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1. Implications of fracturing mechanisms and fluid pressure on earthquakes and fault slip data in the east Iceland rift zone

Author: Géoazur (GEOAZUR) ; CNRS - Institut de recherche pour le développement [IRD] - INSU - Université Nice Sophia Antipolis (UNS) - Université Pierre et Marie Curie (UPMC) - Paris VI - Observatoire de la Côte d'Azur, Institut des Sciences de la Terre de Paris (iSTeP) ; Université Pierre et Marie Curie (UPMC) - Paris VI - CNRS, Environnements, Dynamiques et Territoires de la Montagne (EDYTEM) ; Université de Savoie - CNRS, Plateaux, R., Bergerat, F., Béthoux, N., Villemin, Th., Gerbault, M., Géoazur (GEOAZUR) ; CNRS - Institut de recherche pour le développement [IRD] - INSU - Université Nice Sophia Antipolis (UNS) - Université Pierre et Marie Curie (UPMC) - Paris VI - Observatoire de la Côte d'Azur, Institut des Sciences de la Terre de Paris (iSTeP) ; Université Pierre et Marie Curie (UPMC) - Paris VI - CNRS, Environnements, Dynamiques et Territoires de la Montagne (EDYTEM) ; Université de Savoie - CNRS, Plateaux, R., Bergerat, F., Béthoux, N., Villemin, Th., and Gerbault, M.
Abstract: International audience, Comparison of the eroded off-rift zone left inactive by plate motion with the inner active seismic rift zone allows us to constrain the fracturing mechanisms. In eastern off-rift zone, we measured 423 fault slips (including normal and strike-slip faults). Inversion of fault slip data reveals the parallelism of the minimum stress (σ3) computed for the normal and for the strike-slip faulting, and consistency with the direction of plate divergence. North of the Vatnajökull, in the active rift zone, we analysed 14,250 earthquakes recorded by the Icelandic Meteorological Office (IMO) between 2004 and 2009, especially northeast of the Askja volcano. Two main average focal depths were determined at 5 km (Herðubreið table mountain) and 15 km (Upptyppingar hyaloclastite ridge). The double couple focal mechanisms determined by IMO revealed that more than half of the mechanisms are strike-slip. Faulting type both in active and off-rift zone reveals an unusual importance of strike-slip regime in such an extensional tectonic context. This can be explained by stress permutations (σ1/σ2). Similarities in terms of stress orientations and type of faulting are observed both in the old and present-day rift zones. We assume that the seismic events may be generated by rapid deep magma intrusion, also associated with shallower hydrothermal activities. We thus propose that the presence of fluids, shear failure (double couple focal mechanism) and stress permutations in both active and off-rift zones are closely linked. Assuming a Drucker-Prager failure criterion, we evaluated analytically that a state near of lithostatic pore pressure is a necessary condition for shear failure at shallow (5 km) and deep (15 km) depth, in a simple context of crustal extension that allows for stress permutations. However, processes favouring stress permutations cannot be further constrained from our observations since the dynamics of fluid, materiel heterogeneity and post-glacial rebound can also play a sign

2. Parallel between the isotopic composition of coccolith calcite and carbon levels across Termination II: developing a new paleo-CO$_2$ probe

Author: Godbillot, Camille, Minoletti, Fabrice, Bassinot, Franck, Hermoso, Michaël, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Paléocéanographie (PALEOCEAN), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Université du Littoral Côte d'Opale (ULCO), ANR-17-CE01-0004,CARCLIM,Les coccolithophoridés : acteurs et enregistreurs des changements climatiques(2017), Institut des Sciences de la Terre de Paris [iSTeP], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE], Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG], Université du Littoral Côte d'Opale [ULCO], Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Sorbonne Université (SU)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS
Abstract: Beyond the pCO2 records provided by ice core measurements, the quantification of atmospheric CO2 concentrations and changes thereof relies on proxy data, the development of which represents a foremost challenge in paleoceanography. In the paleoceanographic toolbox, the coccolithophores occupy a notable place, as the magnitude of the carbon isotopic fractionation between ambient CO2 and a type of organic compounds that these photosynthetic microalgae synthesize (the alkenones) represents a relatively robust proxy to reconstruct past atmospheric CO2 concentrations during the Cenozoic. The isotopic composition of coeval calcite biominerals found in the sediments and also produced by the coccolithophores (the coccoliths) have been found to record an ambient CO2 signal through culture and sediment analyses. These studies have, however, not yet formalized a transfer function that quantitatively ties the isotopic composition of coccolith calcite to the concentrations of aqueous CO2 and, ultimately, to atmospheric CO2 levels. Here, we make use of a microseparation protocol to compare the isotopic response of two size-restricted coccolith assemblages from the North Atlantic to changes in surface ocean CO2 during Termination II (ca. 130–140 ka). Performing paired measurements of the isotopic composition (δ13C and δ18O) of relatively large and small coccoliths provides an isotopic offset that can be designated as a “differential vital effect”. We find that the evolution of this offset follows that of aqueous CO2 concentrations computed from the ice core CO2 curve and an independent temperature signal. We interpret this biogeochemical feature to be the result of converging carbon fixation strategies between large and small cells as the degree of carbon limitation for cellular growth decreases across the deglaciation. We are therefore able to outline a first-order trend between the coccolith differential vital effects and aqueous CO2 in the range of Quaternary CO2 concentrations. Although this study would benefit from further constraints on the other controls at play on coccolith geochemistry (growth rate, air–sea gas exchange, etc.), this test of the drivers of coccolith Δδ13C and Δδ18O in natural conditions is a new step in the development of a coccolith paleo-CO2 probe.
Published: 2022

3. Did the Pleistocene tectonics in the Alboran Sea change the distribution and origin of submarine landslides

Author: Lafosse, M. (Manfred), d'Acremont, E. (Elia), Lafuerza, S. (Sara), Rabaute, A. (Alain), Jollivet-Castelot, M. (Martin), Alonso, B. (Belén), Ercilla, G. (Gemma), Vazquez, J-T. (Juan-Tomas), Gorini, C. (Christian), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Utrecht University [Utrecht], Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Instituto de Ciencias del Mar de Barcelona (ICM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Instituto Español de Oceanografía (IEO), Málaga., EGU, Institut des Sciences de la Terre de Paris [iSTeP], Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG], and Instituto de Ciencias del Mar de Barcelona [ICM]
Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract: European Geosciences Union (EGU) General Assembly, 19-30 Apr 2021.-- 1 page, The tectonics of the Alboran Sea control the distribution of topographic highs and depressions, influencing the water masses' paths controlling the deep basins sedimentation rates. Altogether tectonics and deep currents shaped the seafloor on which we map active faults, contourites, pockmarks, and submarine landslides. Recent numerical models highlight that some of those landslides can generate tsunamis waves on nearby coastal areas, creating the need to describe better and understand those seabed features. Consequently, we put together bathymetric and seismic data to measure Pleistocene slides affecting the deep Alboran basin in an unprecedented collective effort. We mapped and relatively dated 66 mass transport deposits (MTDs) in the West Alboran and Pytheas fields on the north and south flank of the Alboran Ridge. We measured their surfaces, decompacted volumes, slopes, run out, scars heights, scars elevations, and described their type (debris flow or slide) qualitatively from their echo facies. When possible, we also measured the run-off from the scar. We investigated the factor of safety (FOS) and computed based seismic moments based on empirical relationship and faults geometry to characterize the preconditioning factors and triggering mechanisms. The first important result is that post-1.12 Ma MTDs mobilized the most important volumes, in line with the Alboran Sea's topographic highs. Second, seismic lines and the bathymetric images evidence blind reverse faults related to fluid escapes that could contribute to local overpressures in shallow contouritic sediments. Third, we show that local slopes are too flat to allow slopes to destabilize under gravity force only, suggesting that other causal factors need to be considered. Fourth, known seismicity on strike-slip faults in the Alboran Sea is unlikely to trigger MTDs in most investigated areas, suggesting that a combination of preconditioning factors, such as local overpressures and/or reduced strength properties with reverse faults activity, seems the most plausible explanation to trigger the observed MTDs. The overall results highlight that the Alboran tectonics explain the slope destabilization, with varying local sediment properties. However, those properties and past overpressures, deformations, and fluid flows remain to be locally detailed. Future works involving sediments characterizations and dating will follow after the ALBACORE survey scheduled in 2021
Published: 2021

4. Clay mineralogical characteristics at the Permian–Triassic Shangsi section and their paleoenvironmental and/or paleoclimatic significance

Author: François Baudin, Qinglai Feng, Guozhen Xu, Jean-François Deconinck, Pierre Pellenard, Jun Shen, Ludovic Bruneau, Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences [Wuhan] (CUG), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [Dijon] ( BGS ), AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), China University of Geosciences, Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Biogéosciences [UMR 6282] (BGS), and Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Mineralogy, Weathering, engineering.material, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, chemistry.chemical_compound, Kaolinite, Chlorite, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, Terrigenous sediment, Paleontology, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, 15. Life on land, Diagenesis, Illite crystallinity, chemistry, 13. Climate action, Illite, engineering, Clay minerals, Geology
Abstract: High–resolution clay mineralogical investigations were conducted on the Permian–Triassic (P–Tr) carbonate– and siliceous rocks from the Shangsi section, South China. The clay mineralogy is dominated by illite and illite/smectite mixed–layers (I/S) throughout the sampled section with subordinate chlorite and vermiculite emerging from bed 24 (approaching the End–Permian mass extinction horizon–EPME) onwards. Positive correlations of clay fraction with mainly land–derived TiO2 and magnetic susceptibility (MS) indicate a primary continental origin of the clay minerals. Rock–Eval pyrolysis analysis, palynomorph coloration, scanning electron microscope (SEM) and Transmission Electron Microscope (TEM) observations, all suggest that the rocks experienced thermal diagenesis which mainly promotes illitization processes of smectite clay minerals while discrete clay minerals are merely affected. Despite this diagenetic effect, clay minerals still carry valuable paleoenvironmental and paleoclimatic information in the Shangsi section. The overall illitic composition of the clay minerals and nearly absence of kaolinite suggest a general semi–arid condition during the P–Tr interval. Appearance of chlorite from bed 24 onwards suggests further aridification compared to the Late Permian. Occurrence of vermiculite from beds 24–28 in association with abundant volcanogenic materials, most negative δ13Ccarb values as well as enhanced soil–derived moretane abundance, suggests catastrophic soil erosion and likely soil acidification during the P–Tr transition in the source area(s) in relation with the active volcanism in that time. Further, decrease of chemical weathering and increase of physical weathering are indicated by increased input of primary clay minerals such as chlorite, a better illite crystallinity and increase of Al2O3/TiO2 ratios. A climate cooling period corresponding to the Clarkina changxingensis–Clarkina deflecta conodont zone to the lower Clarkina zhangi conodont zone is indicated by higher abundance of illite, lower terrigenous TiO2, MS and Al2O3/TiO2 in comparison with the overlying uppermost Permian strata.
Published: 2017

5. Experimental evidence for wall-rock pulverization during dynamic rupture at ultra-high pressure conditions

Author: Loïc Labrousse, François Renard, Bjørn Jamtveit, Helen M. Freeman, Alexandre Schubnel, Nadege Hilairet, Jörg Renner, Yanbin Wang, Sarah Incel, Timm John, Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Unité Matériaux et Transformations - UMR 8207 (UMET), Institut de Chimie du CNRS (INC)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Institut des Sciences de la Terre (ISTerre), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), ANR-12-JS06-0003,DELF,Séismes Profonds : du Laboratoire au Terrain(2012), European Project: 604713,EC:FP7:PEOPLE,FP7-PEOPLE-2013-ITN,ZIP(2013), European Project: 669972,H2020,ERC-2014-ADG,DIME(2015), Laboratoire de géologie de l'ENS (LGE), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut National de la Recherche Agronomique (INRA), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Université de Lille, CNRS, INRA, ENSCL, Laboratoire de géologie de l'ENS [LGENS], Institut des Sciences de la Terre de Paris [iSTeP], Unité Matériaux et Transformations - UMR 8207 [UMET], and Institut des Sciences de la Terre [ISTerre]
Subjects: Shearing (physics), Blueschist, Nanostructure, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, Overburden pressure, 01 natural sciences, Geophysics, Brittleness, Shear (geology), 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Ultimate tensile strength, Earth and Planetary Sciences (miscellaneous), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Composite material, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, 0105 earth and related environmental sciences, Wall rock
Abstract: The mechanisms triggering intermediate and deep earthquakes have puzzled geologists for several decades. There is still no consensus concerning whether such earthquakes are triggered by brittle or ductile mechanisms. We performed a deformation experiment on a synthetic lawsonite-bearing blueschist at a confining pressure of 3 GPa and temperatures from 583 to 1,073 K. After deformation, the recovered sample reveals conjugated shear fractures. Garnet crystals are dissected and displaced along these narrow faults and reveal micro- and nanostructures that resemble natural pulverization structures as well as partial amorphization. Formation of such structures at low confining pressures is known to require high tensile stresses and strain rates and is explained by the propagation of a dynamic shear rupture. The absence of shearing in the pulverized wall rock is taken as evidence that these structures pre-date the subsequent heat-producing frictional slip. In analogy to observations at low pressure we infer that the garnet structures in our experiment result from rapid propagation of a shear fracture even at the high pressure exerted on the sample and thus suggest that brittle deformation is possible at lower crustal to upper mantle depths.
Published: 2019

6. Gravity complexes as a focus of seafloor fluid seepage: the Rio Grande Cone, SE Brazil

Author: Ketzer, M., Praeg, Daniel, Augustin, A., Rodrigues, L., Steiger, A., Rahmati-Abkenar, M., Viana, A., Miller, D., Malinverno, A., Dickens, G., Cupertino, J., Linneaus University, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Pontifical Catholic University of Rio Grande do Sul (PUC-RS), Universidade Federal do Rio Grande (FURG), Petrobras [Rio de Janeiro], Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Trinity College Dublin, and European Project: 656821,H2020,H2020-MSCA-IF-2014,SEAGAS(2016)
Subjects: Multidisciplinary, Geochemistry, Solid Earth sciences, [SDU]Sciences of the Universe [physics], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, Sedimentology
Abstract: Seafloor methane emissions can affect Earth’s climate and ocean chemistry. Vast quantities of methane formed by microbial decomposition of organic matter are locked within gas hydrate and free gas on continental slopes, particularly in large areas with high sediment accumulations such as deep-sea fans. The release of methane in slope environments has frequently been associated with dissociation of gas hydrates near the edge of the gas hydrate stability zone on the upper slope, with discharges in greater water depths less understood. Here we show, using data from the Rio Grande Cone (western South Atlantic), that the intrinsic, gravity-induced downslope collapse of thick slope sediment accumulations creates structures that serve as pathways for gas migration, unlocking methane and causing seafloor emissions via giant gas flares in the water column. The observed emissions in the study region (up to 310 Mg year−1) are three times greater than estimates for the entire US North Atlantic margin and reveal the importance of collapsing sediment accumulations for ocean carbon cycling. Similar outgassing systems on the Amazon and Niger fans suggest that gravity tectonics on passive margins is a common yet overlooked mechanism driving massive seafloor methane emissions in sediment-laden continental slopes.
Published: 2023

