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1. 36Cl, a new tool to assess soil carbon dynamics

Author

Cécile Grapeloup, Sophie Cornu, Xavier Giraud, Julie Pupier, Aster Team, Valery Guillou, Philippe Ciffroy, Beatriz Lourino Cabana, Cécile Couegnas, Christine Hatté, and Lucilla Benedetti

Subjects
Medicine, Science
Abstract

Abstract Soil organic carbon is one of the largest surface pools of carbon that humans can manage in order to partially mitigate annual anthropogenic CO2 emissions. A significant element to assess soil sequestration potential is the carbon age, which is evaluated by modelling or experimentally using carbon isotopes. Results, however, are not consistent. The 14C derived approach seems to overestimate by a factor of 6–10 the average carbon age in soils estimated by modeling and 13C approaches and thus the sequestration potential. A fully independent method is needed. The cosmogenic chlorine nuclide, 36Cl, is a potential alternative. 36Cl is a naturally occurring cosmogenic radionuclide with a production that increased by three orders of magnitude during nuclear bomb tests. Part of this production is retained by soil organic matter in organochloride form and hence acts as a tracer of the fate of soil organic carbon. We here quantify the fraction and the duration of 36Cl retained in the soil and we show that retention time increases with depth from 20 to 322 years, in agreement with both modelling and 13C-derived estimates. This work demonstrates that 36Cl retention duration can be a proxy for the age of soil organic carbon.

Published
2023
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2. Modelling the atmospheric chlorine 36 dry deposition on grass using micrometeorology

Author

Deo-Gratias Sourabie, Didier Hebert, Lucilla Benedetti, Elsa Vitorge, Beatriz Lourino-Cabana, Valery Guillou, and Denis Maro

Abstract

Chlorine 36 (36Cl, T1/2 = 301,000 years) is a radionuclide with natural and anthropogenic origin that can be rejected during decommissioning of nuclear power plants or chronically during recycling of used nuclear fuels. Once emitted into the atmosphere, chlorine 36 (gas and particles) can be transferred to the soil and vegetation cover by dry and wet deposition. However, quantitative constraints of these deposits are very scarce. Because of its relatively high mobility in the geosphere and its high bioavailability, chlorine 36 fate in the environment should be studied for environmental and human impact assessments.The aim of this study is therefore to develop dry depositional models for the gaseous and particulate fractions of chlorine 36. The model used for the parameterization of gaseous chlorine 36 dry deposition on grass is the << Big-leaf >> model based on the electrical analogy (Seinfield 1985). It was adapted from the Bah (2020) model developed for iodine. For particulate chlorine 36, the Damay-Pellerin (2017) model was used. This model requiring the diameter of particulate chlorine 36 to be known, a sample of aerosol was taken in the chlorine 36 plume to determine on which particle size it is fixed. The sampling was performed on a low pressure impinger (LPI, DEKATI) of 13 levels for particles with diameters between 30nm and 10μm. In order to obtain model input data, meteorological and micrometeorological parameters were measured continuously at the IRSN La-Hague technical platform (PTILH, France). The PTILH is located 2 km north of Orano La-Hague plant which emits small quantities of chlorine 36. An ultrasonic anemometer (Young 81000V) installed at a height of 4,5 m from the ground measured the direction (°), the velocity u (m/s) and the air friction velocity u* (m/s), the sensible heat flux H, the Monin-Obukhov length (L) and the atmospheric stability (1/L). A weather station (Spectrum Watchdog, series 2000) measured temperature Ts (°C), relative humidity RH (%), dew point (°C), global radiation SR (Wat/m2) and photosynthetic active radiation PAR (μM/m2.s). Sampling campaigns of 2 weeks were also conducted at the PTILH site to determine experimental depositional rates of chlorine 36. Chlorine 36 measurements were carried out by acceleration mass spectrometry at CEREGE-LN2C (France).The particle size distribution of the aerosol sample from chlorine 36 plume shows two peaks, a main one at 2μm and a second one at 10μm, typical distribution of marine aerosol. The models yield chlorine 36 depositional velocities between 6,7.10-3 and 10-2 m/s for the particulate fraction, and between 5.10-3 and 1,3.10-2 m/s for the gaseous one. The total dry depositional velocities (particles and gas) calculated from the model are less than one order of magnitude than the ones obtained experimentally.

Published
2023
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3. Cenozoic uplift history and topographic rejuvenation of the northern Atlas-Meseta system (Morocco)

Author

Romano Clementucci, Paolo Ballato, Lionel Siame, Faccenna Claudio, Racano Simone, Torreti Giacomo, Lanari Riccardo, Leanni Laetitia, and Valery Guillou

Abstract

Transient topography represents an opportunity for extracting information on the combined effect of tectonics, mantle-driven processes, lithology and climate across different temporal and spatial scales. The geomorphic signature of transient conditions can be used to unravel the landscape evolution and to assess perturbations in uplift rates, especially in areas devoid of stratigraphic constraints. The Atlas-Meseta system experienced a large scale topographic rejuvenation during the Cenozoic through a combination of different processes. Despite the uplift, the Western Moroccan Meseta (WMM) represents a quiescent tectonic domain with deeply incised valleys and high-standing erosional surfaces (relict landscape). This topography is characterized by elevated non-lithological knickpoints, that delimit an uplifted relict landscape, implying a transient response to a change in uplift rates. Here, we determine denudation rates of selected watersheds and bedrock outcrops from cosmogenic nuclides and perform stream profile, regional and basin-scale geomorphic analysis. Denudation rates of the relict and the rejuvenated landscape range from 15 to 20 m/Myr and from 30 to 40 m/Myr, respectively. These results allow estimating the erodibility parameter for performing river-profile inversions and hence extracting rock uplift rates through time. Inverted rock uplift rates are 10-25 m/Myr from 45 to 22 Ma and 30-55 m/Myr from 22 to 10 Ma. Despite the different time scales, the inverted rates are consistent with 10Be averaged denudation rates (15-20 and 30-40 m/Myr) and river incision values from Pleistocene lava flows (

Published
2023
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4. Lithological control on erosional dynamics in a tectonically inactive mountain belt (Anti-Atlas, Morocco)

Author

Romano Clementucci, Paolo Ballato, Lionel Siame, Claudio Faccenna, Ahmed Yaaqoub, Abderrahim Essaifi, Laëtitia Leanni, Valery Guillou, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), and 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)

Subjects
[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU]Sciences of the Universe [physics], [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, ComputingMilieux_MISCELLANEOUS
Abstract

Topographic relief results from the complex interactions between tectonics and erosional surface processes. The efficiency of surface processes is a function of topographic slopes, bedrock erodibility and climatic conditions. Ancient orogens offers a favourable setting to isolate the contribution of lithology, as tectonically driven surface uplift is typically negligible and channel steepness is directly controlled by bedrock erodibility. The Anti-Atlas in NW Africa is a late Paleozoic orogen that contains a well-preserved, uplifted, relict landscape that has been slowly eroding since the late Cretaceous. Here, we combine geomorphic analysis with 10Be-derived denudation rates, to quantify the impact of bedrock erodibility and get insight into the surface evolution of the Anti-Atlas and the adjacent Siroua Massif. Specifically, we show that basin-wide denudation rates from the relict landscape range from 5 to 20 m/Myr, in agreement with the average long-term rates estimated from eroded volumes of Miocene volcanics and available thermochronometric data. This suggests that the regional relict topography has attained an erosional steady state and has been slowly decaying over geological time. Our results are comparable with data from other tectonically quiescent settings and demonstrate a positive linear correlation between denudation rates and normalized channel steepness indices. This allows constraining a narrow range of bedrock erodibility values for different rock-types (quartzite, granitic and sedimentary rocks), that are comparable with estimates from different stable settings. Finally, our compilation from tectonically inactive regions indicates that channel steepness, denudation rates and bedrock erodibility do not change significantly across different climatic zones and precipitation regimes highlighting the critical role of lithology in controlling the topographic relief.

Published
2023
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6. Age and recurrence of coseismic rock avalanches in sierra de la sobia (Cantabrian mountains, Spain)

Author

Laura Rodríguez-Rodríguez, Francisco José Fernández, Rosana Menéndez-Duarte, Valery Guillou, Beatriz Puente-Berdasco, Vincent Rinterknecht, and ASTER Team

Subjects
Earth-Surface Processes
Abstract

This research has been funded by the Spanish Ministry of Science and Innovation (Projects: CGL2015-66997-R and PID2021-126357NB-100), and by the European Regional Development Fund (FEDER) and Plan de Ciencia Tecnología e Innovación del Principado de Asturias (PCTI) (Grant reference: FC-GRUPIN-IBI/2018/00076/040). The ASTER AMS national facility (CEREGE, Aix-en-Provence) is supported by the INSU/CNRS, the ANR through the “Projets thématiques d’excellence” program for the “Equipements d’excellence” ASTER- CEREGE action and IRD.

Published
2023

7. Temporal recurrence of hazardous rock avalanches in Sierra de La Sobia (Cantabrian Mountains, Spain)

Author

Laura Rodríguez-Rodríguez, Francisco José Fernández-Rodríguez, Rosana Menéndez-Duarte, Valery Guillou, Beatriz Puente-Berdasco, Vincent Rinterknecht, Georges Aumaître, Karim Keddadouche, and Didier Bourlès

Abstract

Rock avalanches are voluminous debris instabilities originated from a fallen portion of bedrock that suffers pervasive disintegration [1]. Tough rock avalanches are foreseen as low-frequency events, their volume (>106 m3) and runout distance (kilometric scale) make them extremely hazardous processes in populated mountain settings and key contributors to landscape denudation [2]. Deciphering the timing of recurrent rock avalanches is crucial to understand the triggering factors involved in their origin (e.g., role of seismicity) and for risk assessment.This study focuses on a rock avalanche cluster preserved in the southern flank of Sierra de la Sobia; a limestone massif located in the Cantabrian Mountains (North Spain). The rock avalanche cluster analyzed is spatially related to the Marabio Fault trace, which shows unequivocal evidence of Quaternary activity [3]. Rock avalanches in this area have been interpreted as coseismic based on the following evidence [4]: (i) boulder populations show fractal block-size distributions consistently with dynamic fragmentation; (ii) the kinematic analysis of local minor transverse and parallel faults points to a horizontal N-S compression consistent with the regional stress field; and (iii) slope stability analysis indicates that headscarps will turn unstable if ground acceleration peak rises to 0.10–0.15 g during an earthquake, which is within the values expected according to the 2013 European Seismic Hazard Map. A first attempt of numerical dating was performed through the U-Th technique on calcite cements found in the oldest rock avalanches. Results suggest multiple episodes of cementation during the last ~280 ka, but age dispersion hinders the age bracketing of instability events4. Here we present a collection of twenty cosmic ray exposure ages relying on the isotope Cl-36 obtained from limestone boulders sampled in the youngest accumulation bodies of the Entrago and Carrea rock avalanches. Results allow to constrain up to 5 instability events spanning the last ~22 ka and occurring at average recurrence intervals of ~3.6 ka. The youngest rock avalanche event took place 8.5 ka ago and left boulder accumulations close to the headscarp of both rock avalanches. Boulder age dispersion increases accordingly with the increase in runout distance from the headscarp, possibly due to the spatial overlapping of accumulation bodies resulting from different instability events of seismic origin. These preliminary results are promising, because if extended to other rock avalanche clusters of the Cantabrian Mountains, they could help to decipher the recurrence time of severe earthquakes in mountain settings where tectonic deformation occurs at low to moderate rates.[1] Hermanns, R. L. Encyclopedia of Natural Hazards. vol. 2 (2013).[2] Davies, T. Rock Avalanches. In Oxford Research Encyclopedia of Natural Hazard Science 58 (Oxford University Press, 2018). doi:10.1093/acrefore/9780199389407.013.326.[3] Fernández, F. J., Alonso, J. L. & Pando, L. Evidence for quaternary tectonic activity in the western cantabrian Zone (Passes of Marabio, Sobia nappe). Geogaceta 64, 1–3 (2018).[4] Fernández, F. J., Menéndez-Duarte, R., Pando, L., Rodríguez-Rodríguez, L. & Iglesias, M. Gravitational slope processes triggered by past earthquakes on the Western Cantabrian Mountains (Sierra de la Sobia, Northern Spain ). Geomorphology 390, 107867 (2021).

Published
2022
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8. Asynchronous dynamics of the last Scandinavian Ice Sheet along the Pomeranian Phase ice-marginal belt: a new scenario inferred from surface exposure 10Be dating

Author

Karol Tylmann, Piotr P. Woźniak, Vincent Rinterknecht, Valery Guillou, and ASTER Team

Abstract

We present a new set of 25 10Be surface exposure ages of boulders located on the Pomeranian moraines and of erratic boulders located directly upstream of the Pomeranian moraines in northern Poland. Together with recalculated 10Be surface exposure ages along the Pomeranian Phase ice-marginal belt from Denmark to the west to Lithuania and Belarus to the east, the full data set (n = 86) enabled us to constrain the timing of the ice front standstill and its subsequent retreat. The investigated area consists of geomorphological record along ~2000 km of the ice margin associated with the ice sheet limit correlated so far with the Late Weichselian Pomeranian Phase (Bælthav in Denmark, Baltija in Lithuania and Braslav in Belarus).We constrained the age of the ice margin position in the area occupied by the Baltic Ice Stream to ~20–19 ka, in the area occupied by the Odra Ice Stream to ~19–18 ka, in the interstream area between the Odra and the Vistula Ice Streams to ~20–19 ka, in the area occupied by the Vistula Ice Stream to ~19–18 ka, in the area occupied by the Mazury Ice Stream to ~18–17 ka, in the area occupied by the Riga Ice Stream to ~17–16 ka, and in the area occupied by the Novgorod Ice Stream to ~16–15 ka. Our best age estimates are based on: (1) a minimum age of the ice margin retreat inferred from new and recalculated 10Be ages of boulders as well as interpretation of available radiocarbon ages from organic deposits and OSL ages from sediments overlying tills, and (2) a maximum age of the ice margin stillstand and retreat inferred from interpretation of available OSL ages from sandur sediments deposited in front of the ice sheet. The asynchrony of the ice margin positions along the Pomeranian Phase ice-marginal belt shows about 3–5 ka difference between the Bælthav ice margin in Denmark and the Braslav ice margin in Belarus. We propose a new scenario of the Pomeranian Phase ice sheet evolution and a time-slice reconstruction of the last Scandinavian Ice Sheet’s southern fringe for the period ~20–15 ka.

Published
2022
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10. Lithological control on topographic relief evolution in a slow tectonic setting (Anti-Atlas, Morocco)

Author

Romano Clementucci, Paolo Ballato, Lionel L. Siame, Claudio Faccenna, Ahmed Yaaqoub, Abderrahim Essaifi, Laëtitia Leanni, Valery Guillou, 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), Università degli Studi Roma Tre = Roma Tre University (ROMA TRE), Université Cadi Ayyad [Marrakech] (UCA), Clementucci, R., Ballato, P., Siame, L. L., Faccenna, C., Yaaqoub, A., Essaifi, A., Leanni, L., and Guillou, V.

Subjects
denudation rates, Geophysics, Atlas Mountains, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Geochemistry and Petrology, bedrock erodibility, Earth and Planetary Sciences (miscellaneous), cosmogenic nuclides, quantitative geomorphology, bedrock erodibility, denudation rates, Atlas Mountains, topographic relief, cosmogenic nuclides, quantitative geomorphology, topographic relief
Abstract

International audience; Topographic relief results from the complex interactions between tectonics and erosional surface processes, which are primarily mediated by bedrock erodibility and climatic conditions. Ancient orogens offer a favourable setting to isolate the contribution of lithology, as tectonically driven rock uplift is typically negligible and rock strength variability can exert a critical role on the evolution of the topography. The Anti-Atlas in NW Africa is a late Paleozoic orogen comprising a well-preserved, elevated, relict landscape delimited by non-lithological knickpoints, that was uplifted during a regional late Cenozoic phase of topographic rejuvenation. Here, we combine a geomorphic analysis with 10Be-derived denudation rates to quantify bedrock erodibility and get insight into the surface evolution of the Anti-Atlas and the adjacent Siroua Massif. Specifically, we show that 10Be basin-wide denudation rates for the relict landscape are rather uniform and range from 5 to 12 m/Myr. These rates agree with long-term rates estimated from different methods suggesting that the relict topography archives erosional quasi-erosional steady-state conditions at least since the latest Cretaceous. The uniformly low 10Be denudation rates in the relict topography are consistent despite the variability in channel steepness and topographic relief that correlates with changes in rock type. The expansion of this analysis to the denudation rates of the downstream portion of the landscape, allows to demonstrate a linear relationship between denudation and channel steepness for catchments draining quartz bearing lithologies. This provides the chance to constrain a narrow range of bedrock erodibility values for different rock-types (quartzite, granitic and sedimentary rocks). These values are comparable with estimates from other slowly deforming settings. Specifically, our compilation from tectonically inactive to slow tectonic regions indicates that bedrock erodibility does not change significantly across different climatic zones and precipitation regimes. This highlights the critical role of lithology in controlling the production of topographic relief in post-orogenic/slow tectonic settings. Finally, we calculate the predicted denudation rates for the steeper portions of the landscape that adjusted to the new uplift rates based on the linear correlation between erosion rates and normalized steepness indices. These rates range from 20 to 50 m/Myr and agree with the direct measurements from two catchments.

