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Start Over Author "Didier Bourlès" Journal quaternary geochronology
10 results on '"Didier Bourlès"'

1. Dating late Holocene lava flows in Pico de Orizaba (Mexico) by means of in situ-produced cosmogenic 36Cl, lichenometry and dendrochronology

Author

Didier Bourlès, Leopoldo García-Sancho, Osvaldo Franco-Ramos, José Villanueva, Georges Aumaître, Jesús Alcalá-Reygosa, Lorenzo Vázquez-Selem, José J. Zamorano, Irene Schimmelpfennig, Karim Keddadouche, David Palacios, 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), Instituto de Neurociencias- CSIC, Universidad Miguel Hernández [Elche] (UMH), 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), DGAPA-UNAM, Spanish Ministry of Economy and Competitiveness [CGL2015-65813-R, CTM2015-64728-C2-1-R], UNAM-DGAPA-PAPIIT [IN105213, IN109216], INSU/CNRS, ANR through the 'Projets thematiques d'excellence' program for the 'Equipements d'excellence' ASTER-CEREGE action, IRD, 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
Juniperus monticola, 010504 meteorology & atmospheric sciences, Lava, [SDE.MCG]Environmental Sciences/Global Changes, Stratigraphy, Lava flows, 010502 geochemistry & geophysics, 01 natural sciences, law.invention, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, law, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Earth and Planetary Sciences (miscellaneous), Dendrochronology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Radiocarbon dating, Holocene, Rhizocarpon geographicum, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, biology, Landform, Geology, biology.organism_classification, Late Holocene, Lichenometry, Volcano, 13. Climate action, In situ-produced cosmogenic Cl-36, Physical geography, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; The knowledge of the eruptive history of volcanic centers allows for improving the evaluation of the related risks and hazards in populated areas, but substantially depends on the ability of dating the lava flows. However, traditional methods such as U-Th/He, 40 Ar-39 Ar, 40 K-40 Ar and radiocarbon dating are not always suitable. Therefore, an alternative approach based on the combination of in situ-produced 36 Cl based cosmic ray exposure dating, lichenometry and dendrochronology was tested on two lava flows (called Lava flow "A" and "B") from Pico de Orizaba (Mexico), previously attributed to 16th and 17th century eruptions, respectively. The presented results show that both lava flows are significantly older than their assumed 16th and 17th century ages. Regarding lava flow "A", the measured in situ-produced 36 Cl concentrations lead to a mean age of 3.03 ± 0.70 ka, while dendrochronology and lichenometry yield minimum ages of 834 and 1130 years, respectively. Regarding lava flow "B", the measured in situ-produced 36 Cl concentrations lead to a mean age of 1.45 ± 0.35 ka, whereas lichenometry gives a minimum age of ∼1000 years. Overall, this demonstrates that the combination of in situ-produced 36 Cl based cosmic ray exposure dating, lichenometry and dendrochronology has a considerable potential for dating purposes on young deposits and landforms, in particular on lava flows at high elevation sites.

Published
2018
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2. Toward the feldspar alternative for cosmogenic 10Be applications

Author

Didier Bourlès, Swann Zerathe, Pierre-Henri Blard, Julien Carcaillet, Georges Aumaître, Karim Keddadouche, Laurence Audin, Fabrizio Delgado, Régis Braucher, Carlos Benavente, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-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 des Sciences de la Terre (ISTerre), 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), Institut de Recherche pour le Développement (IRD), Université de Lorraine (UL)-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), 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]), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), 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
Mineral, 010504 meteorology & atmospheric sciences, Lithology, Stratigraphy, Trace element, Geochemistry, Mineralogy, Geology, Pyroxene, 010502 geochemistry & geophysics, Feldspar, 01 natural sciences, visual_art, Earth and Planetary Sciences (miscellaneous), visual_art.visual_art_medium, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Cosmogenic nuclide, Mafic, Quartz, 0105 earth and related environmental sciences
Abstract

International audience; The possibility of quantifying surface processes in mafic or volcanic environment using the potentialities offered by the in situ-produced cosmogenic nuclides, and more specifically by the in situ-produced Be-10, is often hampered by the rarity of quartz minerals in the available lithologies. As an alternative to overcome this difficulty, we explore in this work the possibility of relying on feldspar minerals rather that on quartz to perform in situ-produced Be-10 measurements in such environments. Our strategy was to cross-calibrate the total production rate of Be-10 in feldspar (P-10fsp) against the total production rate of He-3 in pyroxene (P-3px) by measuring He-3 and Be-10 in cogenetic pyroxene (He-3(px)) and feldspar (Be-10(fsp)). The samples were collected from eight ignimbritic boulders, exposed from ca 120 to 600 ka at elevations ranging from 800 to 2500 m, along the preserved rock-avalanche deposits of the giant Caquilluco landslide (18 degrees S, 70 degrees W), Southern Peru. Along with data recently published by Blard et al. (2013a) at a close latitude (22 degrees S) but higher elevation (ca. 4000 m), the samples yield a remarkably tight cluster of He-3(px) - Be-10(fsp) total production ratios whose weighted-mean is 35.6 +/- 0.5 (1 sigma). The obtained weighted mean He-3(px) - Be-10(fsp) total production ratio combined with the local He-3(py) total production rate in the high tropical Andes published by Martin et al. (2017) allows to establish a total SLHL Be-10 in situ-production rate in feldspar mineral (P-10fsp) of 3.57 +/- 0.21 at.g(-1).yr(-1) (scaled for the LSD scaling scheme, the ERA40 atm model and the VDM of Lifton, 2016). Despite the large elevation range covered by the whole dataset (800-4300 m), no significant variation of the He-3(px) - Be-10(fsp) total production ratios in pyroxene and feldspar was evidenced. As an attempt to investigate the effect of the chemical composition of feldspar on the total Be-10 production rate, major and trace element concentrations of the studied feldspar samples were analyzed. Unfortunately, giving the low compositional variability of our dataset, this issue is still pending. (C) 2017 Elsevier B.V. All rights reserved.

Published
2017
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3. Where now? Reflections on future directions for cosmogenic nuclide research from the CRONUS Projects

Author

Marc W. Caffee, Didier Bourlès, Adam M. Hudson, Meredith A. Kelly, Brent M. Goehring, Nathaniel A. Lifton, Robert C. Reedy, Tibor Dunai, Shasta M. Marrero, Fred M. Phillips, A. J. Timothy Jull, David C. Argento, John O. Stone, Kuni Nishiizumi, and John C. Gosse

Subjects
Hydrology, 010506 paleontology, Calibration (statistics), Stratigraphy, Geology, 010502 geochemistry & geophysics, 01 natural sciences, Industrial engineering, law.invention, Calculator, law, Consistency (statistics), Earth and Planetary Sciences (miscellaneous), Cosmogenic nuclide, 0105 earth and related environmental sciences
Abstract

The CRONUS-Earth and CRONUS-EU Projects have recently examined the reproducibility of cosmogenic nuclide measurements and the ability of cosmogenic-production models to fit high-quality global calibration data sets. In both cases, although results are adequate for present geochronological needs, they must be improved to meet future demands. We recommend that the cosmogenic-nuclide community embark on a continuing effort to understand the sources of the remaining model-versus-data discrepancy, and that in the meanwhile all cosmogenic ages be benchmarked against reference ages calculated in a consistent fashion. We also recommend that interlaboratory reference materials be routinely analyzed along with samples and blanks, that the results be tracked, and that methods of achieving consistency and precision in sample preparation and analysis be shared within the community. We also recommend additional organization of the community to facilitate the use of intercomparison materials, foster analytical improvements, oversee the evolution of the community age calculator, and synthesize ongoing calibration efforts.

