Climatic reconstruction of the last 200ka from the isotopic study of South France speleothems

• Main Author: Wainer, Karine
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), 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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Paris Sud - Paris XI, Dominique Genty([e-mail])
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2009
• Subjects: spéléothèmes; inclusions fluides; datations U-Th; delta47; Dernier Interglaciaire; cycle de Dansgaard-Oeschger; MIS 6; MIS 3; MIS 5; Terminaison II; d18Oc; d13Cc; luminescence; éléments en traces; paléotempérature; speleothems; fluid inclusions; last interglacial; Dansgaard-Oeshger cycle; traces éléments; paleotemperature; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; North Atlantic; permafrost
• Online Access: https://theses.hal.science/tel-00547900; https://theses.hal.science/tel-00547900/document; https://theses.hal.science/tel-00547900/file/Wainer_2009_These.pdf

This work aims to characterise the climatic variations of the last 200 ka through the study of four South France speleothems dated by the U-Th method. Between 175 and 165ka, the high resolution of the Villars Cave flowstone core (Vil-car-1) base record yields for the first time in the region, millennial climatic events. During Termination II, the isotopic composition of the same record shows a spectacular drop of the 18Oc of -5 ‰. The confrontation of these data with fluid inclusions 18Odw and calcite 47 suggests that (1) if isotopic equilibrium was satisfied, the Termination II warming is around 20°C, (3) if we consider that kinetic effect occurred, the warming amplitude should be about 14°C (corrected from kinetic effects). A stalagmite from a neighbour site didn't record such an amplitude of variation during Termination II: it reminds us the strong influence of the cave karstic system on speleothems isotopic signals. According to the study of 3 speleothems, the MIS5 was globally a warm and humid period with an alternation of warmer and more humid episodes and colder and drier ones. The latters are synchronous with cooling events in the North Atlantic Ocean. For MIS3, this study allows us to give precise ages to the Dansgaard-Oeschger (DO) cycles 14 end and 13 and 12 limits, thanks to a high resolution precisely dated by MCICPMS record. The end of the identified DO is synchronous to an abrupt cooling (short permafrost settlement). The growth cessation of this sample synchronous to the two others stalagmites growth cessation confirms an important cooling during MIS3 at 30ka. Le but de cette thèse est de caractériser les variations climatiques des derniers 200 ka à travers l'étude de quatre spéléothèmes du sud de la France, datés par U-Th. Nous nous sommes focalisés sur l'étude des stades isotopiques marins MIS 6, 5 et 3. Les principaux résultats obtenus sont les suivants : - mise en évidence d'oscillations milléniales au MIS6 entre 175 et 165 ka. L'enregistrement isotopique haute résolution (10 à 300 ans) ...