7. Long-Term Cyclicities in Phanerozoic Sea-Level Sedimentary Record and their Potential Drivers

Author: Bruno Galbrun, Slah Boulila, Bilal U. Haq, Jacques Laskar, Nathan Hara, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Mécanique Céleste et de Calcul des Ephémérides ( IMCCE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Solar System, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], ~9.3, Vertical and radial motions, Astrophysics::Cosmology and Extragalactic Astrophysics, 010502 geochemistry & geophysics, Oceanography, Geologic record, 01 natural sciences, Supercontinent, Physics::Geophysics, Paleontology, 0103 physical sciences, Phanerozoic, Astrophysics::Solar and Stellar Astrophysics, ~91 and ~250 Myr sea-level periodicities, 010303 astronomy & astrophysics, ~36, Sea level, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Milankovitch, [PHYS]Physics [physics], Global and Planetary Change, Milankovitch cycles, Tectonics, Earth's climate, Solar System periodicities, 13. Climate action, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Cenozoic, Geology
Abstract: Cyclic sedimentation has varied at several timescales and this variability has been geologically well documented at Milankovitch timescales, controlled in part by climatically (insolation) driven sea-level changes. At the longer (tens of Myr) timescales connection between astronomical parameters and sedimentation via cyclic solar-system motions within the Milky Way has also been proposed, but this hypothesis remains controversial because of the lack of long geological records. In addition, the absence of a meaningful physical mechanism that could explain the connection between climate and astronomy at these longer timescales led to the more plausible explanation of plate motions as the main driver of climate and sedimentation through changes in ocean and continent mass distribution on Earth. Here we statistically show a prominent and persistent ~36 Myr sedimentary cyclicity superimposed on two megacycles (~250 Myr) in a relatively well-constrained sea-level (SL) record of the past 542 Myr (Phanerozoic eon). We also show two other significant ~9.3 and ~91 Myr periodicities, but with lower amplitudes. The ~9.3 Myr cyclicity was previously attributed to long-period Milankovitch band based on the Cenozoic record. However, the ~91 Myr cyclicity has never been observed before in the geologic record. The ~250 Myr cyclicity was attributed to the Wilson tectonic (supercontinent) cycle. The ~36 Myr periodicity, also detected for the first time in SL record, has previously been ascribed either to tectonics or to astronomical cyclicity. Given the possible link between amplitudes of the ~36 and ~250 Myr cyclicities in SL record and the potential that these periodicities fall into the frequency band of solar system motions, we suggest an astronomical origin, and model these periodicities as originating from the path of the solar system in the Milky Way as vertical and radial periods that modulate the flux of cosmic rays on Earth. Our finding of the ~36 Myr SL cyclicity lends credibility to the existing hypothesis about the imprint of solar-system vertical period on the geological record. The ~250 Myr megacycles are tentatively attributed to a radial period. However, tectonic causal mechanisms remain equally plausible. The potential existence of a correlation between the modeled astronomical signal and the geological record may offer an indirect proxy to understand the structure and history of the Milky Way by providing a 542 Myr long record of the path of the Sun in our Galaxy.
Published: 2018

8. Reservoir Ages in the Western Tropical North Atlantic from One Coral off Martinique Island (Lesser Antilles)

Author: Eric Douville, Elsa Cortijo, Dominique Blamart, Lucile Bonneau, Edwige Pons-Branchu, Martine Paterne, Nathalie Feuillet, Christophe Colin, Jennifer Weill-Accardo, Guy Cabioch, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CNRS - ORSTOM Paléohydrologie, Paléoclimatique Continentales, Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Paléocéanographie (PALEOCEAN), Nanyang Technological University [Singapour], Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Universität Heidelberg [Heidelberg], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Universität Heidelberg [Heidelberg] = Heidelberg University, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] ( LSCE ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique du Globe de Paris ( IPGP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -IPG PARIS-Université Paris Diderot - Paris 7 ( UPD7 ) -Université de la Réunion ( UR ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques ( LOCEAN ), Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Centre National de la Recherche Scientifique ( CNRS ), Centre de Recherches Pétrographiques et Géochimiques ( CRPG ), Université de Lorraine ( UL ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre de Paris ( iSTeP ), and Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, 010506 paleontology, Archeology, Lesser Antilles, 010504 meteorology & atmospheric sciences, δ18O, Coral, location.country, stable isotopes, 01 natural sciences, law.invention, volcanic effects, location, marine reservoir ages, law, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, Martinique, 14. Life underwater, Radiocarbon dating, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, coral, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, biology, Volcanic arc, biology.organism_classification, Oceanography, Volcano, 13. Climate action, Martinique island, General Earth and Planetary Sciences, Siderastrea siderea, Geology
Abstract: Sea surface reservoir ages (R) are reported from radiocarbon (14C) measurements of the annual growth bands of coral Siderastrea siderea collected on the Atlantic coast off Martinique Island, in the Lesser Antilles volcanic arc. Mean values of R are similar between 1835 and 1845 during pre-anthropogenic times at 385±30 yr and between 1895 and 1905 at 382±20 yr when there was a huge eruption from the Montagne Pelée volcano in 1902–1903. Limited 14C aging of sea surface (~40 yr) may be due to enhanced volcanic activity. Variability of R is slightly greater during 1835–1845 than during 1895–1905. It is linked to a moderate increase of ∆14C of 5‰, strengthened by a clear increase of δ18O of 0.4‰. This is attributed to a decrease of the northward advection of the South Atlantic Waters into the western tropical North Atlantic and Caribbean Sea and relative enhanced westward flux of the tropical North Atlantic surface waters, the southern waters having lower values of 14C and δ18O than the North Atlantic ones. From 1835 to 1845, the fraction of the South Atlantic Waters transported up to Martinique Island was reduced from 25% to 15%.
Published: 2018

9. Weak Tectono-Magmatic Relationships along an Obliquely Convergent Plate Boundary: Sumatra, Indonesia

Author: Laura Sandri, Subagyo Pramumijoyo, Michel Sébrier, Valerio Acocella, Olivier Bellier, Centre européen de recherche et d'enseignement de géosciences de l'environnement ( CEREGE ), Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Collège de France ( CdF ) -Institut National de la Recherche Agronomique ( INRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ), Istituto Nazionale di Geofisica e Vulcanologia, Déformations, sismotectonique, imagerie, relief ( DéSIR ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Palermo (INGV), Déformations, sismotectonique, imagerie, relief (DéSIR), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Acocella, Valerio, Bellier, Olivier, Sandri, Laura, Sebrier, Michel, and Pramumijoyo, Subagyo
Subjects: strain partitioning, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [ SDU.STU.VO ] Sciences of the Universe [physics]/Earth Sciences/Volcanology, Volcanism, 010502 geochemistry & geophysics, 01 natural sciences, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Convergent boundary, lcsh:Science, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, volcanism, geography.geographical_feature_category, Volcanic arc, Volcanic belt, Transtension, Sumatra, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, [ SDU.STU.TE ] Sciences of the Universe [physics]/Earth Sciences/Tectonics, Strain partitioning, Tectonics, oblique convergence, Sinistral and dextral, strike-slip faulting, General Earth and Planetary Sciences, lcsh:Q, Geology, Seismology
Abstract: International audience; The tectono-magmatic relationships along obliquely convergent plate boundaries, where strain partitioning promotes strike-slip structures along the volcanic arc, are poorly known. Here it is unclear if and, in case, how the strike-slip structures control volcanic processes, distribution and size. To better define the possible tectono-magmatic relationships along strike-slip arcs, we merge available information on the case study of Sumatra (Indonesia) with field structural data. The Sumatra arc (entire volcanic belt) consists of 48 active volcanoes. Of these, 46% lie within 10 km from the dextral Great Sumatra Fault (GSF), which carries most horizontal displacement on the overriding plate, whereas 27% lie at >20 km from the GSF. Among the volcanoes at
Published: 2018

10. Macroscopic electrostatic effects in ATR-FTIR spectra of modern and archeological bones

Author: Xavier Gallet, Loïc Ségalen, Julie Aufort, Christian Brouder, Christel Gervais, Etienne Balan, Matthieu Lebon, Institut de minéralogie, de physique des matériaux et de cosmochimie ( IMPMC ), Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique ( CNRS ), Histoire naturelle de l'Homme préhistorique ( HNHP ), Muséum National d'Histoire Naturelle ( MNHN ) -Université de Perpignan Via Domitia ( UPVD ) -Centre National de la Recherche Scientifique ( CNRS ), Biominéralisations et environnements sédimentaires ( BES ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé ( SMiLES ), Laboratoire de Chimie de la Matière Condensée de Paris ( LCMCP ), Centre National de la Recherche Scientifique ( CNRS ) -Collège de France ( CdF ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Collège de France ( CdF ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Histoire naturelle de l'Homme préhistorique (HNHP), Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Biominéralisations et environnements sédimentaires (BES), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé (SMiLES), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), and Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)
Subjects: fossilization, 010506 paleontology, Materials science, Enamel paint, ATR-FTIR spectroscopy, Atr ftir spectroscopy, Infrared spectroscopy, electrostatic properties, 010502 geochemistry & geophysics, 01 natural sciences, bone, Apatite, Diagenesis, Ftir spectra, Biomaterials, Geophysics, Geochemistry and Petrology, visual_art, visual_art.visual_art_medium, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, [ SDU.STU.MI ] Sciences of the Universe [physics]/Earth Sciences/Mineralogy, 0105 earth and related environmental sciences, Nuclear chemistry, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy, [ SDU.STU.PG ] Sciences of the Universe [physics]/Earth Sciences/Paleontology
Abstract: International audience; Bones mostly consist of composite materials based on almost equivalent volume fractions of mineral (apatite) and organic (collagen) components. Accordingly, their infrared spectroscopic properties should reflect this composite nature. In this letter, we show by theory and experiment that the variability of the strong phosphate bands in the ATR-FTIR spectra of a series of modern and archeological bone samples can be related to electrostatic interactions affecting apatite particles and depending on the bone collagen content. Key parameters controlling the shape of these bands are the mineral volume fraction and the dielectric constant of the embedding matrix. The magnitude of these effects is larger than the one related to microscopic changes of the apatite structure. Consequently, the interplay of microscopic and macroscopic parameters should be considered when using FTIR spectroscopy to monitor the preservation state of bioapatite during diagenetic and fossilization processes, especially during the degradation of the organic fraction of bone.
Published: 2018

11. 3D structural and thermal modelling of Mesozoic petroleum systems in the Po Valley Basin, northern Italy

Author: Paul Ryan, Claudio Turrini, François Roure, Olivier Lacombe, Barbara Bosica, Peter Shiner, CTGeolConsulting, Petroceltic Italia, Petroceltic International plc, Déformations, sismotectonique, imagerie, relief (DéSIR), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Utrecht University [Utrecht], IFP Energies nouvelles (IFPEN), Déformations, sismotectonique, imagerie, relief ( DéSIR ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), IFP Energies nouvelles ( IFPEN ), and Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: 020209 energy, 02 engineering and technology, Structural basin, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, Geochemistry and Petrology, 0202 electrical engineering, electronic engineering, information engineering, Earth and Planetary Sciences (miscellaneous), Petrology, Geomorphology, [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology, 0105 earth and related environmental sciences, Maturity (geology), geography, geography.geographical_feature_category, Geology, Sedimentary basin, Overpressure, Fuel Technology, chemistry, Source rock, 13. Climate action, Basin modelling, Petroleum, Carbonate, Economic Geology, [ SDU.STU.AG ] Sciences of the Universe [physics]/Earth Sciences/Applied geology
Abstract: International audience; 1D and 3D basin modelling was performed to investigate the Mesozoic carbonate petroleum systems of the Po Valley Basin (northern Italy), through integration of a recent 3D structural model of the study area with the distribution of potential Triassic source rocks, rock properties and heat flow models.Results from standard 1D maturity models show significant overprediction of the thermal maturity of deep Triassic carbonates in the western Po Valley, unless the effect of the substantial overpressure observed in these sequences is incorporated into the model. In order to further test this observation, two thermal scenarios were applied to the Po Valley 3D geo-volume: one based on the actual geological heat flow and a second model based on a reduced heat flow as a proxy for the delaying effect of overpressure on hydrocarbon maturation. The predictions of these two models were then compared with the observed hydrocarbon distribution in the western Po Valley.Both thermal scenarios are broadly consistent with the observed hydrocarbon distribution at the scale of the basin but, in detail, the overpressure model provides a better match between the predicted charge available from the kitchen area's post-critical moment and observed volumes of hydrocarbons initially in place within the traps, as well as with the observed and predicted hydrocarbon phases, as measured by the gas/oil ratio (GOR) of the fluids. Overpressure probably significantly delayed hydrocarbon maturation in the western domain of the basin, confirming results from previous studies.Beyond regional implications, and despite its relative simplicity and inherent uncertainties, the adopted approach demonstrates the potential of a consistent 3D integration of the thermostructural history of sedimentary basins to constrain the geometry and structural evolution of hydrocarbon-bearing traps, as well as the generation and migration of hydrocarbons into these traps.
Published: 2018

12. A sedimentological oxymoron: highly evolved glauconite of earliest diagenetic origin

Author: Tribovillard, Nicolas, Bout-Roumazeilles, Viviane, Guillot, François, Baudin, François, Deconinck, Jean-François, Abraham, Romain, Ventalon, Sandra, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] (BGS), and Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Authigenic minerals, Boulonnais, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Late Jurassic, Tithonian, General Earth and Planetary Sciences, Glauconite, Diagenesis, General Environmental Science
Abstract: International audience; This work examines the possibility of a rapid formation of glauconite in a relatively shallow platform environment (below fair-weather wave baseline). The materials studied here are uppermost Jurassic alternations of carbonate beds and marly interbeds, namely, the Assises de Croï Formation of the Boulonnais area (northernmost France). The carbonate beds yield field evidences of an early diagenetic origin and both beds and interbeds contain glauconite, questioning the duration of formation of the glauconite, relative to that of the diagenetic carbonate beds. Carbon and oxygen stable isotope composition of the carbonate beds confirm an early diagenetic growth. Contrasted grain-size distribution patterns of glauconite and quartz grain populations (isolated after acid digestion and magnetic separation) evidenced that glauconite formed after sediment deposition. Glauconite formation allegedly requires protracted episodes of ion capture from the water column, which is no longer possible when glauconite gets trapped within authigenic carbonates. Therefore, in-situ glauconite formation preceded carbonate authigenesis. Yet, the chemical composition of grains (Fe and K) typifies glauconite as highly evolved, meaning that its formation must have lasted over times, according to conventional views. Consequently, our results challenge these conventional views and confirm that glauconite can form in relatively shallow environments (which has been already brought to light previously) and it is concluded that early diagenetic glauconite can be markedly enriched in both K and Fe, which is an unprecedented result.
Published: 2023

13. The East-Mayotte new volcano in the Comoros Archipelago: structure and timing of magmatic phases inferred from seismic reflection data

