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Bernard S.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Horsfield B.,German Research Center for Geosciences
Annual Review of Earth and Planetary Sciences | Year: 2014

Shale gas systems serve as sources, reservoirs, and seals for unconventional natural gas accumulations. These reservoirs bring numerous challenges to geologists and petroleum engineers in reservoir characterization, most notably because of their heterogeneous character due to depositional and diagenetic processes but also because of their constituent rocks' fine-grained nature and small pore size-much smaller than in conventional sandstone and carbonate reservoirs. Significant advances have recently been achieved in unraveling the gaseous hydrocarbon generation and retention processes that occur within these complex systems. In addition, cutting-edge characterization technologies have allowed precise documentation of the spatial variability in chemistry and structure of thermally mature organic-rich shales at the submicrometer scale, revealing the presence of geochemical heterogeneities within overmature gas shale samples and, notably, the presence of nanoporous pyrobitumen. Such research advances will undoubtedly lead to improved performance, producibility, and modeling of such strategic resources at the reservoir scale. © 2014 by Annual Reviews. All rights reserved.

Saitta A.M.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Saija F.,CNR Institute for Chemical and Physical Processes
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014

The celebrated Miller experiments reported on the spontaneous formation of amino acids from a mixture of simple molecules reacting under an electric discharge, giving birth to the research field of prebiotic chemistry. However, the chemical reactions involved in those experiments have never been studied at the atomic level. Here we report on, to our knowledge, the first ab initio computer simulations of Miller-like experiments in the condensed phase. Our study, based on the recent method of treatment of aqueous systems under electric fields and on metadynamics analysis of chemical reactions, shows that glycine spontaneously forms from mixtures of simple molecules once an electric field is switched on and identifies formic acid and formamide as key intermediate products of the early steps of the Miller reactions, and the crucible of formation of complex biological molecules. © 2014 PNAS.

Bernard S.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Papineau D.,University College London
Elements | Year: 2014

The unambiguous identifi cation of graphitic carbons as remains of life in ancient rocks is challenging because fossilized biogenic molecules are inevitably altered and degraded during diagenesis and metamorphism of the host rocks. Yet, recent studies have highlighted the possible preservation of biosignatures carried by some of the oldest graphitic carbons. Laboratory simulations are increasingly being used to better constrain the transformations of organic molecules into graphitic carbons induced by sedimentation and burial processes. These recent research advances justify a reevaluation of the putative biogenicity of numerous ancient graphitic carbons, including the presumed oldest traces of life on Earth.

Miot J.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Benzerara K.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Kappler A.,University of Tübingen
Annual Review of Earth and Planetary Sciences | Year: 2014

Microbe-mineral interactions occur in diverse modern environments, from the deep sea and subsurface rocks to soils and surface aquatic environments. They may have played a central role in the geochemical cycling of major (e.g., C, Fe, Ca, Mn, S, P) and trace (e.g., Ni, Mo, As, Cr) elements over Earth's history. Such interactions include electron transfer at the microbe-mineral interface that left traces in the rock record. Geomicrobiology consists in studying interactions at these organic-mineral interfaces in modern samples and looking for traces of past microbe-mineral interactions recorded in ancient rocks. Specific tools are required to probe these interfaces and to understand the mechanisms of interaction between microbes and minerals from the scale of the biofilm to the nanometer scale. In this review, we focus on recent advances in electron microscopy, in particular in cryoelectron microscopy, and on a panel of electrochemical and synchrotron-based methods that have recently provided new understanding and imaging of the microbe-mineral interface, ultimately opening new fields to be explored. © 2014 by Annual Reviews. All rights reserved.

Chen Z.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Chen Z.,Lanzhou University | Biscaras J.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Shukla A.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry
Nanoscale | Year: 2015

We fabricated a graphene/few-layer InSe heterostructure photo-detector and solved a recurrent materials problem concerning degradation of ultra-thin atomic layers in air. This heterostructure has a largely enhanced performance explained by its fundamentally different mode of functioning with respect to the corresponding device without graphene. This journal is © The Royal Society of Chemistry.

Aleon J.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry
Earth and Planetary Science Letters | Year: 2016