Published
2022
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11. Interplay of fluvial incision and rockfalls in shaping periglacial mountain gorges

Author

Swann Zerathe, Thibaut Cardinal, Stéphane Schwartz, Thierry Dumont, Aster Team, Carole Petit, Jérôme Nomade, Laurence Audin, Valery Guillou, Yann Rolland, Régis Braucher, Laurent Borgniet, Institut de Recherche pour le Développement (IRD), 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 Grenoble Alpes (UGA)-Université Gustave Eiffel-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Laboratoire des EcoSystèmes et des Sociétés en Montagne (UR LESSEM), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), 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), French Geological Survey BRGM(Bureau de Recherches Geologiques etMinieres) through the national program 'Referentiel Geologique de France' (RGF-Alpes), AO7 OSUG@2020 : ANR10 LABX56, CNRS-INSU SYSTER Program, Centre National de la Recherche Scientifique (CNRS), French National Research Agency (ANR), IRD, 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 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), Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Grenoble Alpes (UGA), French Geological Survey BRGM (Bureau de Recherches Géologiques et Minières) through the national program 'Référentiel Géologique de France'(RGF-Alpes), ANR-10-LABX-0056,OSUG@2020,Innovative strategies for observing and modelling natural systems(2010), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), and Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])

Subjects
High-resolution 3D mapping, 010504 meteorology & atmospheric sciences, Drainage basin, CRE Cl-36 dating, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, Fluvial incision, 01 natural sciences, Rockfall, Paraglacial, CRE 36Cl dating, Glacial period, Geomorphology, 0105 earth and related environmental sciences, Earth-Surface Processes, geography, geography.geographical_feature_category, Southwestern Alps, Rockfalls, 15. Life on land, Tectonics, [SDE]Environmental Sciences, Erosion, Mountain gorge, Quaternary, Mountain range, Geology
Abstract

International audience; Fluvial incision is the consequence of landscape readjustment to combined tectonic and climatic processes. In the southwestern Alps (Haute Provence Geopark), deep gorges incised by the Bes River attest of efficient erosional processes at the front of the Alpine mountain range. This catchment stands in a peripheral Alpine position, out of the glaciated domain during the last glacial periods, which makes it suitable to quantify fluvial incision and related erosional processes in a glacier-free environment. In this paper, we combine high resolution 3D topographic mapping and in situ produced cosmogenic Cl-36 dating of a mountain gorge (the "Clue de Barles" Gorge). First, the very high-resolution 3D topographic modeling from aerial and drone surveys permits to map the erosion markers on the gorge walls and to accurately determine the topographic shielding factor for Cosmic Ray Exposure (CRE) dating. Secondly, Cl-36 CRE age distribution highlights two distinct geomorphic domains along the vertical profile: i) the higher section is characterized by clusters of similar CRE ages, interpreted as related to paraglacial rockfall events; ii) the lower section shows increasing ages with height, which are ascribed to fluvial incision occurring at a rate of 0.15 mm/yr since 25 ka, and of 2 mm/yr since 2 ka. Our results for the Clue de Barles, compared to other sites in the South French Alps highlight that: i) the gorge morphology is the result of the combination of both vertical fluvial incision and lateral gravitational processes, ii) the mean Quaternary fluvial incision rate in the Bes River catchment is at least twice lower than further east in the formerly glaciated Alps. (C) 2021 Elsevier B.V. All rights reserved.

Published
2021
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12. 36Cl exposure dating of post-glacial features along the Mt Vettore Fault (Central Apennines, Italy) constraining fault slip rate and last glacial advance

Author

Magali Rizza, Bruno Pace, Lucilla Benedetti, Irene Puliti, Jules Fleury, Léa Pousse-Beltran, Aster Team, Paolo Boncio, Valery Guillou, 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), and Università degli studi 'G. d'Annunzio' Chieti-Pescara [Chieti-Pescara] (Ud'A)

Subjects
geography, geography.geographical_feature_category, 13. Climate action, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Glacial period, Fault (geology), Fault slip, Geology, Seismology
Abstract

In the Central Apennines (Italy), up to now, no absolute dating directly based on the moraines has been carried out to constrain glacial oscillation. However, climatic constrains are often used in the Central Apennine to estimate long term (> 10 ka) fault slip rate. In addition slip rate assessments based on offset morphotectonic markers on the main branches of fault systems and encompassing several seismic cycles (> 10 ka) are sparse. This is particularly true for the Monte Vettore-Monte Bove fault system which triggered the 2016-2017 seismic sequence. We thus provide new assessment for the vertical slip rates along the Mt Vettore-Mt Bove fault system. Offset measurements were made using a 5-cm resolution DEM obtained through a drone survey and constrain a fault scarp height of 15.5 ± 1.4 m and a cumulative offset of 32-40.5 m. Samples were collected from the Valle Lunga terminal moraine at 1710 m asl and yield 36Cl exposure ages of 12.7 + 2.2/-1.9 ka while the flat, abraded surface located on top of the tectonic scarp yield 36Cl exposure ages of 23.4 + 5.3/-4.3 ka. Assuming the offset started to accumulate when climate conditions allow its preservation, thus once the surface was abandoned, we constrain a vertical slip rate of 1.2 ± 0.2 mm/yr along the master branch of the Mt Vettore normal fault. This rate is higher than the ones previously obtained from trenches along secondary splays of the Mt Vettore-Mt Bove and on the Norcia fault systems. Besides, the yielded chronology for the last glacial maximum in that area at ~23 ka is in good agreement with the timing previously proposed for the LGM in the Apennines.

Published
2021
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13. Does lithology control post-orogenic topography and rock erodibility? Insight from Anti-Atlas of Morocco

Author

Abderrahim Essaifi, Claudio Faccenna, Romano Clementucci, Lionel Siame, Paolo Ballato, Laëtitia Léanni, Valery Guillou, Ahmed Yaaqoub, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), and 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)

Subjects
Lithology, Atlas (topology), [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Geomorphology, Geology, ComputingMilieux_MISCELLANEOUS
Abstract

Rock erodibility plays a central role in setting topographic limits on relief development and is a key parameter in landscape evolution models. However, channel bed erodibility (K) is usually either fixed arbitrary or let varying over a wide range of values (10-12 – 10-3) because it is difficult to estimate. The topography of ancient orogens offers favourable conditions to quantify bedrock erodibility through the stream profile analysis, because the channel steepness is directly related to rock erodibility rather than rock uplift or climate variability.The Anti-Atlas is a Variscan (Paleozoic) orogen of NW Africa that has not been drifted for long distances over the late Cenozoic and hence has not experienced an extended shift across climatic zones. Furthermore, it is characterized by a well preserved uplifted relict landscape with rather uniform erosion rates since at least the last 120 - 100 Ma. This specific configuration allows studying in detail landscape erosional dynamics and erodibility.Here, we combine geomorphic analysis of stream profiles with in situ-produced cosmogenic concentrations (10Be) in river sediments, to decipher the surface evolution of the AntiAtlas and the adjacent Siroua Massif. In the Anti-Atlas, the basin-wide denudation rates determined for the relictal part of the landscape range between 5 and 20 m Ma-1, consistent with rates estimated from the volume of volcanics eroded from the Siroua Massif during the last 12 - 10 Ma (10 to 20 m Ma-1). The close agreement of short- and long-term erosion rates suggests a steady state landscape.Our results demonstrate the main role of rock-type on sustaining post-orogenic landscape. Specifically, we find a striking correlation between erosion rates and normalized channel steepness per different rock-types. This allows estimating the erodibility within a narrower range of values (10-7 - 10-4) as a function of the reference concavity values of the river network.

Published
2021

14. Quantifying the dynamic topography through a combination of basin-averaged erosion rates and geomorphic analysis from the Anti Atlas and Western Meseta (Morocco) transient landscape

Author

Abderrahim Essaifi, Ahmed Yaaqoub, Valery Guillou, Paolo Ballato, Lionel Siame, Laëtitia Léanni, Romano Clementucci, and Claudio Faccenna

Subjects
Ocean surface topography, Atlas (topology), Erosion, Transient (oscillation), Structural basin, Geomorphology, Geology
Abstract

The topography of the Atlas-Meseta system (Morocco) is the result of Late Cenozoic rejuvenation related to mantle-driven uplift. This recent, large-scale dynamic uplift is testified by the occurrence of uplifted shallow-water marine deposits in the Middle Atlas Mountains and in the Western Meseta, indicating that surface uplift must have started after the Late Miocene (Messinian) at rates of 0.1 to 0.2 mm yr-1. This recent pulse is still recorded by transient river networks and by the presence of uplifted relict landscape. In particular, in the Anti Atlas and Western Maroccan Meseta, the lack of significant Cenozoic crustal shortening and the occurrence of several hundred of meters of mantle-driven uplift, offers the possibility to investigate magnitude, timing and rates of deep-seated uplift. In this study we have combined geomorphic analysis of stream profiles with in situ-produced cosmogenic concentrations (10Be, 26Al) in river sediments and bedrock surfaces (corresponding to relict landscape upstream of knickpoints), in order to decipher the uplift history. Our catchment-mean erosion rates allow us to quantitatively constrain the transient state of landscape and hence to unravel the contribution of regional surface uplift on mountain building processes in Morocco during the Plio-Quaternary.