Author: Charles Masquelet, Sylvie Leroy, Matthias Delescluse, Nicolas Chamot-Rooke, Isabelle Thinon, Anne Lemoine, Dieter Franke, Louise Watremez, Philippe Werner, Fabien Paquet, Carole Berthod, Victor Cabiativa Pico, Daniel Sauter, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and ANR-19-CE31-0018,COYOTES,COmores & maYotte : vOlcanisme, TEctonique et Sismicité(2019)
Subjects: Volcanism, Comoros Archipelago, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Mayotte, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, General Earth and Planetary Sciences, Fani Maore volcano, FaniMaore volcano, Seismic reflection, General Environmental Science
Abstract: A multichannel seismic reflection profile acquired during the SISMAORE cruise (2021) provides the first in-depth image of the submarine volcanic edifice, named Fani Maore, that formed 50 km east of Mayotte Island (Comoros Archipelago) in 2018–2019. This new edifice sits on a ∼140 m thick sedimentary layer, which is above a major, volcanic layer up to ∼1 km thick and extends over 120 km along the profile. This volcanic unit is made of several distinct seismic facies that indicate successive volcanic phases. We interpret this volcanic layer as witnessing the main phase of construction of the Mayotte Island volcanic edifice. A ∼2.2–2.5 km thick sedimentary unit is present between this volcanic layer and the top of the crust. A complex magmatic feeder system is observed within this unit, composed of saucer-shape sills and seal bypass systems. The deepest tip of this volcanic layer lies below the top-Oligocene seismic horizon, indicating that the volcanism ofMayotte Island likely began around 26.5Ma, earlier than previously assumed., Un profil de sismique réflexion multitrace acquis lors de la campagne océanographique SISMAORE (2021) apporte la première image en profondeur du volcan sous-marin Fani Maore, qui s’est formé à 50 km à l’est de l’île de Mayotte (archipel des Comores) en 2018–2019. Ce nouvel édifice repose sur une première couche sédimentaire d’environ 140 m d’épaisseur au-dessus d’une couche volcanique majeure épaisse de 1 km et qui s’étend sur 120 km le long du profil. Cette dernière unité volcanique est constituée de plusieurs faciès sismiques distincts qui indiquent des phases volcaniques successives. Nous interprétons cette couche volcanique comme le témoin de la phase principale de construction de l’édifice volcanique de l’île de Mayotte. Une couverture sédimentaire de 2.2–2.5 km d’épaisseur est présente entre cette couche volcanique et le toit de la croûte. On y observe de nombreux sills en forme de soucoupe ainsi que des zones à faciès de remontées de fluides, dessinant un système d’alimentation magmatique complexe sous la principale couche volcanique. L’extrémité la plus profonde de cette couche volcanique se place en dessous de l’horizon sismique de l’Oligocène supérieur et indique que le volcanisme de l’île de Mayotte a probablement commencé vers 26.5 Ma, plus tôt que ce qui était supposé auparavant.
Published: 2023

14. High resolution ion microprobe investigation of the δ18O of carbonate cements (Jurassic, Paris Basin, France): new insights and pending questions

Author: Jean-Paul Loreau, Laurent Emmanuel, Benjamin Brigaud, Benoit Vincent, Cambridge Carbonates Ltd, Géosciences Paris Sud ( GEOPS ), Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Study supported by a PhD grant from the ANDRA., Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Biogéosciences [UMR 6282] (BGS), and Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Microprobe, 010504 meteorology & atmospheric sciences, Carbonate, Thin section, δ18O, Stratigraphy, Mineralogy, 010502 geochemistry & geophysics, [ SDU.STU.ST ] Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, 01 natural sciences, Isotopes of oxygen, Diagenesis, chemistry.chemical_compound, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, 0105 earth and related environmental sciences, Calcite, Geology, [ SDU.STU.GC ] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Secondary ion mass spectrometry, chemistry, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Heterogeneity, SIMS
Abstract: 13 pages; International audience; The scope of this work is to investigate, at a high resolution, the oxygen isotope composition (δ18Ocarb) of diagenetic products (synsedimentary and burial calcite cements) in shallow-marine carbonates. SIMS (Secondary Ion Mass Spectrometry) microprobe analyses were performed on thin sections from Oxfordian and Kimmeridgian Formations of the eastern Paris Basin and compared to data obtained on the same diagenetic products by conventional mass spectrometry (acid digestion). Hereby obtained, δ18O are similar, but the SIMS dataset displays a larger range of values.The isotopic zonation obtained by SIMS transects through sequences of cements filling pores, reveals an (expected) isotopic depletion from older stage synsedimentary calcites to younger stage blocky calcites and that follows the CL (cathodoluminescence) zonation. SIMS analyses however show that synsedimentary cements precipitated in intra-skeletal pores, have heavier δ18O than their inter-particle counterparts, with an offset of + 4‰V-PDB, despite similar petrographical characteristics. This difference is maintained in the δ18O of the first stages of blocky calcite cements, intra-skeletal blocky calcites showing heavier δ18O than the time equivalent and petrographically identical inter-particle calcites, with an offset of + 5‰V-PDB. These offsets are tentatively explained by the precipitation of cements under non-equilibrium conditions in intra-skeletal pores, where organic matter decay may have played a key role, acting notably on the pH.The occurrence of isolated micro-diagenetic environments, co-existing at the thin section scale, is tentatively proposed as an explanation to these small scale and high amplitude δ18O heterogeneities. These results may question the sampling strategy for future works. Microdrilling may miss the observed range of variation, but averaging the values may not necessarily lead to real misinterpretations if a critical selection of samples is performed, targeting potentially similar micro-diagenetic environments and avoiding potentially specific ones, i.e. closed intra-skeletal pores.These results also definitely underscore the need for additional experiments to improve the reliability of SIMS, in order to develop the use of this very high resolution technique for carbonate diagenesis studies.
Published: 2017

15. Excursion du GFEJ 2017 dans les Charentes

Author: Colombié , C., Schnyder , Johann, Pellenard , Pierre, Saucède , Thomas, Evolution et Modélisation des Bassins Sédimentaires (EMBS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Laffont, Rémi, Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Evolution et Modélisation des Bassins Sédimentaires ( EMBS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Biogéosciences [Dijon] ( BGS ), and Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS )
Subjects: [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: 1 page; National audience
Published: 2017

16. Late Jurassic dinosaur footprints from Chassiron–La Morelière (Oléron Island, western France)

Author: Didier Néraudeau, Romain Vullo, Johann Schnyder, Bastien Mennecart, Dominique Abit, Jean-David Moreau, Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Géosciences Rennes ( GR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire des Sciences de l'Univers de Rennes ( OSUR ) -Centre National de la Recherche Scientifique ( CNRS ), Naturhistorisches Museum Basel, Evolution et Modélisation des Bassins Sédimentaires ( EMBS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Evolution et Modélisation des Bassins Sédimentaires (EMBS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Association Dinoléron, Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)
Subjects: 010506 paleontology, Dinosaur footprints, Late Jurassic, Context (language use), Trace fossil, Structural basin, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, Paleontology, Oléron Island (France), Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, [ SDU.STU.PG ] Sciences of the Universe [physics]/Earth Sciences/Paleontology, Calcite, Ripple marks, Global and Planetary Change, Ecology, Theropods, Geology, Trackway, White-light scanner, Sauropods, chemistry, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, Tidal flat
Abstract: International audience; A new dinosaur tracksite was recently discovered in the Upper Jurassic deposits from the Oléron Island (Atlantic Ocean, western France). Tracks are located along the coastline in the tidal area of La Morelière near “Pointe de Chassiron”. They were observed in situ in an evaporitic interval from the “Purbeck beds” Unit. Sediments consist of calcite recrystallised after gypsum dissolution within limestone layers which are composed of thin laminites. The track-bearing surface shows abundant mud cracks and some ripple marks. Ichnofossils consist of medium-sized tridactyl footprints of theropods forming a narrow trackway. In order to obtain 3D reconstructions of the track-bearing surface, the trackway was scanned with a resolution of 0.5 mm using an Artec Eva 3D white-light scanner. As indicated by the track dimensions, the probable trackmaker is assigned to a medium-sized non-coelurosaur tetanuran, such as a megalosauroid or an allosauroid theropod. The palaeoenvironmental context is interpreted as a tidal flat in an evaporitic basin. In addition to the tridactyl tracks, we report sauropod- and thyreophoran-like tracks on two other surfaces from Chassiron–La Morelière.
Published: 2017

17. Coda reconstruction from cross-correlation of a diffuse field on thin elastic plates

Author: Philippe Roux, Aida Hejazi Nooghabi, Lapo Boschi, Julien de Rosny, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL), Institut Jean le Rond d'Alembert (DALEMBERT), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ESPCI ParisTech, Institut Jean Le Rond d'Alembert (DALEMBERT), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Institut Jean Le Rond d'Alembert ( DALEMBERT ), Institut des Sciences de la Terre ( ISTerre ), and Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux ( IFSTTAR ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA )
Subjects: Statistics and Probability, Reverberation, noise, causality, Acoustics, FOS: Physical sciences, Physics - Classical Physics, 01 natural sciences, Coda, acoustic, Flexural strength, Robustness (computer science), 0103 physical sciences, [ PHYS.PHYS.PHYS-GEN-PH ] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], surface, correlation function, Diffuse field, 010306 general physics, Dispersion (water waves), Duralumin, 010301 acoustics, Statistical and Nonlinear Physics, Condensed Matter Physics, Physics, [PHYS]Physics [physics], [ PHYS ] Physics [physics], Cross-correlation, Classical Physics (physics.class-ph), mathematical methods, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], aluminum, dispersion
Abstract: International audience; This study contributes to the evaluation of the robustness and accuracy of Green's function reconstruction from cross-correlation of strongly dispersed reverberated signals, with disentangling of the respective roles of ballistic and reverberated (“coda”) contributions. We conduct a suite of experiments on a highly reverberating thin duralumin plate, where an approximately diffuse flexural wave field is generated by taking advantage of the plate reverberation and wave dispersion. A large number of impulsive sources that cover the whole surface of the plate are used to validate ambient-noise theory through comparison of the causal and anticausal (i.e., positive- and negative-time) terms of the cross-correlation to one another and to the directly measured Green's function. To quantify the contribution of the ballistic and coda signals, the cross-correlation integral is defined over different time windows of variable length, and the accuracy of the reconstructed Green's function is studied as a function of the initial and end times of the integral. We show that even cross-correlations measured over limited time windows converge to a significant part of the Green's function. Convergence is achieved over a wide time window, which includes not only direct flexural-wave arrivals, but also the multiply reverberated coda. We propose a model, based on normal-mode analysis, that relates the similarity between the cross-correlation and the Green's function to the statistical properties of the plate. We also determine quantitatively how incoherent noise degrades the estimation of the Green's function.
Published: 2017

18. Importance des variations latérales discrètes dans les apports détritiques, observées dans des faciès de rampe sédimentaire riches en matière organique (Jurassique supérieur du Boulonnais)

Author: François Baudin, Thierry Adatte, Viviane Bout-Roumazeilles, Nicolas Tribovillard, Alain Trentesaux, Ebraheem Hatem, Jean-François Deconinck, Olivier Averbuch, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Evolution et Modélisation des Bassins Sédimentaires (EMBS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences de la terre [Lausanne] (ISTE), Université de Lausanne (UNIL), Support from the CNRS-INSU through the SYSTER program., Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Université de Lausanne = University of Lausanne (UNIL), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 ( LOG ), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique ( CNRS ), Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Evolution et Modélisation des Bassins Sédimentaires ( EMBS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre, Université de Lausanne ( UNIL ), and Université de Lille - Faculté des Sciences et Technologies
Subjects: Kimméridgien-Tithonien, 010504 meteorology & atmospheric sciences, Sulfide, Boulonnais, Geochemistry, Mineralogy, [ SDU.STU.ST ] Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, 010502 geochemistry & geophysics, 01 natural sciences, Kimmeridgian-Tithonian, Sedimentary depositional environment, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, géochimie, Organic matter, roches mères d'hydrocarbure, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, geochemistry, organic matter, chemistry.chemical_classification, minéraux argileux, lcsh:QE1-996.5, Geology, 15. Life on land, Sedimentation, lcsh:Geology, clay minerals, chemistry, Source rock, Clastic rock, matière organique, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, petroleum source rocks, Sedimentary rock, [SDU.OTHER]Sciences of the Universe [physics]/Other, Clay minerals
Abstract: 17 pages; International audience; We studied a potential petroleum source rock deposited in a clastic-dominated ramp environment: the Argiles de Châtillon Formation (Kimmeridgian-Tithonian, Boulonnais area, northern France). The formation was deposited along a proximal-distal gradient on this ramp affected by synsedimentary fault movements. A sedimentological, mineralogical and geochemical study was conducted to decipher the distribution patterns of sedimentary parameters along such a depth increase over the ramp. It comes out that smectite distribution unexpectedly mimics the lateral depth evolution despite the good floatability of the mineral. It is also observed that the Argiles de Châtillon could accumulate noticeable amounts of organic matter in spite of paleoenvironmental conditions that were not specifically prone to organic matter preservation and burial (sedimentation rate, mineral particle grain size, productivity, oxygenation level…). Conversely, reactive iron, when being present in limited abundance, must have allowed sulfide ions to react with organic molecules instead of forming iron sulfides, which fostered organic matter preservation and accumulation. This protecting role of organic sulfide incorporation (additional to other favorable factors) cannot exist if reactive iron is relatively abundant. Lastly, our results (still fragmentary) suggest that smectite minerals could carry reactive iron, which would have occasionally hampered organic-matter preservation.; La formation des Argiles de Châtillon (Kimméridgien-Tithonien, Boulonnais) est un bon analogue géologique de roche mère pétrolière déposée en contexte de rampe clastique. Ces dépôts se sont mis en place le long d'un transect proximal-distal sur une rampe affectée par des mouvements tectoniques synsédimentaires. Pour mettre en évidence et comprendre la distribution des paramètres sédimentaires en fonction de l'évolution de la profondeur, une étude sédimentologique, minéralogique et géochimique fut entreprise. Il en ressort que la distribution de la smectite au sein du cortège argileux respecte ce gradient, malgré la flottabilité reconnue de ce minéral. Il apparaît également que les Argiles de Châtillon ont pu accumuler des quantités sensibles de matière organique malgré un contexte de dépôt peu favorable à la préservation et à l'enfouissement de celle-ci. En revanche, le fer réactif, quand il était présent en faible quantité dans les sédiments, a pu permettre aux ions sulfures de réagir avec les molécules organiques, plutôt que de former des sulfures de fer. Cette sulfuration a pu accroître la résistance de la matière organique à la dégradation microbienne, ce qui explique la bonne préservation du carbone organique. Ce rôle protecteur de la vulcanisation naturelle (qui s'ajoute à d'autres facteurs favorables) ne peut pas s'exercer si le fer réactif est relativement abondant. Nos résultats (encore fragmentaires) suggèrent également que la smectite (qui est un minéral pouvant véhiculer du fer faiblement lié au réseau cristallin) pourrait, dans certains cas, limiter la préservation de la matière organique.
Published: 2017