Published
2016
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4. Corrigendum to 'Deciphering landscape evolution with karstic networks: A Pyrenean case study' [Quat. Geochronol. 43 (2018) 12–29]

Author

Amandine Sartégou, Karim Keddadouche, Laëtitia Léanni, Georges Aumaître, Laurent Zimmermann, Didier Bourlès, Pierre-Henri Blard, Régis Braucher, and Bouchaïb Tibari

Subjects
Paleontology, geography, geography.geographical_feature_category, Stratigraphy, Earth and Planetary Sciences (miscellaneous), Geology, Karst
Published
2020
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5. Surface exposure dating of the Veliki vrh rock avalanche in Slovenia associated with the 1348 earthquake

Author

Silke Merchel, Lucilla Benedetti, Didier Bourlès, Juergen M. Reitner, Blaz Repe, Irena Mrak, Régis Braucher, German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), 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)-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)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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
Earthquake, terrestrial cosmogenic nuclides (TCN), Stratigraphy, High velocity, Slovenia, Rock avalanche, Bed, Earth and Planetary Sciences (miscellaneous), Terrestrial cosmogenic nuclides (TCN), exposure dating, Geomorphology, ComputingMilieux_MISCELLANEOUS, 36Cl, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Exposure dating, geography, geography.geographical_feature_category, Bedrock, Fragmentation (computing), rock avalanche, Geology, Accelerator mass spectrometry, accelerator mass spectrometry, earthquake, Denudation, Surface exposure dating, [SDU]Sciences of the Universe [physics], 13. Climate action, Production rate
Abstract

International audience; Over 30 samples from bedrock and boulders from the Veliki vrh rock avalanche have been collected for surface exposure dating. The limestone rocks have been radiochemically treated to isolate and determine long-lived Cl-36 by accelerator mass spectrometry. It could be shown that the Veliki vrh rock avalanche from the KoSuta Mountain (Slovenia) event can be very likely linked to one of the major historical earthquakes in Europe happening on the 25th of January 1348. Taken into account independently determined denudation rates, inherited Cl-36 originating from pre-exposure at shallow depths (20-55 m) could be calculated. The high amount of inherited Cl-36, i.e. 17-46% of the total Cl-36, makes this site not suitable for a precise determination of the Cl-36 production rate as it was originally anticipated. Veliki vrh is a ``classic'' rock avalanche of high velocity. The slope failed in the upper part with a translational slide predominantly along the bedding planes, whereas dynamic fragmentation is the cause for further crushing of the material and the long runout. (c) 2014 Elsevier B.V. All rights reserved.

Published
2014
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6. The potential of historic rock avalanches and man-made structures as chlorine-36 production rate calibration sites

Author

Didier Bourlès, Silke Merchel, Jürgen M. Reitner, Vasily Alfimov, Max Bichler, and Régis Braucher

Subjects
geography, geography.geographical_feature_category, Calibration (statistics), Stratigraphy, Chlorine-36, Geochemistry, Sampling (statistics), Mineralogy, Geology, Fault (geology), Fault scarp, Surface exposure dating, Earth and Planetary Sciences (miscellaneous), Alluvium, Accelerator mass spectrometry
Abstract

Samples from three medieval rock avalanches from the French (Le Claps, Mont Granier) and Austrian Alps (Dobratsch) and a man-made structure, i.e. the Stephansdom in Vienna, have been analysed for in-situ produced 36Cl by accelerator mass spectrometry (AMS). All four sampling sites of independently known exposure duration turned out to be not appropriate as calibration sites for the determination of the 36Cl-production rate from Ca. Indeed, the determination of short exposure ages for dating rock avalanches and man-made structures by 36Cl is hindered dramatically by inheritance, especially for samples characterized by high natCl-concentrations. Generally, there are hints that the theoretical calculation of 36Cl-production from epithermal and thermal neutron-capture on 35Cl is highly underestimated in all existing models, thus, asking for particular precaution if working on high-Cl samples for any project. Hence, this work evidences that potential high inheritance, even for samples reasonably shielded before exhumation, has to be considered especially when dealing with recently exposed surfaces such as glacially polished rocks, alluvial terraces, fault scarps etc.

Published
2013
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7. Late Holocene seacliff retreat recorded by 10Be profiles across a coastal platform: Theory and example from the English Channel