Published
2020
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15. Evolution tardi-cénozoïque de la vallée de l'Ariège (Pyrénées) : apport des datations 26Al/10Be et 10Be/21Ne de sédiments intrakarstiques

Author

Valery Guillou, Didier Bourlès, Laurent Zimmermann, Audry Bourdet, Alexis Laffitte, Laëtitia Léanni, Bouchaïb Tibari, Aster Team, Amandine Sartégou, Pierre-Henri Blard, Régis Braucher, Patrick Sorriaux, 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), 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), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Glaciologie [Bruxelles], Université libre de Bruxelles (ULB), Géosciences Environnement Toulouse (GET), 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), RGF PyrénéesINSU, Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), and 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)

Subjects
010504 meteorology & atmospheric sciences, Fluvial, 010502 geochemistry & geophysics, Neogene, 01 natural sciences, Incision rates, Karst geomorphology, Paleontology, Cave, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Glacial period, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Cosmogenic nuclide, 0105 earth and related environmental sciences, Earth-Surface Processes, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, 10Be, Cosmogenic burial dating, Pyrenees, 15. Life on land, Karst, 26Al, 21Ne, Alluvium, Cave deposits, Cenozoic, Geology
Abstract

International audience; Despite increasing knowledge on the orogenic phases of the Pyrenees, the Neogene evolution of the range remains poorly constrained. The central Pyrenees, particularly the Ariège River valley and its terrace systems and glacial extensions, are key to reconstructing Pyrenean evolution during the Neogene. However, few terrace relics remain on the piedmont edges. To overcome this limitation and temporally extend the dataset obtained from terraces, we focus on alluvium-filled horizontal epiphreatic passages developed in limestone karstic networks. These landforms record the transient position of former local base levels during the process of valley deepening, similar to fluvial terraces. The alluvium fills of the studied caves in the Tarascon-sur-Ariège area, in the transition zone between the upper range and the piedmont, therefore enable the reconstruction of the geodynamic evolution of the Ariège River valley. All studied caves are developed on at least eight levels. Based on burial durations determined by 26Al/10Be and 10Be/21Ne terrestrial cosmogenic nuclide dating of samples from epiphreatic levels, our results indicate Langhian to Messinian (~13–5 Ma) incision rates averaging 48 m Myr−1. However, the obtained record does not allow us to accurately retrace the Pliocene evolution of the area due to the lack of known caves at corresponding levels. Moreover, raised local base levels during glacial phases both make the record more complex and call into question the methodological approach in terms of potential internal sediment remobilization and mixing related to implied re-flooding periods.

Published
2020
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16. How to reconcile OSL and TCN data: the potential of high-resolution sampling on the Choushui Tableland (West Central Taiwan)

Author

Brice Lebrun, Magali Rizza, Valery Guillou, Lionel Siame, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), and 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)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Environmental science, Sampling (statistics), High resolution, Physical geography, ComputingMilieux_MISCELLANEOUS
Abstract

The determination of fault slip rate is often inferred from dating of Quaternary, deformed geomorphological surfaces affected by fault activity. For this reason, cosmogenic and luminescence methods now are widely applied to date the emplacement of geomorphic markers, but each method relates to different geomorphic processes. While the Terrestrial Cosmogenic Nuclides (TCN) method generally dates the exposure duration of the rock surface to cosmic rays, the Optically Stimulated Luminescence (OSL) method provides burial duration of the sediment after deposition. Age differences between these two methods may relate to the erosion-transport-deposition and aggradation processes experienced by the sediment prior its final deposition but combined may provide new insights into the processes affecting alluvial landforms.Our case study is located in the Western Foothills, south of the Choushui River (Central Taiwan). There, slip on the Changhua blind thrust fault has caused the eastward tilt of a wide flight of fluvial terraces but slip rates on frontal faults are still debated due to large epistemic uncertainties in dating alluvial surfaces with OSL and TCN methods. To achieve a finer chronology of the deposits, a high-resolution sampling strategy has been deployed leading to a direct and unique comparison between OSL and TCN dating methods. Taking advantage of a natural exposure, we collected 10 samples for 10Be dating completed by 5 OSL samples along a 7 m depth profile. The depth distribution of 10Be concentrations show a complex depositional history with at least two depositional sequences, modelled to be older than ~38.7 ka.As previous work has shown the difficulties of OSL dating in Taiwan, particular attention has been paid to luminescence characteristics of quartz and potential dosimetry issues. Our OSL analysis are in good agreement with 10Be and previous 14C dating and also reveal three depositional units, dated between ~9 ka and ~66 ka, that are evidenced by different OSL signal characteristics and variations in dosimetry.This study shows that it is informative to have an exhaustive, detailed, and direct comparison between dating methods on a single depth profile to discuss the geomorphic processes and allow a more detailed understanding of the long-term rates of the Changhua Fault.

Published
2020

17. Limited influence of climatic gradients on the denudation of a Mediterranean carbonate landscape

Author

Didier Bourlès, Karim Keddadouche, Vincent Godard, Magali Rizza, Georges Aumaître, Lucilla Benedetti, Valery Guillou, Franck Thomas, Olivier Bellier, Vincent Ollivier, Fabrice Hollender, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), Laboratoire méditerranéen de préhistoire Europe-Afrique (LAMPEA), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), ECCOREV Research Federation, INSU-CNRS, Cashima Research Project - CEA Cadarache, Cashima Research Project - ITER Organisation, CEA, Conseil Regional PACA, INSU/CNRS, ANR through the 'Projets thematiques d'excellence' programme for the 'Equipements d'excellence' ASTER-CEREGE action, IRD, French Government 'Investissements d'Avenir' programme of the French National Research Agency (ANR) through the A*MlDEX project [ANR-11-IDEX-0001-02, ANR-11-LABX-0061], and 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)

Subjects
Mediterranean climate, landscape evolution, denudation rates, 010504 meteorology & atmospheric sciences, Weathering, precipitation, cosmogenic nuclides, 010502 geochemistry & geophysics, 01 natural sciences, carbonate, chemistry.chemical_compound, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Precipitation, Cosmogenic nuclide, climate, ComputingMilieux_MISCELLANEOUS, Holocene, 0105 earth and related environmental sciences, Earth-Surface Processes, 15. Life on land, Tectonics, chemistry, Denudation, 13. Climate action, Carbonate, Physical geography, Geology
Abstract

International audience; The dynamics of carbonate-dominated landscapes is still debated, and first-order questions pertaining to the respective importance of chemical and mechanical weathering processes or the influence of climatic variability on denudation rates are largely open. To address these issues, we investigate the denudation pattern across a climatic gradient in Provence, SE France. We focused on a series of major carbonate mountain ranges with elevation spanning 200 to 2000 m and associated with >2-fold variations in mean annual temperature and precipitation. We collected 25 samples from 10 different mountain ranges and quantified denudation rates through the measurement of their Cl-36 concentrations in order to explore tectonic and climatic controls on these carbonate landscapes evolution. We observe that most of our samples experience denudation rates in the 30-60 mm/ka range (averaged over 5 to 40 ka), with no evident dependence on variations of mean annual temperature or precipitation. One range (Lure mountain) stands out as a significant outlier, with much higher denudation rates (>100 mm/ka) than adjacent sites (Ventoux mountain) at the same elevation and experiencing similar present-day environmental conditions. We explore in details the climatic, tectonic and geomorphological contexts of these two ranges in order to understand the reasons for this apparent 3-fold difference in denudation rates. A regionally-documented major Holocene hillslope destabilization event appears to be a likely candidate to explain the observed lower Cl-36 concentrations at the top of the Lure mountain. At longer wavelengths, our regional dataset shows no clear control of modem precipitation gradients on denudation rates, consistent with previous observations in landscapes underlain by other lithologies.

Published
2018
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18. Rate of Slip From Multiple Quaternary Dating Methods and Paleoseismic Investigations Along the Talas‐Fergana Fault: Tectonic Implications for the Tien Shan Range

Author

James Jackson, Karim Keddadouche, Magali Rizza, G. E. Campbell, Andrew S. Carr, D.L. Bourles, Régis Braucher, D. McKenzie, Kanatbek Abdrakhmatov, Valery Guillou, Richard Walker, Georges Aumaître, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), Bullard Lboratories, Department of Earth Sciences [Cambridge, UK], University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), NERCNERC Natural Environment Research Council [EwF_NE/J02001X/1_1], ESRCEconomic & Social Research Council (ESRC) [EwF_NE/J02001X/1_1], NERC Radiocarbon Facility [NRCF010001, 1763.1013], French National Research Agency (ANR)French National Research Agency (ANR) [ANR-10-EQPX-20], National Program TelluS-ALEAS (SHEAR project) of CNRS/INSU, INSU/CNRSCentre National de la Recherche Scientifique (CNRS), ANR through the 'Projets thematiques d'excellence' program for the 'Equipements d'excellence' ASTERCEREGE action, IRD, 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), and 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)

Subjects
010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Paleoseismology, Slip (materials science), Active fault, 010502 geochemistry & geophysics, 01 natural sciences, tien shan, Geochemistry and Petrology, tectonic geomorphology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, active faults, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, Thermoluminescence dating, Alluvial fan, Tectonics, cosmogenic dating, Geophysics, Surface exposure dating, luminescence dating, Quaternary, paleoseismology, Geology, Seismology
Abstract

International audience; The 400-km-long Talas-Fergana Fault is one of a series of major right-lateral strike-slip faults that cross the Tien Shan Range. This fault has been recognized as active in the late Holocene and accommodates part of the deformation induced by the ongoing Indo-Asian collision. The kinematics and the role of this strike-slip fault are poorly understood with no large earthquakes reported in the instrumental or historical catalogs, and no well-constrained geological slip-rate estimates. Here we used high-resolution satellite imagery to present a first detailed analysis of the fault segmentation. We identified nine geometric segments based on strike variations for the Talas-Fergana Fault. Along the Kyldau segment, through morphological analyses of an offset alluvial fan and the application of multiple dating methods (Be-10, Al-26, Cl-36, luminescence, and radiocarbon), we calculated a late Quaternary slip rate ranging from 2.2 to 6.3 mm/year. This rate is higher than the geodetic measurements, but the discrepancy can be partly explained if the Talas-Fergana Fault accommodates shortening by counterclockwise rotation around a vertical axis. Paleoearthquakes identified by trenching indicate that at least two primary surface ruptures (and possibly a third) occurred in the past 3,800 years, and that no large earthquake has ruptured the Kyldau segment since at least 420 years B.P. (possibly within the last 2,700 years), making this fault segment a potential candidate to generate an earthquake with M > 7 in the near future.