A major unanswered question in solar system formation is the origin of the oxygen isotopic dichotomy between the Sun and the planets. Individual Calcium-Aluminum-rich inclusions (CAIs) from CV chondrites exhibit almost the full isotopic range, but how their composition evolved is still unclear, which prevents robust astrochemical conclusions. A key issue is notably the yet unsolved origin of the 16O-rich isotopic composition of pyroxene in type B CAIs. Here, I report an in-situ oxygen isotope study of the archetypal type B CAI USNM-3529-Z from Allende with emphasis on the isotopic composition of pyroxene and its isotopic and petrographic relationships with other major minerals. The O isotopic composition of pyroxene is correlated with indicators of magmatic growth, indicating that the pyroxene evolved from a 16O-poor composition and became progressively enriched in 16O during its crystallization, contrary to the long held assumption that pyroxene was initially 16O-rich. This variation is well explained by isotopic exchange between a 16O-poor partial melt having the isotopic composition of melilite and a 16O-rich gas having the isotopic composition of spinel, during pyroxene crystallization. The isotopic evolution of 3529-Z is consistent with formation in an initially 16O-rich environment where spinel and gehlenitic melilite crystallized, followed by a 16O-depletion associated with melilite partial melting and recrystallization and finally a return to the initial 16O-rich environment before pyroxene crystallization. This strongly suggests that the environment of CAI formation was globally 16O-rich, with local 16O-depletions systematically associated with high temperature events. The Al/Mg isotopic systematics of 3529-Z further indicates that this suite of isotopic changes occurred in the first 150 000 yr of the solar system, during the main CAI formation period. A new astrophysical setting is proposed, where the 16O-depletion occurs in an optically thin surface layer of the disk and may have originated by evaporation of 16O-poor interstellar dust or non-mass-dependant isotopic fractionation. © 2016 Elsevier B.V.

Vitale Brovarone A.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Beyssac O.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry
Earth and Planetary Science Letters | Year: 2014

Hybrid rocks formed by fluid-rock interactions at high-pressure (HP) metamorphic conditions are active players in the recycling of volatiles in subduction zones. Such rocks include chlorite-talc-amphibole-rich (± carbonate) rocks formed by chemical and mechanical mixing of mafic, ultramafic and sedimentary protoliths. Recent discovery of widespread formation of lawsonite-rich hybrid rocks extends the composition range of these rocks and their significance for volatile transfer to the deep Earth. In this study we quantify the drastic water enrichment across a metasomatic aureole characterized by intense chemical resetting and massive lawsonite precipitation in Alpine Corsica (France). The chemical composition of the metasomatic product, which in many cases approaches the CASH system, favors (i) the precipitation of lawsonite and the unexpected reincorporation of free water at HP conditions, and (ii) the stability of lawsonite at higher temperature and at greater depth compared to the MORB + H2O system. We conclude that these hybrid rocks may contribute to transfer water to great depth in subduction, with implications for water cycling to the mantle. © 2014 Elsevier B.V.

Dabrowski Y.,Camille Jordan Institute | Brouder C.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry
Communications in Mathematical Physics | Year: 2014

The space (formula presented) of distributions having their wavefront sets in a closed cone (formula presented)has become important in physics because of its role in the formulation of quantum field theory in curved spacetime. In this paper, the topological and bornological properties of (formula presented) and its dual (formula presented) are investigated. It is found that (formula presented)is a nuclear, semi-reflexive and semi-Montel complete normal space of distributions. Its strong dual (formula presented) is a nuclear, barrelled and (ultra)bornological normal space of distributions which, however, is not even sequentially complete. Concrete rules are given to determine whether a distribution belongs to (formula presented) , whether a sequence converges in (formula presented) and whether a set of distributions is bounded in (formula presented) . © 2014, Springer-Verlag Berlin Heidelberg.

Mauger A.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Julien C.,CNRS Physical Chemistry of Electrolytes and Interfacial Nanosystems
Ionics | Year: 2014

The research on the electrodes of Li-ion batteries aims to increase the energy density and the power density, improve the calendar and the cycling life, without sacrificing the safety issues. A constant progress through the years has been obtained owing to the surface treatment of the particles, in particular the coating of the particles with a layer that protects the core region from side reactions with the electrolyte, prevents the loss of oxygen, and the dissolution of the metal ions in the electrolyte, or simply improve the conductivity of the powder. The purpose of the present work is to review the different surface modifications that have been tried in the past for the different electrodes that are currently commercialized, or considered as promising, including the three families of positive electrodes (lamellar, spinel, and olivine families) and the three negative electrodes (carbon, Li4Ti5O12, and silicon). The role of the different coats used to improve either the surface conductivity, or the thermal stability, or the structural integrity is discussed. The limits in the efficiency of these different coats are also analyzed along with the understanding of the surface modifications that have been proposed. © 2014 Springer-Verlag Berlin Heidelberg.

Touret J.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry
Geoscience Frontiers | Year: 2014

Recalling some of the most important events and persons during his education and career, the author sketches his growth from a young engineer, educated in the sanctuary of solid state reactions, to an involved fully devoted scientific career for the study of fluids in the deep Earth. Most important in this respect was the discovery of CO2 inclusions in granulites, which triggered years of discussion on fluid-absent or fluid-assisted granulite metamorphism. To some extent, this debate is a continuation of the former granite controversy, but it shows also how the famous battle of "soaks against pontiffs" could have been easily avoided.

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