Author

Grégoire M. Maillet, Anne Duperret, H. Anderson, Thomas Dewez, Didier Bourlès, Kevin Pedoja, Laëtitia Léanni, Stéphane Costa, Eric Lasseur, Vincent Regard, Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), 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), Institute of Arctic and Alpine Research (INSTAAR), University of Colorado [Boulder], Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Littoral, Environnement, Télédétection, Géomatique (LETG - Caen), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Université de Nantes (UN)-Université de Nantes (UN), Morphodynamique Continentale et Côtière (M2C), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire 'Paysages & Biodiversité' (PPF DS10), Université d'Angers (UA), Financement INSU : ASTER Financement SHOM/INSU : Reliefs de la terre : 'erosion des côtes rocheuses: de l'observation à la modélisation' Projet BRGM EVOLGEOM, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-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), Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-Université de Nantes (UN)-École pratique des hautes études (EPHE)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), 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), 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), Institute of Arctic Alpine Research [University of Colorado Boulder] (INSTAAR), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Géosciences Environnement Toulouse ( GET ), Institut de Recherche pour le Développement ( IRD ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Bureau de Recherches Géologiques et Minières (BRGM) ( BRGM ), Centre européen de recherche et d'enseignement de géosciences de l'environnement ( CEREGE ), Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Collège de France ( CdF ) -Institut National de la Recherche Agronomique ( INRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ), Department of Geological Sciences and Institute of Arctic & Alpine Research, University of Colorado Boulder [Boulder], Laboratoire Ondes et Milieux Complexes ( LOMC ), Université Le Havre Normandie ( ULH ), Normandie Université ( NU ) -Normandie Université ( NU ) -Centre National de la Recherche Scientifique ( CNRS ), Littoral, Environnement, Télédétection, Géomatique ( LETG - Caen ), Littoral, Environnement, Télédétection, Géomatique ( LETG ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Université d'Angers ( UA ) -Université de Nantes ( UN ) -École pratique des hautes études ( EPHE ) -Université de Brest ( UBO ) -Université de Rennes 2 ( UR2 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Caen Normandie ( UNICAEN ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), Morphodynamique Continentale et Côtière ( M2C ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Rouen Normandie ( UNIROUEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), and Université d'Angers ( UA )

Subjects
Tidal range, 010504 meteorology & atmospheric sciences, Stratigraphy, Beryllium-10, 010502 geochemistry & geophysics, 01 natural sciences, Downwearing, Cliff retreat, Earth and Planetary Sciences (miscellaneous), Deglaciation, Cliff, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, 14. Life underwater, Glacial period, Sea level, Holocene, Sea-level, 0105 earth and related environmental sciences, Shore, geography, [ SDU.STU.GM ] Sciences of the Universe [physics]/Earth Sciences/Geomorphology, geography.geographical_feature_category, Seacliff, Geology, Wave-cut platform, Oceanography, 13. Climate action, Shore platform, Physical geography
Abstract

International audience; We explore a new method for documenting the long term retreat rate of sea cliffs based on measurements and modeling of 10Be concentration transects across present-day shore platforms. The proposed forward numerical model relies on a scenario of sea level rise since the last deglaciation, and predicts the shape of 10Be concentration transects as a function of prescribed cliff recession and vertical coastal platform downwearing rates. Two independent transect features allow fitting the long-term recession rate model to field observations: a sharp 10Be concentration drop predicted at the former stationary location of the cliff during the last glacial period ~100 ka ago, and a characteristic dome shape whose magnitude is directly related to the recession rate of the cliff. A retreating chalk cliff site from the English Channel coast of France, at Mesnil Val, where the 7 m tidal range broadly exposes the shore platform, was selected to test the proposed method. Although retreat rates were too high to pinpoint the predicted 10Be concentration drop at the last glacial cliff position, the 10Be-concentration of the flints sampled across the shore platform are consistent with the expected dome shape. When modeled using the proper tidal range and proposed Holocene sea level rise history, the 10Be data yield a cliff retreat rate since the mid-Holocene of 11-13 cm/yr. This is consistent with a 30-year-long measurement record, strongly supporting the utility of the 10Be method.

