HR: 10:20h
AN: PP32A-01    [Abstracts]
TI: Clear signature of Last Glacial Maximum advances in Southern Tibet
AU: * Chevalier, M
EM: mlc@stanford.edu
AF: Stanford University, Mitchell building GES 450 Serra Mall, Braun Hall, Stanford, ca 94305, United States
AU: * Chevalier, M
EM: mlc@stanford.edu
AF: Institut de Physique du Globe de Paris, Laboratoire de Tectonique, case 89 4 place Jussieu, paris, 75005, France
AU: Ryerson, F J
EM: ryerson1@llnl.gov
AF: Lawrence Livermore National Laboratory, IGPP, 7000 East Avenue, Livermore, ca 94550, United States
AU: Van Der Woerd, J
EM: Jerome.Vanderwoerd@eost.u-strasbg.fr
AF: Institut de Physique du Globe de Strasbourg, 5, rue Rene Descartes, Strasbourg, 67084, France
AU: Tapponnier, P
EM: tappon@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, Laboratoire de Tectonique, case 89 4 place Jussieu, paris, 75005, France
AU: Finkel, R C
EM: finkel1@llnl.gov
AF: Lawrence Livermore National Laboratory, IGPP, 7000 East Avenue, Livermore, ca 94550, United States
AU: Li, H
EM: lihaibing@ccsd.org.cn
AF: Institute of Geology, CAGS, 26, Baiwanzhuang Road, Beijing, 100037, China
AB: The extent and timing of glacial fluctuations during the Late Quaternary provide essential information on past climatic changes, which in turn enhance our ability to predict future climate change. Controversy exists with regard to the glacial history of the Himalayas and Tibet, particularly on the geologic signature, timing and magnitude of the Last Glacial Maximum (LGM) relative to previous advances. Indeed, Quaternary glaciations in Tibet and the Himalayas, and in other parts of the Northern Hemisphere may have been asynchronous. Here, based on cosmogenic radionuclide (CRN) dating of 7 glacial features (68 samples), we demonstrate a clear signature of an LGM glacial advance in Southern and Western Tibet, but also that the largest glaciation (in terms of preserved deposits) took place ~40 ka ago (Marine Isotope Stage MIS-3). Further, it appears that most of the global and local temperature minima in the various climate proxy curves (e.g. Marine oxygen Isotope Stages MIS, Specmap) were coeval with the prominent glacial advances found in Tibet. These data indicate that glacial advances in Tibet and elsewhere in the Northern Hemisphere are synchronous and modulated by global climate variability, but that their extent may vary due to local conditions.
DE: 1105 Quaternary geochronology
DE: 1150 Cosmogenic-nuclide exposure dating (4918)
DE: 1824 Geomorphology: general (1625)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 8177 Tectonics and climatic interactions
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting