinlets indicate similar P-T conditions with maximum pressures of 1.9-2.6 GPa at temperatures of 335-420 °C. The inclusion suite found in garnet from the inter-pillow matrix apparently formed at pressures below 0.6-0.7 GPa. Retrogression during initial decompression of the studied rocks is only very local. Late veinlets of albite + glaucophane, without breakdown of lawsonite, indicate that the rocks remained in a cold environment during exhumation, resulting in a hairpin-shaped P-T path

SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types

The reference site collaborative network of the european innovation partnership on active and healthy ageing

Seventy four Reference Sites of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) have been recognised by the European Commission in 2016 for their commitment to excellence in investing and scaling up innovative solutions for active and healthy ageing. The Reference Site Collaborative Network (RSCN) brings together the EIP on AHA Reference Sites awarded by the European Commission, and Candidate Reference Sites into a single forum. The overarching goals are to promote cooperation, share and transfer good practice and solutions in the development and scaling up of health and care strategies, policies and service delivery models, while at the same time supporting the action groups in their work. The RSCN aspires to be recognized by the EU Commission as the principal forum and authority representing all EIP on AHA Reference Sites. The RSCN will contribute to achieve the goals of the EIP on AHA by improving health and care outcomes for citizens across Europe, and the development of sustainable economic growth and the creation of jobs

The ALICE experiment at the CERN LHC

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

The computation of chemical equilibrium and the distribution of Fe, Mn and Mg among sites and phases in olivines and garnets

A general algorithm for the computation of chemical equilibria in complex systems containing non-ideal solutions has been developed. The method is a G-minimization based on repeated linear and nonlinear programming steps. A computer program (THERIAK) based on this algorithm has been written and was used to solve a great variety of problems, ranging from a simple blast furnace calculation to liquid-liquid unmixing in a four component silicate melt. The computing times are in the magnitude of 1/2 to 2 seconds for each calculation. The method can also be used to test the consequences of thermodynamic models and data in systems of interest to many fields, including chemistry, geochemistry and metallurgy. Integrated powder diffraction intensities can be used to measure Mn-Mg and Fe-Mg site occupancies in olivines because of the difference in scattering factors between Mg and Mn or Fe. Theoretically calculated intensity ratios are subject to uncertainties from positional parameters (less than 3.5 % for peaks with a relative intensity greater than 25 %) and unknown charge distribution (up to 30 %). Several peak ratios are less subject to this last uncertainty and may be used to measure the site occupancies in olivines. 27 synthetic Fe-Mn-Mg olivines (800 °C, vacuum, with graphite) were investigated with Mossbauer spectroscopy and XRD intensity evaluation, producing occupancies accurate to approximately 0.03 per site. A thermodynamic speciation model represents the data very well. Preliminary Fe-Mn-Mg exchange experiments involving olivine and garnet place some limits on element distributions between these two minerals.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat

Petrology of High-Pressure Metapelites from the Adula Nappe (Central Alps, Switzerland)

High-pressure metamorphism in the Penninic Adula nappe (Central Alps, Switzerland reached eclogite facies conditions. Besides abundant mafic eclogite lenses, very few metapelitic rocks also preserved high-pressure relics, even though most of the felsic lithologies were retrogressed during a later amphibolite facies overprint. Calculations of equilibrium phase diagrams of whiteschist and sodic whiteschist assemblages reveal conditions of P>20 kbar at T ∼650°C. Common metapelitic assemblages (garnet + phengite + kyanite + quartz ± paragonite) are stable over a wide range in pressure and temperature. Calculations of the peak pressure conditions in the investigated metapelite samples are in good agreement with analogue calculations of eclogite samples. These results combined with structural investigations support a single P-T loop for this area with a Tertiary high-pressure event (Late Eocene) that affected the entire Adula napp

Protoliths and phase petrology of whiteschists

Whiteschists appear in numerous high- and ultrahigh-pressure rock suites and are characterized by the mineral assemblage kyanite + talc (+-quartz or coesite). We demonstrate that whiteschist mineral assemblages are well stable up to pressures of more than 4 GPa but may already form at pressures of 0.5 GPa. The formation of whiteschists largely depends on the composition of the protolith, which requires elevated contents of Al and Mg as well as low Fe, Ca, and Na contents, as otherwise chloritoid, amphibole, feldspar, or omphacite are formed instead of kyanite or talc. Furthermore, the stability field of the whiteschist mineral assemblage strongly depends on XCO2 and fO(2): already at low values of XCO2, CO2 binds Mg to carbonates strongly reducing the whiteschist stability field, whereas high fO(2) enlarges the stability field and stabilizes yoderite. Thus, the scarcity of whiteschist is not necessarily due to unusual P-T conditions, but to the restricted range of suitable protolith compositions and the spatial distribution of these protoliths: (1) continental sedimentary rocks and (2) hydrothermally and metasomatically altered felsic to mafic rocks. The continental sedimentary rocks that may produce whiteschist mineral assemblages typically have been deposited under arid climatic conditions in closed evaporitic basins and may be restricted to relatively low latitudes. These rocks often contain large amounts of the clay minerals palygorskite and sepiolite. Marine sediments generally do not yield whiteschist mineral assemblages as marine shales commonly have too high iron contents. Sabkha deposits may have too high CO2 contents. Protoliths of appropriate geochemical composition occur in and on continental crust. Therefore, whiteschist assemblages typically are only found in settings of continental collision or where continental fragments were involved in subduction. Our calculations demonstrate that whiteschists can form by closed-system metamorphism, which implies that the chemical and isotopic composition of these rocks provide constraints on the development of the protoliths