Published
2019
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19. Design and performance of an automated chemical extraction bench for the preparation of 10Be and 26Al targets to be analyzed by accelerator mass spectrometry

Author

Valery Guillou, Laëtitia Léanni, Georges Aumaître, Régis Braucher, Karim Keddadouche, Mélanie Baroni, Didier Bourlès, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), 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), and 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)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Nuclear and High Energy Physics, 010504 meteorology & atmospheric sciences, business.industry, [SDE.MCG]Environmental Sciences/Global Changes, Sample processing, Extraction (chemistry), Labview software, Stable element, 010502 geochemistry & geophysics, 01 natural sciences, automated bench, Environmental science, cosmogenic preparation, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Cosmogenic nuclide, Process engineering, business, labview, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Instrumentation, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Accelerator mass spectrometry
Abstract

International audience; The growing number of studies based on data provided by the accelerator mass spectrometry (AMS) technique from increasingly diverse matrices implies that developing very effective and reproducible sample processing techniques is crucial to meet the demand generated. After being dissolved, the isolation of the cosmogenic nuclide to be measured and its chemical purification imply complex processes throughout successive stages The presented automatic system was designed to perform the final steps of the Be-10 and Al-26 chemical extraction protocol from natural matrices (sediments, pure mineral phases, ...), previously purified, decontaminated and dissolved in the case of in situ-produced cosmogenic nuclides, or leached or dissolved in the case of meteoric cosmogenic nuclides. Driven by Labview software, the developed automatic system, in addition to freeing the operator from tedious tasks, allows reproducibly processing simultaneously up to eight samples of different volumes in roughly 40 min. This article presents the design of the automated extraction bench and its performance based on the recovery efficiency of the stable element and the reproducibility of the measurements of the cosmogenic nuclide concentrations by AMS.

Published
2019
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20. River incision and migration deduced from 36Cl cosmic-ray exposure durations: The Clue de la Cerise gorge in southern French Alps

Author

Carole Petit, Régis Braucher, Yann Rolland, Didier Bourlès, Valery Guillou, Vincent Petitperrin, 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]), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), 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), and 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)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Bedding, [SDE.MCG]Environmental Sciences/Global Changes, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Cosmic ray, 010502 geochemistry & geophysics, 01 natural sciences, Paleontology, Denudation, Cliff, Younger Dryas, Glacial period, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Cosmogenic nuclide, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes, River incision
Abstract

International audience; We estimate recent (20 ka) incision and lateral migration rate on a spectacular ~N-S striking gorge cross-cutting N-dipping limestones in a fold-and-thrust belt of the external Southern French Alps. Upstream of the gorge, the river makes a right angle turn and follows the limestone surface parallel to the bedding direction (~EW). Eighteen samples were gathered along two vertical river polished profiles and three others on the denuded north-dipping surface layer, in order to determine river incision and lateral migration timing and rates. Surface age exposures of polished river cliff and bedding surface have been obtained from 36Cl cosmogenic nuclide dating and allow us to constrain the rate of vertical incision and of surface denudation of the Jurassic limestone layer. Fifteen 36Cl exposure ages have been obtained and range from ~21 ka to ~3 ka. Samples clearly define two age/height linear trends, which slopes correspond to incision rates of 1 and 0.3 mm/yr, respectively. The transition from low to high incision rate occurs at about ~12 ka, i.e. during the Younger Dryas glacial phase. Data also indicate that the vertical incision of the N-S branch of the gorge is coeval with the lateral (northward) river migration of its E-W branch associated with the denudation of the limestones surface. Extrapolating incision rates deduced from 36Cl exposure ages through time suggests that the incision of the Clue and denudation of the Jurassic limestones started about 500–600 ka ago.

Published
2019
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21. Authigenic 10 Be/ 9 Be ratio signatures of the cosmogenic nuclide production linked to geomagnetic dipole moment variation since the Brunhes/Matuyama boundary

Author

Didier Bourlès, Valery Guillou, Lucie Menabreaz, Quentin Simon, Luc Beaufort, Franck Bassinot, Nicolas Thouveny, Jean-Pierre Valet, Sandrine Choy, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), Institut de Physique du Globe de Paris (IPGP), 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), 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), 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), 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 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 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)-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), and 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)

Subjects
Paleomagnetism, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Excursion, Geophysics, Authigenic, 010502 geochemistry & geophysics, 01 natural sciences, Dipole, Amplitude, Earth's magnetic field, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Cosmogenic nuclide, Magnetic dipole, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Geomagnetic dipole moment variations associated with polarity reversals and excursions are expressed by large changes of the cosmogenic nuclide beryllium-10 (10 Be) production rates. Authigenic 10 Be/ 9 Be ratios (proxy of atmospheric 10 Be production) from oceanic cores therefore complete the classical information derived from relative paleointensity (RPI) records. This study presents new authigenic 10 Be/ 9 Be ratio results obtained from cores MD05-2920 and MD05-2930 collected in the west equatorial Pacific Ocean. Be ratios from cores MD05-2920, MD05-2930 and MD90-0961 have been stacked and averaged. Variations of the authigenic 10 Be/ 9 Be ratio are analyzed and compared with the geomagnetic dipole low series reported from global RPI stacks. The largest 10 Be overproduction episodes are related to dipole field collapses (below a threshold of 2 × 10 22 Am 2) associated with the Brunhes/Matuyama reversal, the Laschamp (41 ka) excursion, and the Iceland Basin event (190 ka). Other significant 10 Be production peaks are correlated to geomagnetic excursions reported in literature. The record was then calibrated by using absolute dipole moment values drawn from the Geomagia and Pint paleointensity value databases. The 10 Be-derived geomagnetic dipole moment record, independent from sedimentary paleomagnetic data, covers the Brunhes-Matuyama transition and the whole Brunhes Chron. It provides new and complementary data on the amplitude and timing of millennial-scale geomagnetic dipole moment variations and particularly on dipole moment collapses triggering polarity instabilities.

Published
2016
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22. The Dinaric fault system: Large-scale structure, rates of slip, and Plio-Pleistocene evolution of the transpressive northeastern boundary of the Adria microplate

Author

Magali Rizza, Karim Keddadouche, Petra Jamšek Rupnik, Didier Bourlès, Andrej Gosar, Valery Guillou, Maurice Arnold, Georges Aumaître, Adrien Moulin, Jean-François Ritz, and Lucilla Benedetti

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Pleistocene, Plio-Pleistocene, Slip (materials science), Active fault, Kinematics, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Geochemistry and Petrology, Scale structure, Digital elevation model, Seismology, Geology, 0105 earth and related environmental sciences
Abstract

Located at the northeastern corner of the Adria microplate, the Alps-Dinarides junction represents a key region for understanding how the Adria microplate interacts with stable Europe. However, little is known on how the present-day deformation imposed by the rotation of the Adria microplate is absorbed across the Dinarides. Using morphotectonic analysis based on satellite and aerial images, accurate topographical maps, and digital elevation models combined with field investigations, we mapped in detail the three main active faults of the Northern Dinarides. Geomorphic and geological cumulative displacements ranging from a few meters to several kilometers have been identified on those faults and dated for the most recent ones using 36 Cl exposure dating. Those results yielded a total right-lateral motion of 3.8 ± 0.7 mm/yr oriented N317. Comparing our results with the motion expected from Adria rotation models suggests that the Northern Dinarides absorbs most of the predicted Adria-Eurasia motion, thus representing the eastern boundary of the microplate. However, a significant E-W component is lacking, suggesting that part of the stress imposed by the microplate rotation is transferred farther to the east. Finally, bounds placed on the Plio-Pleistocene kinematics confirm that faulting onset occurred during the Early Pliocene and evidence a significant kinematic change at the Early/Middle Pleistocene boundary.

