Tracking eolian dust with helium and thorium: Impacts of grain size and provenance

Autor: Marie Revel, Cristina Recasens, Sascha Serno, Youbin Sun, Jerry F. McManus, Aloys Bory, David McGee, Michael R. Kaplan, Samuel L Jaccard, Robert F. Anderson, Alejandra Borunda, Diego M. Gaiero, Gisela Winckler
Přispěvatelé: Massachusetts Institute of Technology (MIT), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Department of Earth and Environmental Engineering [New York], DFG-Leibniz Center for Earth Surface Processes and Climate Studies, Universität Potsdam, Case Western Reserve University [Cleveland], Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), CIGeS, FCEFyN, Universidad Nacional de Córdoba [Argentina], Haute École Pédagogique Berne-Jura-Neuchâtel (HEP Bejune), Haute Ecole Pédagogique du canton de Vaud (HEPL), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - 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 [France-Sud]), Hebei Key Laboratory of Molecular and Cellular Biology - Key Laboratory of Molecular and Cellular Biology of Ministry of Education - College of Life Science, Hebei University, Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-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)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), University of Potsdam = Universität Potsdam, Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), 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])
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Geochimica et Cosmochimica Acta
Geochimica et Cosmochimica Acta, Elsevier, 2016, 175, pp.47-67. ⟨10.1016/j.gca.2015.11.023⟩
Geochimica et Cosmochimica Acta, 2016, 175, pp.47-67. ⟨10.1016/j.gca.2015.11.023⟩
ISSN: 0016-7037
Popis: Reconstructions of the deposition rate of windblown mineral dust in ocean sediments offer an important means of tracking past climate changes and of assessing the radiative and biogeochemical impacts of dust in past climates. Dust flux estimates in ocean sediments have commonly been based on the operationally defined lithogenic fraction of sediment samples. More recently, dust fluxes have been estimated from measurements of helium and thorium, as rare isotopes of these elements (He-3 and Th-230) allow estimates of sediment flux, and the dominant isotopes (He-4 and Th-232) are uniquely associated with the lithogenic fraction of marine sediments. In order to improve the fidelity of dust flux reconstructions based on He and Th, we present a survey of He and Th concentrations in sediments from dust source areas in East Asia, Australia and South America. Our data show systematic relationships between He and Th concentrations and grain size, with He concentrations decreasing and Th concentrations increasing with decreasing grain size. We find consistent He and Th concentrations in the fine fraction (38 degrees S). In the equatorial Pacific, He/Th ratios are much lower than in extratropical Pacific sediments or potential source areas measured as a part of this study (East Asia, South America, Australia) for reasons that are at present unclear, complicating their use as provenance tracers in this region. (C) 2015 Elsevier Ltd. All rights reserved.
Databáze: OpenAIRE
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