19. Polyphase ductile/brittle deformation along a major tectonic boundary in an ophiolitic nappe, Alpine Corsica: Insights on subduction zone intermediate-depth asperities

Author: Marc Fournier, Rémi Magott, Olivier Fabbri, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Déformations, sismotectonique, imagerie, relief (DéSIR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Déformations, sismotectonique, imagerie, relief ( DéSIR ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), and Laboratoire Chrono-environnement (UMR 6249) (LCE)
Subjects: Blueschist, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Cataclastic rock, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, Nappe, Metagabbro, Petrology, Mylonite, Peridotite, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, Asperity, geography.geographical_feature_category, Subduction, Geology, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, Shear (geology), Alpine Corsica, Pseudotachylyte, Seismology, Serpentinite
Abstract: International audience; In an ophiolitic nappe of Alpine Corsica, a major fault zone superimposes metagabbro over serpentinite and peridotite. Ductile and brittle deformation structures are observed in the fault damage zones. In the metagabbro damage zone, early deformation culminates in blueschist or eclogite facies conditions and consists of west-verging mylonitization alternating with pseudotachylyte-forming faulting with undetermined vergence. This early deformation is likely coeval with west-verging seismic (pseudotachylyte-forming) reverse faulting in the footwall peridotite or with aseismic distributed cataclastic deformation of footwall serpentinite. These early events (aseismic mylonitization or distributed cataclasis and seismic faulting) are interpreted as reverse faulting/shear in an east-dipping subducting oceanic lithosphere in Cretaceous to Eocene times. Late deformation events consist of ductile shear and seismic faulting having occurred under retrograde greenschist conditions. Kinematics of the ductile shear is top-to-the-east. These events are interpreted as the result of syn-to post-collision extension of Alpine Corsica in Eocene to Miocene times. The heterogeneous distribution of pseudotachylyte veins along the fault zone (abundant at peridotite-metagabbro interfaces, rare or absent at serpentinite-metagabbro interfaces) is interpreted as the consequence of contrasted frictional properties of the rocks in contact. High-friction peridotite-metagabbro contacts could correspond to asperities whereas low-friction serpentinite-metagabbro contacts could correspond to creeping zones.
Published: 2017

20. Unsuspected explosive activity of Montagne Pelée (Lesser Antilles) during the 25–10 ka period

Author: Michaud-Dubuy, Audrey, Carazzo, Guillaume, Balcone-Boissard, Hélène, Boudon, Georges, Kaminski, Edouard, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-16-CE03-0002,RAVEX,Développement d'une approche intégrée pour la réduction des Risques Associés au Volcanisme EXplosif, de la recherche sur l'aléa aux outils de gestion de crise : le cas de la Martinique(2016), and ANR-18-CE03-0010,V-CARE,Sensibilisation précoce aux éruptions volcaniques : Développement, test et étude de l'impact psychosociologique de nouveaux indicateurs en vue d'une meilleure gestion des crises volcaniques.(2018)
Subjects: hazard assessment, Montagne Pelée volcano, eruptive dynamics, Plinian eruption, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, dome-forming eruption, Eruptive history
Abstract: The recent eruptive history of Montagne Pelée volcano was dominated by a period of vigorous basaltic andesitic magma production (36-25 ka) followed by a long period of lower activity (i.e., with less frequent and less voluminous eruptions) and a renewal of felsic magma production in the last 10 ka. The temporal succession of volcanic events that occurred during the 25-10 ka period and the timing of felsic magma production are currently poorly constrained. This study focuses on the stratigraphy and eruptive dynamics of the pyroclastic deposits emplaced immediately after 25 ka. New on-land stratigraphic correlations and radiocarbon dating measurements allow us identifying six major explosive eruptions. We use field data on tephra dispersal, thickness and grain-size distribution together with physical models of explosive volcanic plumes to estimate the eruption source parameters. Our results show that these events are VEI 4 eruptions with intermediate magnitudes (from M = 4.2 to M = 5.1) and intensities (from I = 10.6 to I = 11.6). These eruptions share several characteristics with the most recent Plinian eruptions of Montagne Pelée volcano (i.e., mass eruption rate, maximum column height, runout of pyroclastic density currents, glass composition). The tephra succession documents two phases of magma production rates. The first phase from 25 to 14 ka corresponds to a period of low activity with a magma production rate of 0.04 km3 kyr-1. The second phase from 14 to 10 ka is characterized by a significant increase of the volcanic activity with a magma production rate of 0.4 km3 kyr-1, consistent with previous estimates.
Published: 2023

21. Gas hydrate systems linked to fluid migration within deep-sea fans: results from the SEAGAS project

Author: Praeg, Daniel, Migeon, Sebastien, Ketzer, J.M., Silva, Cleverson, Dos Reis, A.T., Unnithan, Vikram, Augustin, Adolpho, Rodrigues, Luiz Frederico, Pivel, Maria Alejandra Gomez, Machado Cruz, Alberto, Gorini, Christian, Miller, Dennis, Viana, Adriano, Cupertino, José, Pontifical Catholic University of Rio Grande do Sul (PUC-RS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Linnaeus University, Universidade Federal Fluminense [Rio de Janeiro] (UFF), Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro [Rio de Janeiro] (UERJ), Jacobs University [Bremen], Instituto de Geociências, Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Petrobras Research Center, Petrobras EGP-EXP, European Project: 656821,H2020,H2020-MSCA-IF-2014,SEAGAS(2016), Pontifícia Universidade Católica do Rio Grande do Sul [Porto Alegre] (PUCRS), Universidade Federal do Rio Grande do Sul (UFRGS), and Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: [SDU]Sciences of the Universe [physics], flow, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, fluids, failure
Abstract: submitted and accepted; International audience; Fluid migration strongly influences gas hydrate occurrences, increasing concentrations in proportion to gas supply. An upward flow of gas-rich fluids is also central to models proposed to account for the formation of venting features within the gas hydrate stability zone (GHSZ), and for the presence or absence at its based of bottom simulating reflections (BSRs). These models are being tested by the SEAGAS project, an EC-funded collaboration of French and Brazilian research groups, which has examined gas hydrate systems within three deep-sea depocentres : the Nile fan in the Mediterranean Sea, and the Amazon fan and the Rio Grande cone on the Atlantic margin of Brazil. In each depocentre, rapid deposition has driven different forms of gravitational collapse above deep detachments. Each contains a different association of BSRs and venting features. On the Nile fan, a faint BSR of limited extent (3000 km 2 , water depths 2000-2500 m) contrasts with more widespread evidence of gas hydrates (in well logs) and fluid vents (pockmarks, mud volcanoes); the relation to pre-and post-Messinian collapse structures is unclear. On the Amazon fan, elongate BSR patches (total area 6700 km 2 , water depths 750-2250 m) coincide with the crests of an arcuate thrust-fold belt on the upper fan, which host mud volcanoes and other seafloor vents; no BSR is observed below the collapse belt on the mid-to lower fan. On the Rio Grande cone, a regional BSR (45,000 km 2 , water depths 500-3500 m) spans paired extensional and compressive belts, the former including fault-controlled fluid vents (pockmarks). In each area, BSR inversion yields temperature gradients elevated up to 5 times background values via long-wavelength (10 0-10 1 km) variations that, on the Brazilian margin, follow structural trends. We argue that these observations can be explained in terms of tectonic-and/or compaction-driven variations in the upward flow of warm fluids containing dissolved and/or free gas, which control the formation (or not) of BSRs and, in places, of gas vents. We hypothesise that temporal variations in fluid flow will change GHSZ thickness from below; bottom-up thinning will release gas and water from hydrate-rich sediments, potentially destabilising large volumes of slope sediments. This hypothesis could account for the occurrence of landslides on depocentres with low seafloor gradients (
Published: 2023

22. Tracking timescales of magma reservoir recharge through caldera cycles at Santorini (Greece). Emphasis on an explosive eruption of Kameni Volcano

Author: Polo-Sánchez, Antonio, Flaherty, Taya, Hervé, Garance, Druitt, Tim, Fabbro, Gareth, Nomikou, Paraskevi, Balcone-Boissard, Helène, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Departamento de Geología [Salamanca], Universidad de Salamanca, School of Environmental Sciences [Norwich], University of East Anglia [Norwich] (UEA), Department of Geology and Geoenvironment, National and Kapodistrian University of Athens (NKUA), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), and ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016)
Subjects: caldera cycles, pyroxene, Santorini, diffusion timescales, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, diffusion timescales Kameni Santorini caldera cycles pyroxene, Kameni
Abstract: Pre-eruptive processes and their timescales are critical information for risk management at explosive volcanoes, and Santorini caldera (Greece) provides an excellent context in which to approach this subject. We ask two questions. First, are pre-eruptive processes the same for small and big eruptions? To investigate, we performed a multi-mineral diffusion timescale study of a small explosive eruption of Kameni Volcano and compared the results with those published for larger caldera-forming eruptions at Santorini. The Kameni dacite resembles products of larger eruptions in being crystal-poor, containing plagioclase with antecrystic cores and autocrystic rims, bearing orthopyroxene with sector zoning and phantom skeletal morphologies, and showing evidence for mixing of different silicic magmas prior to eruption. Diffusion timescales from Mg-Fe profiles in orthopyroxene and clinopyroxene phenocrysts are
Published: 2023

23. Gauging scale effects and biogeographical signals in similarity distance decay analyses: an Early Jurassic ammonite case study

Author: Jean-Louis Dommergues, Axelle Zacaï, Rémi Laffont, Emmanuel Fara, Arnaud Brayard, Bruno Vrielynck, Gilles Escarguel, Christian Meister, Biogéosciences [Dijon] ( BGS ), AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Département de Géologie et de Paléontologie, Muséum d'Histoire Naturelle de Genève, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés ( LEHNA ), Institut National de la Recherche Agronomique ( INRA ) -Centre National de la Recherche Scientifique ( CNRS ) -École Nationale des Travaux Publics de l'État ( ENTPE ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon, Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Study partly supported by the Fondation pour la Recherche sur la Biodiversité (FRB)., Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] (BGS), and Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010506 paleontology, Biogeography, scale effects, Context (language use), Biology, 010603 evolutionary biology, 01 natural sciences, [ SDE ] Environmental Sciences, Paleontology, Similarity (network science), Geographical distance, provincialism, Ecology, Evolution, Behavior and Systematics, biogeography, 0105 earth and related environmental sciences, [ SDU.STU.PG ] Sciences of the Universe [physics]/Earth Sciences/Paleontology, Ammonite, ammonites, Phylogenetic tree, Pliensbachian, language.human_language, Taxon, similarity distance decay, [SDE]Environmental Sciences, language, Biological dispersal, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
Abstract: 17 pages; International audience; In biogeography, the similarity distance decay (SDD) relationship refers to the decrease in compositional similarity between communities with geographical distance. Although representing one of the most widely used relationships in biogeography, a review of the literature reveals that: (1) SDD is influenced by both spatial extent and sample size; (2) the potential effect of the phylogenetic level has yet to be tested; (3) the effect of a marked biogeographical structuring upon SDD patterns is largely unknown; and (4) the SDD relationship is usually explored with modern, mainly terrestrial organisms, whereas fossil taxa are seldom used in that perspective. Using this relationship, we explore the long-distance dispersal of the Early Jurassic (early Pliensbachian, c. 190.8 Ma to 187.6 Ma) ammonites of the western Tethys and adjacent areas, in a context of marked provincialism. We show that the long-distance dispersal of these ammonites is not related to shell size and shape, but rather to the environmental characteristics of the province to which they belong. This suggests that their long-distance dispersal may have been essentially driven by passive planktonic drift during early juvenile, post-hatching stages. Furthermore, it seems that the SDD relationship is not always an appropriate method to characterize the existence of a biogeographical structuring. We conducted SDD analyses at various spatial, sampling and phylogenetic scales in order to evaluate their sensitivity to scale effects. This multi-scale approach indicates that the sampling scale may influence SDD rates in an unpredictable way and that the phylogenetic level has a major impact on SDD patterns.
Published: 2016

24. Impact of gneissic layering and localized incipient melting upon melt flow during experimental deformation of migmatites

Author: A.C. Ganzhorn, P. Trap, L. Arbaret, R. Champallier, J. Fauconnier, L. Labrousse, G. Prouteau, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), European Project: 290864,EC:FP7:ERC,ERC-2011-ADG_20110209,RHEOLITH(2012), Institut des Sciences de la Terre d'Orléans - UMR7327 ( ISTO ), Bureau de Recherches Géologiques et Minières (BRGM) ( BRGM ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), European Project : 290864,EC:FP7:ERC,ERC-2011-ADG_20110209,RHEOLITH ( 2012 ), Magma - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)
Subjects: 010504 meteorology & atmospheric sciences, Muscovite, Mineralogy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, anisotropy, Deformation (meteorology), engineering.material, 010502 geochemistry & geophysics, Migmatite, 01 natural sciences, pure-shear deformation, [SDU]Sciences of the Universe [physics], engineering, natural gneiss, Layering, Shear zone, Quartz, [ SDU ] Sciences of the Universe [physics], 0105 earth and related environmental sciences, Melt flow index, Gneiss, partially molten
Abstract: International audience; In this study, we test experimentally the role of compositional layering as a key parameter for controlling melt flow in a natural migmatite during coaxial deformation. We performed in – situ pure-shear experiments on two natural gneisses. The first gneiss is weakly foliated with minerals homogenously distributed. The second gneiss shows a pronounced compositional layering of alternating quartz – feldspar – rich and biotite – muscovite – rich layers. Experimental conditions were selected to obtain homogeneous melt distribution in the homogeneous gneiss and heterogeneous melt distribution in the layered gneiss. Initial melt distribution is not modified by deformation in experiments on the homogeneous gneiss, implying that melting products did not migrate from their initiation sites. In contrast, melt flowed in shear zones or in inter-boudin positions during experimental deformation of the heterogeneous gneiss. These experiments attest to the strong influence of initial gneissic layering on melting pattern, melt segregation and flow during deformation of partially molten rocks.
Published: 2016

25. Reactive transport modelling of carbonate cementation in a deep saline aquifer, the Middle Jurassic Oolithe Blanche Formation, Paris Basin, France