Published
2016
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23. Application of the authigenic 10Be/9Be dating method to Late Miocene–Pliocene sequences in the northern Danube Basin (Pannonian Basin System): Confirmation of heterochronous evolution of sedimentary environments

Author

Natália Hudáčková, Régis Braucher, Didier Bourlès, Samuel Rybár, Michal Kováč, Valery Guillou, and Michal Šujan

Subjects
Global and Planetary Change, 010504 meteorology & atmospheric sciences, Pleistocene, Authigenic, Structural basin, Late Miocene, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Sedimentary depositional environment, Paleontology, Sedimentary rock, Alluvium, Progradation, Geology, 0105 earth and related environmental sciences
Abstract

Authigenic 10 Be/ 9 Be dating method was applied to lacustrine, deltaic and alluvial sequences of the northern Danube Basin (Pannonian Basin System), to bridge the insufficiency of geochronological data for the Late Miocene to Pliocene period. The measurements of 51 samples (both lacustrine and floodplain), ranging from 11.6 to 0.95 Ma are consistent with the existing magnetostratigraphic and biostratigraphic data standing mainly on the evolution degree of endemic mollusk fauna, mammals and dinocysts. This agreement confirms our assumption that the incoming beryllium fluxes remained constant over the studied time period and thus that the two initial 10 Be/ 9 Be ratios determined in actual Holocene/Late Pleistocene sediments (lacustrine and floodplain) are valid for these environments. The obtained ages indicate gradual progradation of the deltaic depositional systems across the Danube Basin with a clear time-transgressional character, replacing basin floor and shelfal environments. Deltaic sedimentation occurred firstly in the north at foothills of the Western Carpathians from 11.0 Ma, and changed to the alluvial environment after 10.5 Ma. At the same time (~ 10.5 Ma), the paleo-Danube deltaic system draining the Eastern Alps entered the study area from the Vienna Basin situated on the West. Later, the deltaic systems were merged in the central part of the basin and reached its southeastern margin at ~ 9.4 Ma. Regression of the Lake Pannon from the southernmost part of the study area is evidenced after 8.7 Ma. Alluvial deposition of meandering rivers lasting until 6.0–5.0 Ma followed and was interrupted by the early Pliocene basin inversion. Sedimentation of braided streams took place during the late Pliocene and Pleistocene, reflecting uplift of mountains surrounding the basin margins. This study documents the powerful potential of the authigenic 10 Be/ 9 Be dating method and its reliability in a basin with complicated tectonic and sedimentary history. It demonstrates that this method can effectively be applied to lacustrine and floodplain deposits and to samples from outcrops as well as boreholes.

Published
2016
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24. The Last Glacial Maximum extent of the Scandinavian Ice Sheet in the Valday Heights, western Russia: Evidence from cosmogenic surface exposure dating using 10Be

Author

Aleksandr Gorlach, Didier Bourlès, Vincent Rinterknecht, Katrin Kalla, Tiit Hang, Volli Kalm, Aster Team, Dmitry Subetto, Valery Guillou, Laëtitia Léanni, Marko Kohv, 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), Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia, University of Tartu, 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), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Panthéon-Sorbonne (UP1), 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), and 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)

Subjects
010506 paleontology, Archeology, 010504 meteorology & atmospheric sciences, Ice stream, Late weichselian, 01 natural sciences, Natural (archaeology), LGM NW, Scandinavian ice sheet, Glacial period, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Global and Planetary Change, geography, Russia Valday, geography.geographical_feature_category, heights, Geology, Last Glacial Maximum, Cosmogenic 10Be, Ice-sheet model, Surface exposure dating, [SDU]Sciences of the Universe [physics], Physical geography, Ice sheet, Chronology
Abstract

International audience; Recent synoptic studies have summarized the former spatial extent and chronology of the last Scandinavian Ice Sheet (SIS) and provide exceptional compilations of empirical datasets. The latter represent the primary source of information for the modelling community to test and develop thermomechanical ice sheet model, which are then further embedded into climatic and general circulation models. The Last Glacial Maximum (LGM) extent and chronology of the SIS across continental Europe were highlighted as being the least well-known thus generating the biggest uncertainties in the reconstruction of the ice sheet. While early geomorphological studies of the ice sheet marginal belts are numerous and detailed in western Russia, geochronological data are virtually inexistent. In an attempt to fill in this gap, we conducted a series of sampling campaigns for surface exposure dating using 10Be in the western and northwestern regions of Russia. We present here the first results from the Valday Heights where glacial deposits constitute well-preserved margins of the SIS. A total of 16 samples firmly establish the timing of the LGM in the Valday Heights at 20.1 ± 0.4 ka. The Valday Heights acted as a natural wall for the last maximum advance of the SIS during MIS2, constraining the eastern flank of the Ladoga-Ilmen-Lovat ice stream to the west of the hills. The Valday Heights were only overran by previously more extensive glacial advances as suggested by older exposure ages obtain on erratic boulders (31.2 ± 1.4 to 47.1 ± 1.5 ka) located east of the LGM limit.

Published
2018
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25. Evidence for a wide and gently dipping Main Himalayan Thrust in western Bhutan

Author

Didier Bourlès, Jampel Gyeltshen, Matthieu Ferry, Jean-François Ritz, Karim Keddadouche, Romain Le Roux-Mallouf, Georges Aumaître, Maurice Arnold, Valery Guillou, Rodolphe Cattin, Vincent Godard, and Dowchu Drupka

Subjects
Tectonics, Décollement, Geophysics, Denudation, 13. Climate action, Inversion (geology), Front (oceanography), General Earth and Planetary Sciences, Cosmogenic nuclide, Joint (geology), Geology, Seismology, Holocene
Abstract

The Main Himalayan Thrust (MHT) is the source of great earthquakes that have been documented along the range. Its geometry is a key parameter that influences accommodation of tectonic loading and earthquake magnitudes along the Himalayan Arc. Although seismic images are available for both the western and the central part of the range, this geometry remains poorly constrained for the Bhutanese Himalayas. Here we address this issue using a 10Be cosmogenic nuclides denudation transect across western Bhutan. We observe a wide low denudation rate domain between 50 km and 110 km from the front followed by a strong northward increase. Using a joint inversion of denudation rates, GPS data, and Holocene uplift rates, we interpret this pattern as a consequence of a flat-ramp transition along the MHT. Compared to central Nepal and Sikkim, this location of the ramp suggests a wider decollement, with implications for greater seismogenic potential of the MHT in western Bhutan.

Published
2015
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26. Morphological controls on the dynamics of carbonate landscapes under a mediterranean climate

Author

Magali Rizza, Esmaeil Shabanian, Nicolas Espurt, Franck Thomas, Vincent Godard, Olivier Bellier, Lucilla Benedetti, Valery Guillou, Team Aster, Stéphane Molliex, Vincent Ollivier, Fabrice Hollender, 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), Laboratoire méditerranéen de préhistoire Europe-Afrique (LAMPEA), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), 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]), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Géosciences Océan (LGO), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), 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), 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), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-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), and 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)

Subjects
Mediterranean climate, 010504 meteorology & atmospheric sciences, Range (biology), Geology, Weathering, 15. Life on land, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, Denudation, chemistry, Carbonate, Physical geography, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Geomorphology, 0105 earth and related environmental sciences
Abstract

International audience; The influence of the morphological setting on the denudation of carbonate landscapes and the respective contributions of mechanical and chemical weathering processes are still debated. We have addressed these questions by measuring 36Cl concentrations in 40 samples from the Luberon mountain, SE France, to constrain the denudation of various landscape elements. We observe a clear contrast between the local denudation rates from the flat summit surface, clustered around 30 mm/ka, and the basin‐average denudation rates across the flanks, ranging from 100 to 200 mm/ka. This difference highlights the transient evolution of the range, whose topography is still adjusting to previous uplift events. Such a pattern also suggests that carbonate dissolution is not the only driver of denudation in this setting, which appears to be significantly controlled by slope‐dependent processes.

Published
2017
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27. Monthly record of the Cl and Cl-36 fallout rates in a deciduous forest ecosystem in NE France in 2012 and 2013

Author

Julie Pupier, A.S.T.E.R. Team, Lucilla Benedetti, Valery Guillou, Didier Bourlès, Camille Bouchez, Elisabeth Leclerc, Yves Thiry, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), Agence Nationale pour la Gestion des Déchets Radioactifs (ANDRA), Agro-Systèmes Territoires Ressources Mirecourt (ASTER Mirecourt), Institut National de la Recherche Agronomique (INRA), 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 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)

Subjects
Canopy, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, biology, Stratigraphy, Chlorine-36, Geology, 010501 environmental sciences, 15. Life on land, Atmospheric sciences, biology.organism_classification, 01 natural sciences, Deciduous, 13. Climate action, Climatology, Earth and Planetary Sciences (miscellaneous), Ecosystem, Precipitation, Cosmogenic nuclide, Beech, Stratosphere, 0105 earth and related environmental sciences
Abstract

International audience; This study aims at determining the chlorine and chlorine-36 fallout rates in an experimental beech forest site located in NE France (48 degrees 31'55 `' N, 5 degrees 16'8 `' E). A monthly record of Cl and Cl-36 concentrations in rainfall samples collected above the canopy was performed during two years, from March 2012 to February 2014. The results show that the Cl concentrations mainly originate from sea-spray while the Cl-36 concentrations originate from the stratosphere and therefore present a seasonal dependency. Abrupt and important inputs of Cl-36 from the stratosphere indeed yield sharp increases of the recorded concentrations during the spring-summer. We also show that a too short sampling period might bias the determined Cl-36 fallout rate. To smooth the seasonal and sporadic bursts of Cl-36, a minimum of 6 months sampling period is required. A mean Cl-36 fallout rate of (77 +/- 21) atoms m(-2) S-1 can be deduced from our study, which is 45% higher than the modelled value. This discrepancy suggests more studies aiming at measuring the Cl-36 fallout rate worldwide are necessary. (C) 2016 Elsevier B.V. All rights reserved.

