Holocene hydroclimate variability along the Southern Patagonian margin (Chile) reconstructed from Cueva Chica speleothems

• Published in: Global and Planetary Change
• Main Authors: Nehme, C., Todisco, D., Breitenbach, S.F.M., Couchoud, Isabelle, Marchegiano, M., Peral, M., Vonhof, H., Hellstrom, J., Tjallingii, R., Claeys, P., Borrero, L., Martin, F.
• Other Authors: Identité et Différenciation de l’Espace, de l’Environnement et des Sociétés (IDEES), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire Homme et Société (IRIHS), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Vrije Universiteit Brussel (VUB), University of Northumbria at Newcastle United Kingdom, 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), Analytical, Environmental and Geo- Chemistry, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, School of Earth Sciences Melbourne, Faculty of Science Melbourne, University of Melbourne-University of Melbourne, German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Universidad de Buenos Aires Buenos Aires (UBA), Centro de Estudios del Hombre Austral, Universidad de Magallanes (UMAG)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Holocene; Speleothems; Stable isotopes; Southern westerly winds; Patagonia; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Antarctic; Antarctic Peninsula; Chica; Cueva; Pacific; Southern Ocean; The Antarctic; Antarc*
• Online Access: https://hal.science/hal-04287379; https://hal.science/hal-04287379/document; https://hal.science/hal-04287379/file/SSRN_id4172978.pdf; https://doi.org/10.1016/j.gloplacha.2023.104050

International audience Patagonia is ideally situated to reconstruct past migrations of the southern westerly winds (SWWs) due to itssoutherly maritime location. The SWWs are an important driver of Southern Ocean upwelling and their strengthand latitudinal position changed during the Holocene, leading thus to different responses of the vegetation topast climate changes along the Chilean continental margin. A new speleothem record from Cueva Chica (51◦S) isinvestigated to reconstruct past climatic changes throughout the Holocene in conjunction with other marine andpaleoenvironmental records of the region and better constrain the regional paleoclimatic evolutions of SWWs.Samples comprising both a flowstone core and a stalagmite were radiometrically dated (U–Th & 14C) toconstruct age-depth models for the highly-resolved proxy profiles (δ13C, δ18O, chemical composition). TheCueva Chica record provides a highly-resolved isotopic and elemental curves for the last 12 ka, albeit with ahiatus from 5.8 to 4 ka BP. The multi-proxy analysis suggests three climatic regimes throughout the Holocene inSouthern Patagonia: i) an early Holocene wet period (with the exception of two dry excursions at 10.5 ka and 8.5ka BP), ii) a mid-Holocene dry period and iii), a return to generally wet conditions over the late Holocene. Theglobal drivers for these tri-phased climatic regimes are likely related to oceanic and South polar feedbacks. Theearly Holocene was the warmest period and might be attributable to changes in global ocean circulation whichinvolved a rise in air T◦ and a strength in SWW from 50◦S, and therefore higher precipitations over landmass.After 9 ka BP, an intensified deglaciation dynamic along the Antarctic Peninsula is concordant with increasingsummer insolation in the Southern hemisphere, leading to a poleward shift of the SWWs in response to globalwarming and thus to a reduction in moisture supply from the Pacific onto the Patagonian shore. After 5 ka BP, agradual SST decline is consistent with an equatorward ...