Author: Fabien Aubertin, Sophie Violette, Yasin Makhloufi, Remi Charton, Pierre Yves Collin, Vincent Lagneau, Françoise Bergerat, Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Biogéosciences [UMR 6282] [Dijon] (BGS), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Centre de Géosciences (GEOSCIENCES), MINES ParisTech - École nationale supérieure des mines de Paris, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Work partly funded by the CNRS INSU-CESUR project and supported by the French Geological Survey (BRGM, ‘‘Bureau de recherches géologiques et minières’’, Orléans, France)., Laboratoire de géologie de l'ENS ( LGE ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Département des Géosciences - ENS Paris, École normale supérieure - Paris ( ENS Paris ) -École normale supérieure - Paris ( ENS Paris ), Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Centre de Géosciences ( GEOSCIENCES ), MINES ParisTech - École nationale supérieure des mines de Paris-PSL Research University ( PSL ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), and Mines Paris - PSL (École nationale supérieure des mines de Paris)
Subjects: 010504 meteorology & atmospheric sciences, Geochemistry, Palaeo-circulations, Carbonates, Earth and Planetary Sciences(all), Structural basin, 010502 geochemistry & geophysics, [ SDU.STU.ST ] Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, 01 natural sciences, Permeability, Diagenesis, chemistry.chemical_compound, Numerical simulations, Geomorphology, 0105 earth and related environmental sciences, Global and Planetary Change, Hydrogeology, Groundwater recharge, Cementation (geology), 6. Clean water, Permeability (earth sciences), chemistry, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Meteoric water, General Earth and Planetary Sciences, Carbonate, Porosity, Geology
Abstract: 10 pages; International audience; The Oolithe Blanche Formation (Bathonian, Middle Jurassic) is one of the deep saline aquifers of the Paris Basin in France. The spatial distribution of its reservoir properties (porosity, permeability, tortuosity, etc.) is now better known with relatively homogeneous properties, except for some levels in the central part of the basin, where permeability exhibits higher values. This spatial distribution has been correlated with diagenetic events (variability of cementation) and palaeo-fluid flow circulation phases leading to variable cementation. In this paper, numerical simulations of reactive transport are performed. They provide a preliminary quantitative analysis of the Oolithe Blanche Formation, the type of fluids involved, the duration of fluid flow, and the time required to reduce the primary porosity of the Bathonian sediments by 10% due to cementation. Our results from the reactive transport simulations along a flow line, and a parameter sensitivity analysis suggest that diagenesis processes driven by meteoric water recharge do not exclusively cause the 10% decrease in porosity. Other geochemical and hydrogeologic processes must be involved.
Published: 2016

26. Subduction zone intermediate-depth seismicity: Insights from the structural analysis of Alpine high-pressure ophiolite-hosted pseudotachylyte (Corsica, France)

Author: Rémi Magott, Marc Fournier, Olivier Fabbri, Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire Chrono-environnement (UMR 6249) (LCE)
Subjects: Blueschist, 010504 meteorology & atmospheric sciences, Intermediate-depth seismicity, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Fault (geology), 010502 geochemistry & geophysics, Ophiolite, 01 natural sciences, Metagabbro, Petrology, Peridotite, Metamorphic facies, 0105 earth and related environmental sciences, geography, Cataclasite, geography.geographical_feature_category, Geology, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, Subduction, Alpine Corsica, Pseudotachylyte, Eclogite, Seismology, Mylonite
Abstract: International audience; Pseudotachylyte in the Cima di Gratera ophiolite, Alpine Corsica, is distributed in the peridotite unit and in the overlying metagabbro unit and was formed under blueschist to eclogite metamorphic facies conditions, corresponding to a 60–90 km depth range. Peridotite pseudotachylyte is clustered in fault zones either beneath the tectonic contact with overlying metagabbros or at short distance from it. Fault zones are either parallel to the contact or make an angle of 55° to it. Displacement sense criteria associated with fault veins indicate top-to-the-west or top-to-the-northwest reverse senses. Cataclasite flanking most veins was formed before or coevally with frictional melting and likely mechanically weakened the peridotite, facilitating subsequent seismic rupture. In the basal part of the metagabbro unit, post-mylonitization pseudotachylyte can be distinguished from pre-mylonitization pseudotachylyte formed earlier. In the equant metagabbro above the mylonitic sole, only one episode of pseudotachylyte formation can be identified. Kinematics associated with metagabbro pseudotachylyte remain unknown. The geometry and kinematics of the pseudotachylyte veins from the peridotite unit and to a lesser extent from the metagabbro unit are similar to modern seismic ruptures of the upper parts of the Wadati-Benioff zones such as in the Pacific plate beneath NE Japan.
Published: 2016

27. Chalky versus foliated: a discriminant immunogold labelling of shell microstructures in the edible oyster Crassostrea gigas

Author: Nathalie Guichard, Franck Lartaud, Vincent Mouchi, Marc de Rafélis, Frédéric Marin, Cédric Broussard, Françoise Immel, Quentin Crowley, School of Natural Sciences, Trinity College Dublin, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Laboratoire SUBATECH Nantes (SUBATECH), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), Laboratoire de biogenèse membranaire (LBM), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut Cochin (IC UM3 (UMR 8104 / U1016)), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), HAL-UPMC, Gestionnaire, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Ecogéochimie des environnements benthiques ( LECOB ), Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ), Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire SUBATECH Nantes ( SUBATECH ), Mines Nantes ( Mines Nantes ) -Université de Nantes ( UN ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de biogenèse membranaire ( LBM ), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique ( CNRS ), Géosciences Environnement Toulouse ( GET ), Institut de Recherche pour le Développement ( IRD ) -Université Toulouse III - Paul Sabatier ( UPS ), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Institut Cochin ( UM3 (UMR 8104 / U1016) ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ), AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), and Institut de Recherche pour le Développement ( IRD ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: 0301 basic medicine, 010506 paleontology, Oyster, [ SDV.BA.ZI ] Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, Mineralogy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Aquatic Science, 01 natural sciences, 03 medical and health sciences, chemistry.chemical_compound, Labelling, biology.animal, Mantle (mollusc), Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Calcite, Ecology, biology, Differential staining, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, Immunogold labelling, biology.organism_classification, Microstructure, [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, 030104 developmental biology, chemistry, Biophysics, [SDV.BA.ZI] Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, Crassostrea
Abstract: International audience; Mollusc shells are organic–inorganic biocomposites, arranged in a limited number of superimposed calcified layers that generally exhibit very different organization of their crystallites. Because of their attractive mechanical and crystallographic properties, these shell layers have been the focus of several physical and biochemical characterizations. In particular, recent proteomic data obtained from individual layers suggest that their protein contents are different. However, the direct visual evidence that some macromolecular components are layer-specific is rather tenuous. This paper is based on a non-conventional immunogold labelling approach to localize proteins in the shell of the edible oyster Crassostrea gigas. The shell microstructure of this model organism is predominantly composed of foliated calcite, interspersed by discontinuous pockets of ‘chalky layers’, a porous microstructure typical of bivalves of the ostreid family. By developing a polyclonal antibody (in two rats) elicited against a proteinaceous shell fraction, we obtained differential staining of the two microstructures. We assert that our labelling is microstructure discriminant. The difference in labelling of the two shell microstructures suggests either that they are formed by a variation of the secretory repertoire of the shell-forming cells of the calcifying mantle epithelium or that the chalky layer may be formed via a completely different mechanism. Our results allow a first glimpse on the subtle regulatory mechanisms that drive the process of chalky and foliated layers deposition.
Published: 2016

28. Bioenergetic control of soil carbon dynamics across depth

Author: Ludovic Henneron, Jerôme Balesdent, Gaël Alvarez, Pierre Barré, François Baudin, Isabelle Basile-Doelsch, Lauric Cécillon, Alejandro Fernandez-Martinez, Christine Hatté, Sébastien Fontaine, Etude et Compréhension de la biodiversité (ECODIV), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU), Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Soil, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Multidisciplinary, Rhizosphere, General Physics and Astronomy, Agriculture, General Chemistry, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Carbon, Soil Microbiology, General Biochemistry, Genetics and Molecular Biology, Carbon Cycle
Abstract: Soil carbon dynamics is strongly controlled by depth globally, with increasingly slow dynamics found at depth. The mechanistic basis remains however controversial, limiting our ability to predict carbon cycle-climate feedbacks. Combining radiocarbon and thermal analyses with long-term incubations in absence/presence of continuously 13C/14C-labelled plants, we show here that bioenergetic constraints of decomposers consistently drive the depth-dependency of soil carbon dynamics over a range of mineral reactivity contexts. The slow dynamics of subsoil carbon was tightly related to both its low energy density and high activation energy of decomposition, leading to an unfavorable ‘return-on-energy-investment’ for decomposers. We also observed strong acceleration of millennia-old subsoil carbon decomposition induced by roots (‘rhizosphere priming’), showing that sufficient supply of energy by roots is able to alleviate the strong energy limitation of decomposition. These findings demonstrate that subsoil carbon persistence results from its poor energy quality together with the lack of energy supply by roots due to their low density at depth. These findings provide insights into the bioenergetic control of SOC persistence and indicate that an increase in plant rooting depth induced by global change could threaten the storage of millennia-old SOC in deep layers.
Published: 2023

29. First archive of extensive N-fixation by volcanic lightning and implications for the prebiotic Earth

Author: Adeline Aroskay, Erwan Martin, Slimane Bekki, Joël Savarino, Jean-Luc Le Pennec, Abidin Temel, Nelida Manrique, Rigoberto Aguilar, Marco Rivera, Sophie Szopa, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Hacettepe University = Hacettepe Üniversitesi, Instituto Geológico Minero y Metalúrgico (INGEMMET), Instituto Geofísico del Perú (IGP), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology
Abstract: On Earth, most of the nitrogen (N) accessible for life is trapped in dinitrogen (N2), which is the most stable atmospheric molecule. In order to be metabolised by living organisms, N2 has to be converted into assimilable forms, also called fixed N. Nowadays, nearly all the N-fixation is achieved through biological and anthropogenic processes. However, in early environments of the Earth, before the emergence of life, N-fixation must have occurred via natural abiotic processes. Electrical discharges, including from thunderstorms and also lightning associated with volcanic eruptions is one of the most invoked processes. The occurence of volcanic lightning during explosive eruptions is frequent, and convincing laboratory experimentations support the role of this phenomenon, however no evidence of substantial N-fixation has been found in volcanic records. Here we report on the discovery of large amounts of nitrates in volcanic deposits from Neogene caldera-forming eruptions, which are well correlated with the concentrations of species directly emitted by volcanoes such as sulphur and chlorine. The multi-isotopic composition (δ18O, Δ17O) of the nitrates reveals that they originate from the atmospheric oxidation of nitrogen oxides formed by volcanic lightning that occur during the eruption. According to these volcanic nitrate records, our first estimates suggest that about 60 Tg of N can be fixed during a large explosive event. Our findings hint at a unique role potentially played by subaerial explosive eruptions in supplying essential ingredients for the emergence of life on Earth.
Published: 2023

30. Integrated Source to Sink palaeogeological maps at pluri-basins-scale, understandings and predictions

Author: Eric Lasseur, Alexandre Ortiz, Charlotte Fillon, Justine Briais, Francois Guillocheau, Jessica Uzel, Gianlucca Frasca, Jocelyn barbarand, Nicolas Loget, Sebastien Castellort, Sylvain Calassou, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), TotalEnergies, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), institute of geosciences and earth ressource, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Genève = University of Geneva (UNIGE), and European Geosciences Union
Subjects: [SDE]Environmental Sciences
Abstract: International audience; The knowledge acquired on the exhumation of the Pyrenean chain and the evolution of the adjacent foreland basins makes this Alpine-type domain a good laboratory to better constrain a full sediment routing system in a compressive context and to apprehend the driving processes controlling the sediment routing in space and time. This integrated approach aims at enhancing our basin mastering approach as well as improving our predictions of reservoir properties. This Source-to-Sink study seeks to understand the evolution of sedimentary routing from the Source (orogenic relief, craton, basin recycling) through the transfer zone (peripheral or internal to the basin) to the final sink (flexural basin, deep turbiditic margin). Within this new cartography, we propose to compile the data over the entire peri-Pyrenean domain. We produced large scale quantitative and qualitative maps to better observe and interpret the tectonic, climatic and surface processes impacts of the SRS behavior. These maps include kinematic reconstructions of the Iberian-European-Mediterranean system, restored sequential cross-sections, history/magnitude of exhumation by thermochronology, source tracking, characterization of weathering and erosion surfaces, synthesis of the major structures activity, paleogeographic reconstructions, analysis of sedimentary geometries and transport directions as well as the quantification of volumes preserved in the basins. Their interpretation is combined with a time representation along the routing system, linking classical basin wheeler diagram representation to source erosion and lithologies to obtain a continuous view on the sediment journey. The time steps chosen for these 5 maps account for the different stages of tectono-sedimentary evolution of the peri-Pyrenean system at the early-, syn- and post-orogenic stages. The compilations carried out compare exhumed domains and sedimentation zones in terms of fluxes and volumes and make it possible to map the routing systems and point out the main drivers for the surface evolution during the construction/destruction cycle of an orogen. Research work financed and carried out as part of the BRGM-TOTAL Source-to-Sink program
Published: 2023

31. Astrochronology of the Aptian stage and evidence for the chaotic orbital motion of Mercury

Author: Guillaume Charbonnier, Slah Boulila, Jorge E. Spangenberg, Jean Vermeulen, Bruno Galbrun, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Dynamiques de la Surface Terrestre [Lausanne] (IDYST), Université de Lausanne = University of Lausanne (UNIL), n.a., particulier, ERC AstroGeo, and ANR-19-CE31-0002,AstroMeso,Solution astronomique pour le Mésozoïque(2019)
Subjects: Vocontian Basin, Geophysics, Space and Planetary Science, Geochemistry and Petrology, astrochronology, Earth and Planetary Sciences (miscellaneous), Aptian, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Mercury, OAEs, astronomical chaos
Abstract: International audience; The Aptian stage, between ∼113 and ∼121 million years ago (Ma), was punctuated by a succession of Oceanic Anoxic Events (OAEs), recording extreme global warmings, dramatic expansions of the ocean's oxygen minimum zones, along with perturbations to the biotic and carbon cycles. However, the chronology of the Aptian stage is poorly constrained, impacting the duration and timing of OAEs. Using a greatly expanded sedimentary composite record (380 m) of key outcropping sections in the Vocontian Basin (SE France) combined with available radiometric dates and correlations to a set of astronomical solutions, we provide a constrained absolute astrochronology of the Aptian stage. The 405 kyr (gVenus–gJupiter) eccentricity astronomical timescale indicates a minimal duration of ∼9.4 Myr for the Aptian stage and an age of 122.6 ± 0.3 Ma for the base of the Aptian, consistent with radioisotope dating. We find a deviation in the periodicity of gMercury–gJupiter eccentricity term in the mid-Aptian stage, at ca. 117.19 ± 0.3 Ma, that we ascribe as an expression of the resonance transition σ = (gMercury – gJupiter) – (sMercury – sVenus), in relation with a strong chaotic orbital motion of Mercury. Such a geological observation is supported by a concomitant resonant transition in the La2004 astronomical model.
Published: 2023