Published
2016
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28. Évolution morphogénique des Pyrénées orientales vue par les datations cosmogéniques de systèmes karstiques étagés

Author

Amandine Sartégou, Regis Braucher, Pierre-Henri Blard, Didier Bourlès, Marc Calvet, Patrick Sorriaux, Audry Bourdet, Yanni Gunnell, Bouchaib Tibari, Laurent Zimmermann, Christophe Bès, Jean-Claude Gayet, Gabriel Hez, Philippe Moreno, Valery Guillou, Georges Aumaitre, Karim Keddadouche, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), 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), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (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), Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Environnement Ville Société (EVS), École normale supérieure - Lyon (ENS Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), 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), Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École nationale supérieure d'architecture de Lyon (ENSAL)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École Nationale des Travaux Publics de l'État (ENTPE)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), École normale supérieure - Lyon (ENS Lyon)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and Sartégou, Amandine

Subjects
[SDU] Sciences of the Universe [physics], [SDE] Environmental Sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU.GM] Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU]Sciences of the Universe [physics], [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.TE] Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDE]Environmental Sciences, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

29. Pleistocene floodplain response to climatic forcing in the Ariège river catchment (Pyrenees, France): constraints from vertical 10Be profiles along glaciofluvial fill terraces and from related soil chronosequence features

Author

Magalie Delmas, Regis Braucher, Yanni Gunnell, Valery Guillou, Marie Calvet, Bourles, D. L., Unité de Recherche de Science du Sol d'Orléans (UR SOLS), Institut National de la Recherche Agronomique (INRA), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), Environnement Ville Société (EVS), École normale supérieure - Lyon (ENS Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Dynamique terrestre et planétaire (DTP), Université Toulouse III - Paul Sabatier (UT3), 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-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), Unité de Science du Sol (Orléans) (URSols), 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), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École nationale supérieure d'architecture de Lyon (ENSAL)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École Nationale des Travaux Publics de l'État (ENTPE)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), 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)-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), Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and 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)

Subjects
[SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, ComputingMilieux_MISCELLANEOUS, [SHS]Humanities and Social Sciences
Abstract

International audience

Published
2015

30. Constraints on Pleistocene glaciofluvial terrace age and related soil chronosequence features from vertical 10Be profiles in the Ariège River catchment (Pyrenees, France)

Author

Valery Guillou, Didier Bourlès, Régis Braucher, Yanni Gunnell, Marc Calvet, Magali Delmas, 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), 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), UMR 5600 EVS, Environnement Ville Société (EVS), École normale supérieure - Lyon (ENS Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Lyon (ENS Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-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), Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (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), École normale supérieure - Lyon (ENS Lyon)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Lyon (ENS Lyon)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD)

Subjects
Global and Planetary Change, geography, geography.geographical_feature_category, Paraglacial, Pyrenees, Beryllium 10, Fluvial, Last Glacial Maximum, Oceanography, Soil chronosequence, Terrace (geology), Aggradation, Interglacial, Cosmogenic, Depth profile, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Geomorphology, Climatic transition, Holocene, Terminal moraine, Geology, Alluvial terrace
Abstract

International audience; Sequences of alluvial fill-terraces record the long-term variation of fluvial transport regimes in response to Quaternary climatic changes. Through a production of increasingly precise chronologies, the broadening range of sediment dating methods in recent years has improved our understanding of correlations between alluvial dynamics and external forcing mechanisms. However, results in this field have mostly focused on periglacial and other mid-latitude settings. These may not readily apply to glaciofluvial environments, where alluvial regimes are narrowly dependent on the behavior of the adjacent ice-field. Here we constrain the ages of three glaciofluvial fill terraces based on five vertical 10Be age profiles in the Ariège River catchment, and produce a chronofunction of related contrasts in terrace tread topsoil characteristics. Each profile consists of 9 to 11 gravel samples collected over depths of 4.6 to 15 m. Terrace T1 (+ 15 m above the current riverbed) was sampled at ~ 4, 22 and 53 km downstream from the Last Glacial Maximum terminal moraine system of the Ariège outlet glacier. The profiles of T2 (+ 30 m) and T3 (+ 50 m) complete the data set. Beryllium-10 age profiles date the age of terrace tread abandonment as a result of fluvial incision. Results show that the incision of T1 occurred over a protracted period during the Last Termination, beginning ca. 17.5 View the MathML source–3.5+2.0 ka. Prior to this, aggradation occurred from MIS 4 to the global Last Glacial Maximum (LGM), i.e.,under maximum ice extent conditions, and lasted a few thousand years thereafter. The protracted influx of debris after the LGM was sustained by paraglacial storage release in the catchment and promoted by strong coupling between slope and channel processes. Fluvial incision of T1 occurred during the post-LGMcold-to-warm transition after a time (supported by paleobotanical evidence) when the vegetation cover was capable of ensuring catchment-wide slope stability. The wave of incision propagated downstream between 17.5 View the MathML source–3.5+2.0 ka (proximal profile) and 13.0 View the MathML source–0.5+3.5 ka (distal profiles). The exposure-age confidence intervals for T2 and T3 are much larger than for T1 (60–145 ka and 204–226 ka, respectively) but the data nonetheless allow the aggradation of T2 and T3 to be attributed to MIS 6 and MIS 8, respectively. The soil chronosequence permitted by the fill-terrace age sequence indicates that the Luvic Cambisols capping T1 formed after ~ 13–16 ka, i.e.,during the Holocene; (ii) the Haplic Luvisols capping T2 required at least ~ 130 ka, i.e.,two interglacials; and (iii) the deeply rubified, highly eluviated Luvisols capping T3 required at least ~ 250 ka, i.e.,at least three interglacials.

Published
2015
Full Text
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31. Isotope Dilution-AMS technique for Cl-36 and Cl determination in low chlorine content waters

Author

Pierre Deschamps, Valery Guillou, Georges Aumaître, Lucilla Benedetti, Didier Bourlès, Maurice Arnold, Julie Pupier, Karim Keddadouche, Camille Bouchez, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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 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 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)

Subjects
010504 meteorology & atmospheric sciences, Analytical chemistry, chemistry.chemical_element, Accelerator, Isotope dilution, 010502 geochemistry & geophysics, Mass spectrometry, 01 natural sciences, Chloride, Mass Spectrometry, Geochemistry and Petrology, Chlorine, medicine, Low chloride content, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Isotope, Chlorine-36, Geology, 6. Clean water, chemistry, 13. Climate action, Gravimetric analysis, Accelerator mass spectrometry, medicine.drug, Waters
Abstract

International audience; The cosmonuclide Cl-36 is relevant for hydrological applications due to its conservative chloride form. Cl-36 measurements are commonly performed by Accelerator Mass Spectrometry (AMS) while stable chlorine concentration measurements are usually performed by ion chromatography (IC). They can also be achieved by Isotope Dilution-Accelerator Mass Spectrometry (ID-AMS) which offers the advantage of the simultaneous determination of both Cl and Cl-36 contents. The range of applicability of this method has been assessed on rock samples but, to our knowledge, no experimental tests were conducted on water samples characterized by low chloride contents. This study aims at investigating the accuracy and precision of the ID-AMS method for such low chlorine water samples for which chloride and Cl-36 determinations remain highly challenging. First, internal and external errors were evaluated on the measured ratios and uncertainties on Cl and Cl-36 concentrations were assessed at +/- 5% and +/- 7% respectively using standard error propagation calculations. Focused on the 0.1 to 10 mg center dot L-1 concentration range, the Cl concentrations of thirty-five gravimetric standards were determined by ID-AMS leading to a 1:1 line (R-2 = 0.99) and a 1-sigma uncertainty on [Cl-] of +/- 5%, consistently with the propagated uncertainty. Finally, the optimal sample volume to reach accurate Cl-36 and Cl measurements with ID-AMS for water sample concentrations within the 0.1 to 10 mg center dot L-1 range has been theoretically estimated. (C) 2015 Elsevier B.V. All rights reserved.

Published
2015
Full Text
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32. Pleistocene floodplain response to climatic forcing in the Ariège River catchment (Pyrenees, France): constraints from vertical 10Be profiles in glaciofluvial fill terraces and from related soil chronosequence features

Author

Magali Delmas, Regis Braucher, Yanni Gunnell, Valery Guillou, Marc Calvet, Didier Bourles, 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), 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), Environnement Ville Société (EVS), École normale supérieure - Lyon (ENS Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-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), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD), 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), École normale supérieure - Lyon (ENS Lyon)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École nationale supérieure d'architecture de Lyon (ENSAL)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École Nationale des Travaux Publics de l'État (ENTPE)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Jean Moulin - Lyon 3 (UJML), and Université de Lyon-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon)

Subjects
[SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS, [SHS]Humanities and Social Sciences
Abstract

International audience

Published
2015

33. Datation d’alluvions par les nucléides cosmogéniques, forçages climatiques et variations sur 200 ka des styles fluviaux sur le piémont nord-pyrénéen

Author

Magalie Delmas, Regis Braucher, Valery Guillou, Marie Calvet, Yanni Gunnell, Bourles, D. L., Laboratoire d'étude des interactions entre sols, agrosystèmes et hydrosystèmes (LISAH), Institut National de la Recherche Agronomique (INRA), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), Dynamique terrestre et planétaire (DTP), Université Toulouse III - Paul Sabatier (UT3), 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-Centre National de la Recherche Scientifique (CNRS), Environnement Ville Société (EVS), École normale supérieure - Lyon (ENS Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), 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), 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)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École nationale supérieure d'architecture de Lyon (ENSAL)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-École Nationale des Travaux Publics de l'État (ENTPE)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), 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), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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)-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), Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)

Subjects
ComputingMilieux_MISCELLANEOUS, [SHS]Humanities and Social Sciences
Abstract