Published
2012
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8. Interpreting scattered in-situ produced cosmogenic nuclide depth-profile data

Author

K. Le Dortz, Régis Braucher, M. Foroutan, Didier Bourlès, B. Meyer, Michel Sébrier, Lucilla Benedetti, H. Nazari, Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Research Institute for Earth Sciences, Geological Survey of Iran, Laboratoire de géologie de l'ENS (LGE), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), 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 - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), 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
010504 meteorology & atmospheric sciences, Stratigraphy, Sample (material), [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Sampling (statistics), Mineralogy, Geology, Cosmic ray, 010502 geochemistry & geophysics, 01 natural sciences, Deposition (aerosol physics), Denudation, Earth and Planetary Sciences (miscellaneous), Range (statistics), Alluvium, Cosmogenic nuclide, Geomorphology, 0105 earth and related environmental sciences
Abstract

Modelling the evolution of the concentration of in-situ produced cosmogenic nuclides as a function of depth (depth-profile) has been developed to allow determining both the exposure duration and the denudation rate affecting geomorphic features. However, material sampled through surficial deposits may exhibit an inherited component resulting from exposure to cosmic rays before deposition. In case of homogeneous inheritance, this inherited component may be estimated through sampling at increasing depths and subsequently subtracted. In case of variable inheritance, the measured concentrations are scattered and the random distribution of the depth-profile concentrations prevents modelling confidently a depth-profile and precludes constraining an exposure duration. Often observed in desert and endorheic regions, this greatly restricts the possibilities to determine an accurate abandonment age of alluvial surfaces in such environments. Provided the denudation is demonstrated negligible, a method for determining a more accurate range of minimum inheritance, hence a more accurate maximum abandonment age for a given alluvial surface, is proposed. This method, based on the rejuvenation of depth-profile samples, relies on the simple hypothesis that at least one of the depth-profile samples would be emplaced with no or negligible inherited component and on the obvious principle that none of analysed sample has been emplaced with a negative cosmogenic nuclide concentration. The method consists then in determining which of the measured depth-profile sample may have been emplaced with a null CRE concentration; i.e., with a zero inheritance value. This requires to calculate the in-situ duration of exposure needed to reach the concentration measured for each depth-profile sample and to retain the one that provides the smallest in-situ exposure duration. Several examples from alluvial surfaces of central Iran illustrate the profile rejuvenation method and highlight a variable inheritance ranging between 1.5 × 10 5 and 16.1 × 10 5 at/g (SiO 2 ) for terraces whose abandonment ages range from ten to several hundreds of ka.

Published
2012
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9. Erosion rates in an active orogen (NE-Taiwan): A confrontation of cosmogenic measurements with river suspended loads

Author

Hao-Tsu Chu, Didier Bourlès, Lionel Siame, Rou-Fei Chen, F. Derrieux, Régis Braucher, Jian-Cheng Lee, J. Angelier, Kuo-Jen Chang, and Vincent Godard

Subjects
Tectonics, Denudation, Stratigraphy, Earth and Planetary Sciences (miscellaneous), Erosion, Geology, Geomorphology
Abstract

The direct and feedback relationships between tectonics, climate and denudation are a matter of debate.

Published
2011
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10. Effect of density uncertainties in cosmogenic 10Be depth-profiles: Dating a cemented Pleistocene alluvial fan (Carboneras Fault, SE Iberia)

Author

Raimon Pallàs, Didier Bourlès, Régis Braucher, Ángel Rodés, Ximena Moreno, Eulàlia Masana, Departament de Geodinamica i Geofısica, Facultat de Geologia, Universitat de Barcelona (UB), 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)-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
010504 meteorology & atmospheric sciences, Pleistocene, Stratigraphy, Geochronology, Paleoseismology, 010502 geochemistry & geophysics, 01 natural sciences, Numerical model, Cosmic ray exposure dating, Earth and Planetary Sciences (miscellaneous), Geomorphology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Landform, Alluvial fan, Geology, Denudation, Cementation (geology), Calcrete, [SDU]Sciences of the Universe [physics], Alluvium
Abstract

Cosmonuclide depth-profiles can be used to calculate both the age of landforms and the rates at which erosion has affected them since their formation. Results are heavily dependent on the selection of the appropriate density of the material exposed to cosmic radiation. In materials where density has changed significantly through time, as in alluvial sediments affected by post-depositional calcrete cementation, the uncertainties in density must be accurately modelled to produce reliable results. We develop new equations for an accurate account of density uncertainties and to test the effect of density gain due to cementation processes. We apply them to two 10 Be depth-profiles measured in an alluvial fan deformed by the Carboneras Fault (SE Iberia). When a linear increase of density through time is considered, model results yield an age ranging from 200 ka to 1 Ma within 1 σ confidence level.

Published
2011
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