32. A systematic study of mantle drag effect on subduction dynamics and overriding plate deformation

Author: Thomas Geffroy, Guillaume Benjamin, Replumaz Anne, Simoes Martine, Lacassin Robin, Kermarrec Jean-Jacques, Habel Tania, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPG Paris), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and European Geosciences Union
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
Abstract: International audience; Plates and the convective mantle interact with each other over geological time scales, leading to mantle flow, plate motion, and deformation along plate boundaries. At convergent boundaries undergoing subduction, the role played by mantle drag remains poorly understood despite its potential impact on subduction dynamics, and in turn on the deformation regime of the overriding plate. Previous studies were generally conducted in two dimensions, limiting their ability to faithfully reproduce processes taking place on Earth. Instead, in this study, we present 11 three-dimensional analog models of subduction at the scale of the upper mantle, including an overriding plate, and in which we control mantle drag at the base of the lower or upper plate by imposing a controlled unidirectional background mantle flow perpendicular to the trench. We systematically vary the velocity and the direction of the imposed horizontal mantle flow and quantify its impact on horizontal and vertical upper plate deformations, plate and subduction velocities, and the geometry of the slab. The geometry of the slab is only marginally affected by the velocity and direction of the mantle flow. In the absence of mantle flow, slab rolls back and deformation is accommodated by trench-orthogonal stretching in the upper plate. Instead, the addition of a background flow dragging the lower or upper plate toward the trench systematically results either in the absence of upper plate deformation, or in trench-orthogonal shortening with strain rates that increase linearly with increasing mantle flow. We show that the upper plate strain rate is primarily controlled by the velocity of the free plate in the model, which itself results from the drag exerted by the mantle at the base of the plate. Coupling between mantle and plate is larger for models with flow directed toward the upper plate, resulting in strain rates that are about three times larger than for equivalent models with flow directed toward the lower plate. This systematic study provides a better understanding of the effect of mantle drag on plate displacements and deformation along subduction zones, leading to a better understanding of the ingredients required to form Andean-type mountain ranges.
Published: 2023

33. Developing a robust biogeochemical framework of the coccolith vital effects for more reliable paleoclimatic reconstructions

Author: Goulwen Le Guevel, Fabrice Minoletti, Carla Geisen, Michael Hermoso, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Université du Littoral Côte d'Opale (ULCO), TOPCAPI - INSU TELLUS SYSTER, and ANR-17-CE01-0004,CARCLIM,Les coccolithophoridés : acteurs et enregistreurs des changements climatiques(2017)
Subjects: biogéochimie, Effets vitaux, Paléoclimat, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Coccolithes, CO2
Abstract: The major climatic forcing parameters on Earth climate are temperature and the atmospheric concentrations of CO2. Even if their evolutions covaried to the first-order, the geological record show periods with non-linear evolution between those two parameters. Such delinking requires accurate paleoclimate reconstructions with implications for the modelling studies of our future climate.pCO2 and Sea Surface Temperature (SST) reconstructions are usually quantified using proxies relying on both the organic matter produced by coccolithophores (UK37’ index and δ13Calkenones) and calcite of foraminiferal tests (δ11B, δ18O, Mg/Ca). These proxies have been very useful for a variety of paleoclimatic advances, yet present unresolved and potentially important biases. As an example, alkenone carbon isotopes are not able to register low to moderate pCO2 levels (Badger et al., 2019). This is notoriously a major issue for paleoclimate reconstructions of the last 6 My (Plio-Pleistocene period).Our approach is to use a unique archive – the coccoliths – for determination of coeval SST and pCO2. Coccoliths are small calcite plates produced by unicellular photosynthetic algae called coccolithophores. They are a very promising substrate to analyse for paleoclimate studies because they calcify in the uppermost water column and because their isotopic ratios are sensitive to both photosynthesis and calcification (Hermoso et al. 2020). Therefore, these isotopic ratios provide physiological and metabolic information about coccolithophores of the past. In order to infer paleoclimates from the sedimentary archives, we have to deconvolve the isotopic biological imprint (vital effect) from the environment signal. For the evaluation of the vital effects, we have undertaken a large-scaled culture experiments with various strains of coccolithophore grown under various CO2 concentrations and pH (Le Guevel et al. in prep). Even if we have managed culture until 1400ppm and 7.55 unit of pH, we were particularly interested in low pCO2 and high pH conditions because the bibliography is lacking of vital effect for Plio-Pleistocène applications. All the selected strains produce coccoliths within the size range of the one we find predominantly in the marine sediments throughout geological times.We document a large decrease of the carbon differential vital effect with the CO2 concentration increase between Gephyrocapsa oceanica and Coccolithus braarudii. This is consistent with previous studies but the absolute values are slightly different and we provide a more precise dataset at low to moderate pCO2 than the previous ones (Rickaby et al., 2010; Hermoso et al., 2016). We propose the first study of the oxygen and carbon vital effect of the Helicosphaera carteri group with combined CO2/pH changes. Taken together, the culture data and measurements of the isotopic composition of the calcite biominerals allows better paleoreconstructions of SST and aqueous CO2.
Published: 2023

34. Using detrital thermochronology on moraine deposits to infer glacial erosion patterns and rock thermal history : insights from the Arve and Maurienne valleys (Western European Alps)

Author: Benjamin Guillaume, Nathan Cogné, Kerry Gallagher, Pierre G. Valla, Christian Crouzet, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and European Geosciences Union
Subjects: [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry
Abstract: International audience; This study tests the application of combined detrital apatite fission track (AFT) and U-Pb dating to infer both glacial erosion spatial patterns and long-term rock cooling histories in Alpine mountainous settings. We have dated 716 detrital apatite grains from glacial sediments collected in the Maurienne and Arve valleys (Western European Alps, France) from moraine deposits corresponding to different stages of glacial retreat since the Last Glacial Maximum (LGM, ca. 24-21 ka).The Maurienne valley crosses the internal and external Alps, which exhibit contrasting in-situ AFT and U-Pb ages. Here, we present the measured distribution of both detrital AFT and U-Pb ages at 6 locations along the valley, with catchment elevations ranging from 390 to 1740 m. We show that during glacial retreat, erosion is mainly concentrated in the downstream part of the glacier, near the sampled moraine deposits. This inference suggests that during glacial retreat, glacial erosion is more effective below the ELA (Equilibrium Line Altitude) and specifically close to the glacier front, in areas where ice flow velocity is high and subglacial water is abundant, as predicted by ice-dynamics reconstructions in the European Alps over the last 20 ka.In the Arve valley, previous studies showed that in situ AFT ages are systematically younger than 7 Ma for the Mont-Blanc massif. We compare the thermal history obtained from these literature bedrock-derived data to that derived from the new detrital AFT data collected in the Little Ice Age (LIA) moraine, just at the front of the Bossons glacier (~1300 m elevation). We also compare our results with 5 other samples down the valley at catchment elevations between 460 and 1050 m to evaluate potential changes in the detrital AFT signal as well as the consistency in the retrieved long-term cooling history.Based on these first results, we plan to extend our study to other areas (e.g., Patagonia) to investigate both (1) spatial patterns of glacial erosion for older glacial periods (pre-LGM), and (2) long-term rock cooling histories from moraine deposits where modern bedrock is inaccessible (e.g. under modern glaciers or ice fields).
Published: 2023

35. Subobduction: subduction plate boundary hiccups revealed by blueschists, eclogites and ophiolites

Author: Philippe Agard, Mathieu Soret, Guillaume Bonnet, Dia Ninkabou, Alexis Plunder, Cécile Prigent, Philippe Yamato, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), and European Geosciences Union
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
Abstract: Fragments of ancient oceanic lithosphere preserved in mountain belts, though volumetrically subordinate, provide essential insights into past geodynamics and formation and destruction of oceanic lithosphere. This contribution shows how the two types of oceanic fragments, blueschists and eclogites, on one hand, and ophiolites on the other, preserve crucial information on the dynamics of oceanic convergence, i.e. subduction and obduction.Their mutual relationships, as well as the similarities and differences in the mechanisms leading to their preservation, allow tracking the evolution of the subduction process through time, from the onset of intra-oceanic subduction to the cessation of continental subduction – and, in some cases, to the obduction of ophiolites.Fragments located at the base and immediately below unmetamorphosed (true) ophiolites represent witnesses of intra-oceanic subduction initiation and reveal, in particular, initial mechanical resistance to subduction, subsequent cooling and gradual strain localization. Subducted fragments of oceanic lithosphere metamorphosed as blueschists and eclogites, scraped off the downgoing slab episodically, at shallow or great depths, provide direct access to the composition, structure and rheology of rocks at the plate interface.Both types reflect the mechanical behavior and 'hiccups' of the subduction plate boundary, during subduction initiation and mature subduction respectively.
Published: 2023

36. Upper-plate shortening and Andean-type mountain-building in the context of mantle-driven oceanic subduction

Author: Robin Lacassin, Tania Habel, Anne Replumaz, Benjamin Guillaume, Martine Simoes, Thomas Geffroy, Jean-Jacques Kermarrec, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPG Paris), and European geosciences Union
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
Abstract: To explore the conditions that lead to mountain-building in the case of an oceanic subduction, we conduct analog experiments (with silicon putty upper and lower plates, glucose syrup upper mantle) where subduction is driven by slab pull but also by an underlying mantle flow. Here, plate displacement is not imposed as in most models, but is controlled by the overall balance of forces in the system. We simulate three scenarios: no mantle flow (slab-pull driven subduction), mantle flow directed toward the subducting plate, and mantle flow directed toward the overriding plate. In the case of this latter scenario, we also test the influence of pre-existing rheological contrasts in the upper plate to best reproduce natural cases where inheritance is common. Our experiments show that when plate convergence is also driven by a background mantle flow, the continental plate deforms with significant trench-orthogonal shortening (up to 30% after 60 Myr), generally associated with thickening. We further identify that upper plate shortening and thickening is best promoted when the mantle flow is directed toward the fixed overriding continental plate. The strength of the upper plate is also a key factor controlling the amount and rates of accommodated shortening. Deformation rates increase linearly with decreasing bulk strength of the upper plate, and deformation is mostly localized where viscosity and strength are lower. When compared to the particular natural case of the Andes, our experiments provide key insights into the geodynamic conditions that lead to the building of this Cordilleran orogen since the Late Cretaceous - Early Cenozoic.
Published: 2023

37. La pierre à Delphes : matériaux et carrières (2021)

Author: Amélie Perrier, Marilou de Vals, Isabelle Moretti, Luigi Piccardi, Tommy Vettor, IRAMAT - Centre Ernest Babelon (IRAMAT-CEB), Institut de Recherche sur les Archéomatériaux (IRAMAT), Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CNR Istituto di Geoscienze e Georisorse (IGG ), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Muséum national d'Histoire naturelle (MNHN), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), and Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDE]Environmental Sciences, General Earth and Planetary Sciences, General Environmental Science
Abstract: International audience
Published: 2023

38. The Norfolk Ridge: A Proximal Record of the Tonga‐Kermadec Subduction Initiation

Author: J. Collot, R. Sutherland, S. Etienne, M. Patriat, W. R. Roest, B. Marcaillou, C. Clerc, W. Stratford, N. Mortimer, C. Juan, A. Bordenave, P. Schnurle, D. Barker, S. Williams, S. Wolf, M. Crundwell, Service Géologique de Nouvelle Calédonie, Geological Survey of New Caledonia, Department of Industry Mines and Energy-Department of Industry Mines and Energy, Victoria University of Wellington, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), GNS Science [Lower Hutt], GNS Science, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Douglas Mental Health University Institute [Montréal], McGill University = Université McGill [Montréal, Canada], Institut national des sciences de l'Univers (INSU - CNRS), DIMENC/SGNC (SGNC), Institut des Sciences de la Terre de Paris (iSTeP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Geophysics, [SDU]Sciences of the Universe [physics], Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract: Norfolk Ridge bounds the northeastern edge of the continent of Zealandia and is proximal to where Cenozoic Tonga-Kermadec subduction initiation occurred. We present and analyze new seismic reflection, bathymetric and rock data from Norfolk Ridge that show it is composed of a thick sedimentary succession and that it was formed and acquired its present-day ridge physiography and architecture during Eocene to Oligocene uplift, emergence and erosion. Contemporaneous subsidence of the adjacent New Caledonia Trough shaped the western slope of Norfolk Ridge and was accompanied by volcanism. Neogene extension along the eastern slope of Norfolk Ridge led to the opening of the Norfolk Basin. Our observations reveal little or no contractional deformation, in contrast to observations elsewhere in Zealandia, and are hence significant for understanding the mechanics of subduction initiation. We suggest that subduction nucleated north of Norfolk Ridge and propagated rapidly along the ridge during the period 40-35 Ma, giving it a linear and narrow shape. Slab roll-back following subduction initiation may have preserved the ridge and created its eastern flank. Our observations suggest that pre-existing structures, which were likely inherited from Cretaceous Gondwana subduction, were well-oriented to propagate rupture and create self-sustaining subduction. Key Points We present new marine geophysical and geological data of Norfolk Ridge located along the northeastern edge of the Zealandia continent We show that the ridge is not inherited from Cretaceous rifting that led to isolation of Zealandia but from the TECTA Cenozoic tectonic event Analysis of the structure and evolution of Norfolk Ridge underpins our understanding of tectonic processes of subduction initiation Plain Language Summary Plate tectonic theory established and proved that the surface of Earth is composed of rigid moving plates, but it remains unclear how and why these plates sometimes re-configure their boundaries and motions. Subduction zones are places where two plates converge and one plunges deep into the Earth beneath the other one. As the plate sinks, it drags the rest of the plate with it and acts as an engine that “pulls” the plate and drives horizontal motion. This is what drives the dynamics of plate tectonics. How are subduction zones created? This remains an open question, but we know from geological observations that new subduction zones do get created: more than half of all active subduction zones were created after the dinosaurs died out 65 million years ago. We present new observations from northern Zealandia (a submerged continent between New Zealand and New Caledonia) that document how one of the largest subduction zones on Earth, the Tonga-Kermadec system, started.
Published: 2023

39. Astrochronology of the Valanginian-Hauterivian stages (Early Cretaceous): chronological relationships between the Paraná-Etendeka large igneous province and the Weissert and the Faraoni events

Author: Pierre Pellenard, Stéphane Reboulet, Mathieu Moiroud, Mathieu Martinez, Laurent Riquier, Jean-François Deconinck, Laboratoire des Fluides Complexes et leurs Réservoirs (LFCR), TOTAL FINA ELF-Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Evolution et Modélisation des Bassins Sédimentaires (EMBS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Departamento de Estratigrafía y Paleontología, Universidad de Granada (UGR), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-07-BLAN-0145,ASTS-CM,Astronomical time scale for the Cenozoïc and Mesozoïc era.(2007), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Universidad de Granada = University of Granada (UGR), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Fluides Complexes et leurs Réservoirs ( LFC-R ), Université de Pau et des Pays de l'Adour ( UPPA ) -Total-Centre National de la Recherche Scientifique ( CNRS ), Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Evolution et Modélisation des Bassins Sédimentaires ( EMBS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Universidad de Granada ( UGR ), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] ( LGL-TPE ), École normale supérieure - Lyon ( ENS Lyon ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), and ANR-07-BLAN-0145,ASTS-CM,Astronomical time scale for the Cenozoïc and Mesozoïc era. ( 2007 )
Subjects: Astrochronology, 010506 paleontology, Global and Planetary Change, astrochronology, Large igneous province, myr, 010502 geochemistry & geophysics, Oceanography, [ SDU.STU.ST ] Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, 01 natural sciences, Cretaceous, Paleontology, Geologic time scale, Hauterivian, 13. Climate action, Stage (stratigraphy), Valanginian, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Faraoni Event, Paraná–Etendeka large igneous province, 14. Life underwater, Geology, Weissert Event, 0105 earth and related environmental sciences
Abstract: 16 pages; International audience; The Geological Time Scale shows large uncertainties on durations and ages of Berriasian to Albian stages (Early Cretaceous), which impact climate and paleoceanographic reconstructions. Here, we provide a new astrochronology of the Hauterivian Stage anchored on (1) recent biostratigraphically well-constrained published radio-isotopic dates, and (2) a previously published astrochronology of the Valanginian Stage. A new duration of the Hauterivian Stage is assessed here at 5.93 ± 0.41 myr. The retained age model, anchored on a latest CA-ID-TIMS U–Pb age from a tuff level in the Hauterivian of the Neuquén Basin (Argentina), dates the base of the Valanginian Stage at − 137.05 ± 1.0 Ma, the base of the Hauterivian Stage at − 131.96 ± 1.0 Ma, and the top of the Hauterivian Stage at − 126.02 ± 1.0 Ma. In addition, the onset of the mid-Valanginian Weissert Event is dated at − 135.22 ± 1.0 Ma and the onset of the Faraoni Event at − 126.73 ± 1.0 Ma. The duration of the mid-Valanginian carbon-isotope excursion, associated to the Weissert Event, is assessed at 5.85 myr, with a rapid phase of increasing δ13C values (0.60 myr), a phase of stable δ13C values (1.48 myr), and smooth decrease in δ13C values (3.77 myr). The calibration provided here highlights that the onset of the activity of the Paraná–Etendeka province and the start of the Weissert Event coincided, suggesting that the Paraná–Etendeka province may have played a major role on the climatic and oceanographic changes during the mid-Valanginian.
Published: 2015

40. Impact of textural anisotropy on syn-kinematic partial melting of natural gneisses: an experimental approach

Author: Ganzhorn , Anne-Céline, Trap , Pierre, Arbaret , Laurent, Champallier , Rémi, Fauconnier , Julien, Labrousse , Loic, Prouteau , Gaëlle, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut des Sciences de la Terre d'Orléans - UMR7327 ( ISTO ), Bureau de Recherches Géologiques et Minières (BRGM) ( BRGM ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire Chrono-environnement (UMR 6249) (LCE)
Subjects: [SDU]Sciences of the Universe [physics], [ SDU ] Sciences of the Universe [physics]
Abstract: International audience; Partial melting of continental crust is a strong weakening process controlling its rheological behavior andductile flow of orogens. This strength weakening due to partial melting is commonly constrained experimentallyon synthetic starting material with derived rheological law. Such analog starting materials are preferentiallyused because of their well-constrained composition to test the impact of melt fraction, melt viscosity and meltdistribution upon rheology. In nature, incipient melting appears in particular locations where mineral and watercontents are favorable, leading to stromatic migmatites with foliation-parallel leucosomes. In addition, leucosomesare commonly located in dilatants structural sites like boudin-necks, in pressure shadows, or in fractures withinmore competent layers of migmatites. The compositional layering is an important parameter controlling melt flowand rheological behavior of migmatite but has not been tackled experimentally for natural starting material. In thiscontribution we performed in-situ deformation experiments on natural rock samples in order to test the effect ofinitial gneissic layering on melt distribution, melt flow and rheological response. In-situ deformation experimentsusing a Paterson apparatus were performed on two partially melted natural gneissic rocks, named NOP1 & PX28.NOP1, sampled in the Western Gneiss Region (Norway), is biotite-muscovite bearing gneiss with a week foliationand no gneissic layering. PX28, sampled from the Sioule Valley series (French Massif Central), is a paragneisswith a very well pronounced layering with quartz-feldspar-rich and biotite-muscovite-rich layers. Experimentswere conducted under pure shear condition at axial strain rate varying from 5*10-6 to 10-3 s-1. The main stresscomponent was maintained perpendicular to the main plane of anisotropy. Confining pressure was 3 kbar andtemperature ranges were 750C and 850-900C for NOP1 and PX28, respectively. For the 750C experimentsNOP1 was previously hydrated at room pressure and temperature. According to melt fraction, deformation ofpartially molten gneiss induced different strain patterns. For low melt fraction, at 750C, deformation within theinitially isotropic gneiss NOP1 is localized along large scales shear-zones oriented at about 60 from main stresscomponent 1. In these zones quartz grains are broken and micas are sheared. Melt is present as thin film (20m) at muscovite-quartz grain boundaries and intrudes quartz aggregates as injections parallel to 1. For highermelt fraction, at 850C, deformation is homogeneously distributed.
Published: 2015

41. Did high Neo-Tethys subduction rates contribute to early Cenozoic warming?

Author: Anne-Véronique Walter-Simonnet, Brahimsamba Bomou, G. Le Hir, Yannick Donnadieu, D.J.J. van Hinsbergen, Nicolas Carry, Bruno Vrielynck, Didier Marquer, Guilhem Hoareau, Laboratoire des Fluides Complexes et leurs Réservoirs (LFCR), TOTAL FINA ELF-Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Sciences [Utrecht], Utrecht University [Utrecht], Modélisation du climat (CLIM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement (UMR 6249) (LCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Fluides Complexes et leurs Réservoirs ( LFC-R ), Université de Pau et des Pays de l'Adour ( UPPA ) -Total-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] ( LSCE ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique du Globe de Paris ( IPGP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -IPG PARIS-Université Paris Diderot - Paris 7 ( UPD7 ) -Université de la Réunion ( UR ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Sciences pour l'environnement ( SPE ), Université Pascal Paoli ( UPP ) -Centre National de la Recherche Scientifique ( CNRS ), Université Bourgogne Franche-Comté ( UBFC ) -Université de Franche-Comté ( UFC ) -Centre National de la Recherche Scientifique ( CNRS ), and Mantle dynamics & theoretical geophysics
Subjects: 010504 meteorology & atmospheric sciences, lcsh:Environmental protection, Stratigraphy, Earth science, [ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.MECA.GEME]Physics [physics]/Mechanics [physics]/Mechanical engineering [physics.class-ph], 010502 geochemistry & geophysics, 01 natural sciences, Carbon cycle, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], [ SDU.STU.GP ] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Paleontology, lcsh:Environmental pollution, Continental margin, Paleoceanography, [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], lcsh:TD169-171.8, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, Global and Planetary Change, Subduction, Palaeontology, Global change, Igneous rock, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [ SPI.MECA.MEMA ] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], [ PHYS.MECA.MEMA ] Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], [ PHYS.MECA.GEME ] Physics [physics]/Mechanics [physics]/Mechanical engineering [physics.class-ph], lcsh:TD172-193.5, [ SPI.MECA.MEFL ] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Climate model, [ SDU.STU.CL ] Sciences of the Universe [physics]/Earth Sciences/Climatology, Cenozoic, Geology
Abstract: The 58–51 Ma interval was characterized by a long-term increase of global temperatures (+4 to +6 °C) up to the Early Eocene Climate Optimum (EECO, 52.9–50.7 Ma), the warmest interval of the Cenozoic. It was recently suggested that sustained high atmospheric pCO2, controlling warm early Cenozoic climate, may have been released during Neo-Tethys closure through the subduction of large amounts of pelagic carbonates and their recycling as CO2 at arc volcanoes. To analyze the impact of Neo-Tethys closure on early Cenozoic warming, we have modeled the volume of subducted sediments and the amount of CO2 emitted along the northern Tethys margin. The impact of calculated CO2 fluxes on global temperature during the early Cenozoic have then been tested using a climate carbon cycle model (GEOCLIM). We show that CO2 production may have reached up to 1.55 × 1018 mol Ma−1 specifically during the EECO, ~ 4 to 37 % higher that the modern global volcanic CO2 output, owing to a dramatic India-Asia plate convergence increase. The subduction of thick Greater Indian continental margin carbonate sediments at ~ 55–50 Ma may also have led to additional CO2 production of 3.35 × 1018 mol Ma−1 during the EECO, making a total of 85 % of the global volcanic CO2 outgassed. However, climate modeling demonstrates that timing of maximum CO2 release only partially fits with the EECO, and that corresponding maximum pCO2 values (750 ppm) and surface warming (+2 °C) do not reach values inferred from geochemical proxies, a result consistent with conclusions arising from modeling based on other published CO2 fluxes. These results demonstrate that CO2 derived from decarbonation of Neo-Tethyan lithosphere may have possibly contributed to, but certainly cannot account alone for early Cenozoic warming. Other commonly cited sources of excess CO2 such as enhanced igneous province volcanism also appear to be up to 1 order of magnitude below fluxes required by the model to fit with proxy data of pCO2 and temperature at that time. An alternate explanation may be that CO2 consumption, a key parameter of the long-term atmospheric pCO2 balance, may have been lower than suggested by modeling. These results call for a better calibration of early Cenozoic weathering rates.
Published: 2015

42. The one year fate of iron oxide coated gold nanoparticles in mice

Author: Jelena Kolosnjaj-Tabi, Benoit Caron, Jeanne Volatron, Lenaic Lartigue, Florence Gazeau, Dan Elgrabli, Iris Marangon, Nathalie Luciani, Damien Alloyeau, Albert Figuerola, Yasir Javed, Teresa Pellegrino, Giammarino Pugliese, Paris-Centre de Recherche Cardiovasculaire (PARCC - UMR-S U970), Hôpital Européen Georges Pompidou [APHP] (HEGP), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Matière et Systèmes Complexes (MSC), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Istituto Italiano di Tecnologia (IIT), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Matière et Systèmes Complexes (MSC (UMR_7057)), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Paris Descartes - Paris 5 (UPD5)-Hôpital Européen Georges Pompidou [APHP] (HEGP), Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Dipartimento di Scienze della Terra [Pisa], University of Pisa - Università di Pisa, Département des sciences de la Terre, Université Paris-Sud - Paris 11 (UP11), Paris-Centre de Recherche Cardiovasculaire ( PARCC - U970 ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Hôpital Européen Georges Pompidou [APHP] ( HEGP ), Matière et Systèmes Complexes ( MSC ), Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Matériaux et Phénomènes Quantiques ( MPQ ), Istituto Italiano di Tecnologia ( IIT ), Institut des Sciences de la Terre de Paris ( iSTeP ), and Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: Aging, Materials science, Polymers, Surface Properties, [SDV]Life Sciences [q-bio], Static Electricity, Iron oxide, General Physics and Astronomy, Nanoparticle, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Nanotechnology, 02 engineering and technology, Alkenes, 010402 general chemistry, Ferric Compounds, 01 natural sciences, Polyethylene Glycols, Mice, chemistry.chemical_compound, Coated Materials, Biocompatible, Animals, General Materials Science, Magnetite Nanoparticles, ComputingMilieux_MISCELLANEOUS, Maleic Anhydrides, Drug Carriers, Nanopartícules, General Engineering, Proteins, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Mice, Inbred C57BL, Nanomedicine, Liver, Nanocrystal, chemistry, Colloidal gold, Nanotoxicology, Injections, Intravenous, Nanoparticles, Surface modification, Gold, 0210 nano-technology, Proteïnes, Spleen, Iron oxide nanoparticles
Abstract: International audience; Safe implementation of nanotechnology and nanomedicine requires an in-depth understanding of the life cycle of nanoparticles in the body. Here, we investigate the long-term fate of gold/iron oxide heterostructures after intravenous injection in mice. We show these heterostructures degrade in vivo and that the magnetic and optical properties change during the degradation process. These particles eventually eliminate from the body. The comparison of two different coating shells for heterostructures, amphiphilic polymer or polyethylene glycol, reveals the long lasting impact of initial surface properties on the nanocrystal degradability and on the kinetics of elimination of magnetic iron and gold from liver and spleen. Modulation of nanoparticles reactivity to the biological environment by the choice of materials and surface functionalization may provide new directions in the design of multifunctional nanomedicines with predictable fate.
Published: 2015

43. Reconsidering Carboniferous–Permian continental paleoenvironments in eastern equatorial Pangea: facies and sequence stratigraphy investigations in the Autun Basin (France)

Author: Mathilde Mercuzot, Sylvie Bourquin, Pierre Pellenard, Laurent Beccaletto, Johann Schnyder, François Baudin, Céline Ducassou, Sylvain Garel, Georges Gand, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Utah, Région Bretagne, and Bureau de Recherches Géologiques et Minières (BRGM)
Subjects: Late-Variscan basin, Gzhelian, Paleogeography, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, General Earth and Planetary Sciences, Continental delta environments, Asselian, Paleoenvironment
Abstract: International audience; The late Carboniferous–early Permian represents a key period in the Phanerozoic history, given the major global geodynamic and climate modifications. The aim of this work is to better understand the context and characteristics of the sedimentation recorded in the continental environments of eastern equatorial Pangea at this time, through the example of the Autun Basin (northeastern Massif Central, France). The Autun Basin contains the historical stratotype of the Autunian continental stage, and its stratigraphy was recently improved by accurate numerical ages. This basin formed in an extensional tectonic context during the latest stages of the Variscan orogeny, and it is essential to study its paleoenvironmental evolution to provide new insights into the sedimentary evolution of contemporaneous surrounding basins. Using field and subsurface data, we propose a refined sedimentological model for the Autun Basin, relying on updated facies interpretations, organic matter content fluctuations, and sequence stratigraphy concepts and correlations. The continental environments of the lower sedimentary succession of the Autun Basin, previously considered to be fluvial and lacustrine, are herein re-interpreted as mainly lacustrine, comprising fine-grained organic matter-rich deposits, and supplied by coarser-grained deltaic siliciclastic sediments, without preservation of strict fluvial sedimentation. The determination of the sequence stratigraphy cycles, strengthened by the quantification of the organic matter content, and reflected by the temporal succession of progradational and retrogradational trends, is used to determine new correlations between several sections, as well as to reconstruct the paleoenvironment evolution at the Carboniferous–Permian transition. This study provides evidence that the sedimentation area of the Autun Basin at the time of its filling was much larger than the preserved basin area, and suggests connections with contemporaneous neighboring French basins, pointing to a large sedimentary system in the northeastern Massif Central area rather than narrow and isolated basins.
Published: 2022

