FN Archimer Export Format PT J TI Climate‐driven weathering shifts between highlands and floodplains BT AF Yu, Zhaojie Colin, Christophe Bassinot, Franck Wan, Shiming Bayon, Germain AS 1:1,2,3;2:4;3:5;4:1,2,3;5:6; FF 1:;2:;3:;4:;5:PDG-REM-GM-LGS; C1 Key Laboratory of Marine Geology and Environment, Institute of Oceanology Chinese Academy of Sciences Qingdao ,China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology Qingdao ,China Center for Ocean Mega‐Science Chinese Academy of Sciences Qingdao, China Laboratoire GEOsciences Paris‐Sud (GEOPS), UMR 8148, CNRS‐Université de Paris‐Sud Université Paris‐Saclay Orsay Cedex, France Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA‐CNRS‐UVSQ Université Paris‐Saclay Gif‐sur‐Yvette ,France IFREMER, Marine Geosciences Unit Plouzané ,France C2 CHINESE ACAD SCI, CHINA QNLM, CHINA CHINESE ACAD SCI, CHINA UNIV PARIS SUD, FRANCE CNRS, FRANCE IFREMER, FRANCE SI BREST SE PDG-REM-GM-LGS IN WOS Ifremer UPR copubli-france copubli-univ-france copubli-int-hors-europe copubli-sud IF 2.623 TC 12 UR https://archimer.ifremer.fr/doc/00632/74434/74154.pdf LA English DT Article DE ;climate change;continental weathering;highlands and floodplains;carbon cycle;Himalaya AB Chemical weathering of silicate rocks on continents is thought to have played an important role in the evolution of past atmospheric carbon dioxide over geologic timescales. However, the detailed links between continental weathering and climate change over shorter timescales, and their potential impact on sediment records deposited in the ocean, remain poorly understood. Here, we present clay mineralogy and strontium‐neodymium isotopic data for marine sediment records from the Northern Indian Ocean, with the aim of investigating the weathering response of large Himalayan river basins to orbital and millennial climate forcing. We show that past glaciated episodes of the late Quaternary corresponded to periods of increased physical erosion, associated with the preferential export of illite and chlorite assemblages from the Himalayan highlands having relatively radiogenic Sr isotopic signatures. In contrast, the warm periods of enhanced monsoon rainfall coincided with the transport of intensively weathered smectite‐dominated soils derived from the floodplains, characterized by lower 87Sr/86Sr signatures. This finding suggests that the short‐term climatic variability over Late Quaternary timescales was accompanied by concomitant changes between high mountain‐ versus floodplain‐dominated weathering regimes, with possible impact on the nature of weathered rocks and, as a consequence, on the carbon cycle. PY 2020 PD JUN SO Geochemistry Geophysics Geosystems SN 1525-2027 PU American Geophysical Union (AGU) VL 21 IS 7 UT 000557248500032 DI 10.1029/2020GC008936 ID 74434 ER EF