International audience

Published
2014

34. Normal faulting in the forearc of the Hellenic subduction margin: Paleoearthquake history and kinematics of the Spili Fault, Crete, Greece

Author

Dionisis Hristopulos, Lucilla Benedetti, Daniel Moraetis, Olivier Bellier, Valery Guillou, Vasiliki Mouslopoulou, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), 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), and 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)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, Surface exposure dating, Subduction, Pleistocene, Fault plane, Geology, Fault (geology), Normal fault, Forearc, Seismology
Abstract

International audience; The late-Cenozoic kinematic and late-Pleistocene paleoearthquake history of the Spili Fault is examined using slip-vector measurements and in situ cosmogenic (Cl-36) dating, respectively. The Spili Fault appears to have undergone at least three successive but distinct phases of extension since Messinian (similar to 7 Ma), with the most recent faulting resulting in the exhumation of its carbonate plane for a fault-length of similar to 20 km. Earthquake-slip and age data show that the lower 9 m of the Spili Fault plane were exhumed during the last similar to 16,500 years through a minimum of five large-magnitude (Mw > 6) earthquakes. The timing between successive paleoearthquakes varied by more than one order of magnitude (from 800 to 9000 years), suggesting a highly variable earthquake recurrence interval during late Pleistocene (CV = 1). This variability resulted to significant fluctuations in the displacement rate of the Spili Fault, with the millennium rate (3.5 mm/yr) being about six times faster than its late-Pleistocene rate (0.6 mm/yr). The observed variability in the slip-size of the paleoearthquakes is, however, significantly smaller (CV = 0.3). These data collectively suggest that the Spili Fault is one of the fastest moving faults in the forearc of the Hellenic subduction margin. (C) 2014 Elsevier Ltd. All rights reserved.

Published
2014
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35. Geomagnetic, cosmogenic and climatic changes across the last geomagnetic reversal from Equatorial Indian Ocean sediments

Author

Valery Guillou, Franck Bassinot, Fabien Dewilde, Alexandra Bouilloux, F. Lopes, Didier Bourlès, Sébastien Nomade, Jean-Pierre Valet, Nicolas Thouveny, Laboratoire de Géomagnétisme et Paléomagnétisme (LGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 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), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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)-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), 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), 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), 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 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), and 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)

Subjects
Astrochronology, δ18O, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geomagnetic pole, Authigenic, Geophysics, Geomagnetic reversal, Earth's magnetic field, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Remanence, [SDU]Sciences of the Universe [physics], Earth and Planetary Sciences (miscellaneous), Geomagnetic excursion, 14. Life underwater, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Geology, ComputingMilieux_MISCELLANEOUS
Abstract

High-resolution records of beryllium (10Be) production and relative paleointensity have been obtained across the Matuyama–Brunhes (M–B) reversal from the equatorial Indian Ocean (Maldives area). Both magnetic and geochemical analyses were performed from the same discrete samples to avoid any artificial depth offset. The authigenic 10Be concentrations were normalized with respect to 9Be in order to correct for potential environmental effects, while the relative paleointensity was derived from the remanent magnetization intensity after accounting for changes in magnetic concentration within the sediment. The relative paleointensity and the 10Be/9Be records are both characterized by large deviations, which culminate in the middle of the reversal. In contrast to most previous studies, and despite relative high deposition rate (4.7 cm/ka), we observed a perfect synchronism between the 10Be/9Be peak, the lowest value of relative paleointensity and the switch in direction, which indicates that bioturbation and post-depositional processes did not affect the magnetic record. This leaves no ambiguity for the stratigraphic position of the reversal located within Marine Isotopic Stage 19 as revealed by the planktonic δ18O record from the same core. The magnetic data depict a two-phase process with a precursory event preceding the rapid polarity switch, while only the second phase is present in the 10Be record, similarly to other low latitude records from the Indonesian area. Using an orbitally-tuned age model, we obtain an age of 772 ka ± 5 ka for the middle of the transition, while the precursory event occurred almost 20 ka before. We believe that the bimodal distribution emerging from the compilations of the ages of the M-B reversal results from the succession of these two events. Microtektites from the Australasian impact were found at 0.6 m below the transition ( 790 ka ± 5 ka B.P.) and confirm that this large event occurred 12 ka prior to the polarity transition. The distribution of tektite abundance was used to deconvolve the 10Be/9Be signal. The results confirm that the beryllium changes are concentrated during the transitional period, thus likely in presence of a multipolar geomagnetic field (or in the vicinity of a geomagnetic pole) that favored the penetration of cosmic rays and consequently increased the 10Be production. The absence of 10Be during the precursor indicates that the present site and the Indonesian ones were far away from a geomagnetic pole and that interlatitudinal atmospheric mixing was limited. The geomagnetic pole positions above the Indonesian sites during the precursor would thus be incompatible with the corresponding inclined dipolar field during this period, and suggest the dominance of low-degree harmonics.

Published
2014
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36. Liquid ∣liquid microinterface. Localization of the phase boundary by voltammetry and chronoamperometry; influence of the microchannel dimensions on diffusion

Author

Maurice L’Her, Sophie Peulon, Valery Guillou, Chimie, Electrochimie Moléculaires et Chimie Analytique (CEMCA), Université de Brest (UBO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Brestois Santé Agro Matière (IBSAM), and Université de Brest (UBO)

Subjects
Phase boundary, General Chemical Engineering, Analytical chemistry, 02 engineering and technology, Ablation, 010402 general chemistry, 01 natural sciences, Analytical Chemistry, Diffusion, Charge transfer, Chronoamperometry, Phase (matter), Interfaces (materials), Electrochemistry, [CHIM]Chemical Sciences, ITIES, Diffusion (business), Channel flow, Electrodes, Voltammetry, Microchannel, Aqueous solution, Chemistry, Polyimides, Liquids, 021001 nanoscience & nanotechnology, 0104 chemical sciences, 0210 nano-technology, Volatemmetry
Abstract

cited By 27; International audience; The contact between two liquid immiscible phases, aqueous solution and an organic solvent, dichloroethane, has been established through a microchannel drilled in the polyimide plate by photoablation. The dimensions of the channel, more precisely, the ratio of the diameter of the hole to the length equal to the thickness of the plate, are very critical parameters; the liquid introduction sequence is also important. The behavior is erratic when the organic phase fills the channel; this occurs only for long channels and when the solvent is introduced first. The electrochemistry is always stable and reproducible in the principal cases: when water is introduced before the solvent for a long channel or when the length of the channel is equal or shorter than its diameter whatever the liquid introduced first. The localization of the interface as well as the diffusion pattern have been studied by voltammetry and chronoamperometry of ClO4- transfer. When the interface is situated on the organic side of the channel, this asymmetrical situation, depending on the transfer direction, causes the liquid|liquid interface to behave like a recessed or an inlaid electrode. © 2001 Elsevier Science B.V. All rights reserved.

Published
2001
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37. Voltammetry of tetraalkylammonium picrates at water|nitrobenzene and water|dichloroethane microinterfaces; Influence of partition phenomena

Author

Sophie Peulon, Maurice L’Her, Valery Guillou, Vladimir Sladkov, Chimie, Electrochimie Moléculaires et Chimie Analytique (CEMCA), Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Brest (UBO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO), Analyse et environnement (LAE), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Cyclic voltammetry, General Chemical Engineering, Inorganic chemistry, Water|dichloroethane, Extraction, Micro liquid|liquid interface, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Analytical Chemistry, Nitrobenzene, Diffusion, chemistry.chemical_compound, symbols.namesake, Benzene, Cyclic voltammetry, Diffusion, Electrochemistry, Ethane, Extraction, Gibbs free energy, Solvents, Ion transfer, Micro liquid|liquid interface, Partition, Tetraalkylammonium picrates, Water|dichloroethane, Ammonium compounds, Electrochemistry, [CHIM]Chemical Sciences, ITIES, Voltammetry, Ammonium compounds, Ethane, Aqueous solution, Chemistry, 010401 analytical chemistry, Solvation, Benzene, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Gibbs free energy, Partition coefficient, Tetraalkylammonium picrates, Ion transfer, symbols, Solvents, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], 0210 nano-technology, Partition
Abstract

cited By 14; International audience; A microinterface between two immiscible phases (micro ITIES), established by a microchannel (internal diameter: 50 μm, length: 15 μm) drilled through a polyimide thin plate, gives reproducible voltammograms for the transfer of charges. As expected for such a microinterface, the regime for mass transport depends on the scan rate of voltammetry, low scan rates being characterized by steady-state currents corresponding to radial diffusion; faster sweeps give rise to conventional cyclic voltammograms, from linear diffusion. This has been used as an electrochemical method for the study of tetraalkylammonium picrates at interfaces between water and immiscible solvents (nitrobenzene, 1,2-dichloroethane). The partition of Me4NPi, Et4NPi, Pr4NPi, and Bu4NPi at the W∣NB and W∣DCE interfaces is clearly illustrated by voltammetry under steady-state conditions, allowing the measurement of Gibbs energies and interfacial potentials for the transfer of the ions from water to NB. When the organic solvent is DCE, the estimation of ionic interactions is risky in such a poorly dissociating medium; the microhole interface works well however, showing the influence of the medium on solvation of the cations and on the extraction of the picrates.

Published
2004
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