44. Episodic fluid flow in an eclogite-facies shear zone: Insights from Li isotope zoning in garnet

Author: William F. Hoover, Sarah Penniston-Dorland, Lukas Baumgartner, Anne-Sophie Bouvier, Besim Dragovic, Michele Locatelli, Samuel Angiboust, Philippe Agard, Department of Geology, University of Maryland, Institute of Earth Sciences [Lausanne], Université de Lausanne = University of Lausanne (UNIL), Institut des sciences de la terre [Lausanne] (ISTE), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of the Earth, Ocean and Environment, University of South Carolina, Università degli studi di Genova = University of Genoa (UniGe), École normale supérieure de Lyon (ENS de Lyon), Laboratoire de tectonique (LT), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology
Abstract: Episodic fluid overpressure and escape is invoked as a cause or consequence of many subduction-zone seismic phenomena but can be challenging to constrain in exhumed high-pressure metamorphic rocks. In situ measurements of lithium isotopes in garnet reveal evidence of episodic fluid transport in a subduction shear zone now exposed in the Monviso ophiolite (Western Alps). Garnet from an eclogite block and associated metasomatic reaction rind was analyzed by secondary ion mass spectrometry (SIMS). All analyzed garnet preserves core-rim zoning in δ7Li and large negative δ7Li excursions (NEs) in mantles. These excursions cannot be explained by instrumental mass fractionation during analysis, equilibrium fractionation, or intracrystalline diffusion of Li within garnet. Instead, NEs were produced by kinetic fractionation of Li isotopes during bulk diffusion through a pore fluid, and the fractionated isotopic compositions were incorporated into garnet by syn-diffusion growth. Disequilibrium garnet growth textures associated with negative δ7Li support this interpretation and suggest metasomatism drove rapid garnet growth. Four distinct NEs were identified requiring that at least four pulses of fluid were transported within the adjacent shear zone. This evidence of episodic fluid transport along a subduction shear zone at eclogite facies supports models of intermediate-depth seismicity that rely on cyclic fluid overpressure and escape.
Published: 2022

45. A Jurassic record encodes an analogous Dansgaard–Oeschger climate periodicity

Author: Slah Boulila, Bruno Galbrun, Silvia Gardin, Pierre Pellenard, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Paléontologie - Paris (CR2P), Muséum national d'Histoire naturelle (MNHN)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] (BGS), and Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Multidisciplinary, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Science, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Medicine
Abstract: Earth’s past climate exhibits short-term (1500-year) pronounced fluctuations during the last glacial period, called Dansgaard–Oeschger (DO) glacial events, which have never been detected in pre-Quaternary times. The record of DO equivalent climate variability in Mesozoic strata can provide constraints on understanding these events. Here we highlight a prominent 1500-year cyclicity in a Jurassic (~ 155 Ma) ice-free sedimentary record from the Tethyan Basin. This Jurassic 1500-year cyclicity is encoded in high-resolution magnetic susceptibility (MS) proxy data reflecting detrital variations, and expressed as marl-limestone couplets. Additionally, MS data detect the modulation of these DO-scale couplets by supercouplet sets, reflecting the precession and its harmonics. We suggest that this Jurassic DO-like cyclicity may originate from paleo-monsoon-like system, analogous to the record of DO events in the Pleistocene East Asian monsoon archives. Paleogeographic reconstructions and atmosphere–ocean simulations further support the potential existence of strong, ancient monsoon circulations in the Tethyan Basin during the Jurassic.
Published: 2022

46. The Paleogene continental basins from SE France: new geographic and climatic insights from an integrated approach

Author: Nazim Semmani, François Fournier, Jean-Pierre Suc, Séverine Fauquette, Nicolas Godeau, Abel Guihou, Speranța-Maria Popescu, Mihaela Carmen Melinte-Dobrinescu, Christophe Thomazo, Lionel Marié, Pierre Deschamps, Jean Borgomano, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], GeoBioStratData.Consulting, National Institute of Marine Geology and Geoecology (Romania), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Géologie des systèmes carbonatés (EA 4234), Université de Provence - Aix-Marseille 1, Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and APIC 2018 RRH and Carbonate Chair (CEREGE)
Subjects: Rupelian, climatostratigraphy, Priabonian, [SDU]Sciences of the Universe [physics], U/Pb dating, Paleontology, pollens, marine intrusion, Oceanography, strontium and sulfur isotopes, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes, Eocene-Oligocene Transition
Abstract: International audience; New insights into the geodynamic evolution, the paleogeographic framework and the paleoclimatic setting of the Upper Eocene-Oligocene lacustrine basins from SouthEast France have been provided by an integrative approach combining geochronology, micropaleontology and stable isotope analyses. U-Pb dating on calcite, pollen-based climatostratigraphy and strontium and sulfur isotope signatures of sulfates provided a robust chronostratigraphic framework for the Upper Eocene and Oligocene succession from the Vistrenque, Alès and Roussillon basins. The thick Priabonian-lower Rupelian lacustrine succession from the Vistrenque Basin is interpreted to be deposited in a strike-slip basin associated with the latest stages of pyrenean shortening. Floral assemblages are used to reconstruct the vegetation cover in the lacustrine systems and their neighbouring lowlands and highlands. Composition of saltwater inferred from strontium and sulfur isotope signatures of sulfates, the occurrence of calcareous nannofossils, dinoflagellate cysts and pollen grains of mangrove-related plants provided strong evidence for marine intrusions into the Alès Basin during the Priabonian and the Vistrenque Basin during the Rupelian and Chattian. Paleogeographic reconstructions of Southeast France during the Priabonian and late Rupelian strongly suggest marine incursions from the Alpine Sea via two potential pathways: upper Rhône Valley via the Crest Sill and lower Rhône Valley via the Haut-Var Pyrenean synclines. On the other hand, Upper Oligocene evaporite basins in the Camargue area have been subjected to marine intrusions from the Western Mediterranean Sea following the collapse of the eastern pyrenean relief during the Liguro-Provençal rifting stage. Finally, pollen analysis and Climate Amplitude Method revealed a brief but significant stage of cooling and aridification at the very base of the Rupelian which could represent the regional and terrestrial expression of the global climate cooling following the Eocene-Oligocene Transition.
Published: 2023

47. A 20‐million‐year Early Jurassic cyclostratigraphic record and its implications for the chaotic inner Solar System and sea‐level changes

Author: Guillaume Charbonnier, Slah Boulila, Bruno Galbrun, Jacques Laskar, Silvia Gardin, Isabelle Rouget, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Paléontologie - Paris (CR2P), and Muséum national d'Histoire naturelle (MNHN)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: sea-level change, Early Jurassic, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Geology, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
Abstract: International audience; We present high-resolution (every 2 cm) magnetic susceptibility (MS) data from the Sancerre-Couy drill core (Paris Basin), spanning the latest Sinemurian to the earliest Aalenian (Early Jurassic). This record allows to build a 20-million-year cyclostratigraphic interval using the stable 405 kyr (g2–g5) orbital eccentricity cycle and to focus on long-period cyclicities and their potential implications for the chaotic diffusion in the inner Solar System and sea-level changes. Time series analysis indicates evidence of two long-period cyclicities of 1.6 and 3.4 Myr. These Early Jurassic cyclicities likely correspond to the Cenozoic orbital cyclicities of 2.4 Myr (g4–g3) and 4.7 Myr eccentricity terms. Shortening of eccentricity terms during the Early Jurassic is potentially related to the chaotic orbital motion of the inner planets expressed in the resonant argument θ = 2(g4–g3) − (s4–s3). The 1.6 Myr (g4–g3) cycle matches the third-order eustatic sequences, whereas the 3.4 Myr cycle has no equivalent in the reference eustatic chart. These cycles of several million years are superimposed a cyclicity of ca. 7.5 Myr, which may correspond to the eccentricity term of 9.5 Myr, previously detected in the Cenozoic. Such cyclicity matches the global, ‘shorter’ second-order sea-level sequences and is strongly documented in the sedimentological and mineralogical proxy data, hence supporting the potential key role of orbitally paced climate and sea-level changes at this timescale.
Published: 2023

48. Current motion and deformation of the Nazca Plate: new constraints from GPS measurements

Author: P Jarrin, J-M Nocquet, F Rolandone, H Mora-Páez, P Mothes, D Cisneros, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Colombian Geological Survey (CGS), Instituto Geofísico, Instituto Geográfico Militar de Ecuador, and ANR-19-CE31-0003,S_5,Séismes Lents & Essaims Sismiques(2019)
Subjects: Plate motions, Geophysics, Pacific Ocean, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Satellite geodesy, Plate motions Satellite geodesy Pacific Ocean South America, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, South America, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience; We use new GPS data to determine an updated Euler pole describing the present-day motion of the oceanic Nazca Plate. Our solution includes continuous GPS (cGPS) measurements at Malpelo Island offshore Colombia, two sites in the Galapagos archipelago, Easter Island and Salas y Gomez Island in the western part of the plate and Robinson Crusoe Island offshore Chile. A careful analysis of geodetic time-series reveals that (1) previous estimates using former cGPS site EISL are biased by several millimetres per year eastward due to station malfunctioning (2) north velocity component of cGPS site GLPS at Santa Cruz Island in the Galapagos is impacted by volcanic deformation at the 1-2 mm yr-1 level, probably caused by the recurrent volcanic activity of the Sierra Negra volcano. In addition, we find shortening at ~1 mm yr-1 between Easter Island (cGPS ISPA) and Salas y Gomez Island (cGPS ILSG), consistent with the elastic deformation induced by rapid opening at the East Pacific rise. cGPS site at Robinson Crusoe Island shows ~4-5 mm yr-1 abnormally fast East velocity induced by the visco-elastic relaxation following the Maule Mw 8.8 2010 earthquake. Using this information, we determine a new Euler pole (longitude: -90.93°E, latitude 56.19°N, 0.588 deg Myr-1) describing the present-day Nazca-South America Plate motion, using five sites (Malpelo Island, two sites in the Galapagos archipelago, Easter Island and Salas y Gomez Island). The proposed Euler pole provides a weighted root mean square (wrms) of residual velocities of 0.6 mm yr-1, slightly higher than usually observed for other major tectonic plates and accounting for the uncertainty of potential volcanic-tectonic deformation. Our model predicts a maximum convergence rate at 65.5 ± 0.8 mm yr-1 at latitude ~30°S along the Chile trench, decreasing to 50.8 ± 0.7 mm yr-1 in northern Colombia and 64.5 ± 0.9 mm yr-1 in southern Chile (1σ confidence level). Comparison with the geological models NUVEL1A and MORVEL indicates constant decrease since 3.16 Ma of opening rate along the Nazca-Antarctic Plate boundary spreading centres at ~1 cm yr-1 per Myr. Combined with the ITRF2014 pole for the Pacific and Antarctic plates, our derived Euler pole predicts closure at the ~1 mm yr-1 level for Pacific-Antarctic-Nazca Plate circuit. However, combining our results with MORVEL estimates for the Cocos Plate, the non-closure of the Pacific-Cocos-Nazca Plate circuit is 9.7 ± 1.6 mm yr-1, 30 per cent lower than the 14 ± 5 mm yr-1 reported in MORVEL model, but still significant. A small (~1.5 mm yr-1) velocity residual at Malpelo Island neither supports the hypothesis of an independent Malpelo microplate offshore Colombia nor large scale internal deformation induced by thermal contraction. Our solution rather suggests that non-closure of the Pacific-Cocos-Nazca Plate circuit arises from the determination of the Cocos Plate motion in MORVEL, an hypothesis further supported by the large discrepancy between MORVEL's prediction and the observed GPS velocity observed at Cocos Islands (cGPS ISCO).
Published: 2023

49. Gravity-driven large-scale deformation system in the Tumbes-Guayaquil forearc basin, Northern Andes (Northern Peru-Southern Ecuador)

Author: Peuzin, Andréa, Saillard, Marianne, Espurt, Nicolas, Michaud, François, Bulois, Cédric, Praeg, Daniel, Régnier, Marc, Calderon, Ysabel, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Sorbonne Université (SU), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PERUPETRO, and ANR-18-CE31-0022,MARACAS,Les terrasses marines comme proxy pour l'appréhension de l'aléa sismique(2018)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Gravity tectonics High sedimentation Overpressured shales Crustal deformation North Peru-South Ecuador forearc
Abstract: International audience; The offshore Tumbes-Guayaquil forearc basin in the accretionary prism of Northern Peru-Southern Ecuador shows evidence of gravity-driven large-scale deformation systems active during the Late Neogene-Quaternary period. Subsurface data and the construction of eight structural cross-sections show that the ~8 km-thick Oligocene-Quaternary sedimentary infill is detached seaward and completely decoupled from the underlying inner accretionary prism systems. The Corvina décollement in the Tumbes basin and the Posorja décollement in the Guayaquil basin constitute two thinskinned gravity tectonic systems associated with kilometer-scale, updip "raft" extensional structures paired with downdip fold-thrust systems (Barracuda and Domito thrust systems). Although many previous studies have described the structural and stratigraphic architecture of the Tumbes-Guayaquil forearc basin, no model explicitly accounts for this anomalous large-scale gravity tectonics. We propose that this gravity tectonic style, more commonly observed in passive continental margins, is primarily controlled by the combination of tectonostratigraphic features, including crustal-scale transtensional deformation related to oblique convergence along the Northern Andean margin, basal décollement slope tilting, strong sediment accumulation, and the presence of overpressured shales.
Published: 2023

50. Evaluation of Tsunami Inundation in the Plain of Martil (North Morocco): Comparison of Four Inundation Estimation Methods

Author: Basquin, Elise, El Baz, Apolline, Sainte-Marie, Jacques, Rabaute, Alain, Thomas, Maud, Lafuerza, Sara, El M'Rini, Abdelmounim, Mercier, Denis, D’acremont, Elia, Bristeau, Marie-Odile, Creach, Axel, Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Numerical Analysis, Geophysics and Ecology (ANGE), Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jacques-Louis Lions (LJLL (UMR_7598)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Probabilités, Statistique et Modélisation (LPSM (UMR_8001)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Abdelmalek Essaadi University [Tétouan] (UAE), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (Nantes Univ - IGARUN), Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), and Institut de l'Océan de Sorbonne Université
Subjects: Risk Management, Inundation maps, [SDE]Environmental Sciences, Coastal hazard, Alboran sea, Exposure
Abstract: International audience; The Alboran Basin may be subject to tsunami hazards. If such an event were to occur, it is expected that the urbanised and densely populated areas of northern Moroccan coastline would be affected. Precise inundation hazard maps are needed for tsunami risk management in this region. In this article, we argue that the diversity of hazard mapping methods ensures the robustness of the scientific knowledge about the exposure of a territory. Hence, the main objective of this study is to analyse the exposure of the plain of Martil (north of Morocco), by using four hazard mapping methods to create inundation maps for two scenarios of tsunamis generated by extreme submarine mass failure (SMF) in the Alboran Sea, of 0.9 km3 and 3.8 km3 respectively. A digital terrain model of the plain was used to explore four methods of inundation mapping. The static method identified 4.32 km2 and 19.83 km2 of flooded areas for each scenario using water height values as inundation thresholds. The hybrid and the volumetric methods use the volume of water to determine the inundation extent. For the first scenario, 3.51 km2 of the plain were inundated using the hybrid method, and 20.11 km2 for the second scenario. The results of the volumetric methods are 2.32 km2 and 7.82 km2 respectively for the first and second scenario. Finally, the fourth method relies on numerical hydrodynamic modelling of tsunami inundation (Freshkiss3d® code). With this method, 4.55 km2 of the plain were flooded in the first scenario, and 24.12 km2 for the second. The comparison of the results highlights that the most sensitive areas to tsunami inundation are the lowest topographic ones, being the beaches and the wadis floodplains. This result raises questions on the current coastal development and the preparedness of its population, thus calling for more attention to engage on tsunami risk management related questions.
Published: 2023

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