HR: 0800h
AN: PP31A-1515    [Abstracts]
TI: Cosmogenic Be-10 Dating of Moraine in Tianshan, Central Asia
AU: * Kong, P
EM: pingkong@mail.igcas.ac.cn
AF: Institute of Geology and Geophysics, CAS, P.O. Box 9825, Beijing, 100029 China
AU: * Kong, P
EM: pingkong@mail.igcas.ac.cn
AF: Institute of Tibetan Plateau Research, CAS, P.O. Box 9825, Beijing, 100029 China
AU: Na, C
EM: cg_na@mail.igcas.ac.cn
AF: Institute of Geology and Geophysics, CAS, P.O. Box 9825, Beijing, 100029 China
AU: Fink, D
EM: fink@ansto.gov.au
AF: ANSTO-Environment, Australian Nuclear Science & Technology Organisation, Menai, NSW 2234 Australia
AU: Huang, F
EM: huangfeixin@mail.igcas.ac.cn
AF: Institute of Tibetan Plateau Research, CAS, P.O. Box 9825, Beijing, 100029 China
AB: The Tianshan mountain area is located towards the center of the Eurasian continent and is one of the driest regions in the world. Studies of glacial history in this region is especially important because it is far from the climatic key area of the North Atlantic, thus could better manifest interlink between ocean, atmosphere and terrestrial systems. Relating glacial advances in the extreme-continental environment to abrupt climatic changes initiated in the North Atlantic area which cannot be attributed directly to orbital forcing may especially improve the fundamental understanding of the interrelations of distinct elements of the earth climate system as well as the mechanisms underlying abrupt climate changes. Successions of well-preserved moraines are present in the Urumqi river head valley, Tianshan mountains. These moraines are relics of glacier advances and retreats during the late Quaternary. By using Be-10 surface-exposure dating of moraine boulders, we determined the timing of glacial advances in this area: ~17.7 ka, ~12.4 ka and ~8.3 ka. The first age is coincident with deglaciation after the Last Glacial Maximum (LGM) and the last two glacial advances are most likely associated with abrupt climate events after the LGM: the Younger Dryas and the 8200-year cooling event. Our results suggest a relation of glaciations in the Tianshan mountains with climate changes in the North Atlantic. The occurrence of glacial advances during abrupt climate cooling periods in the remote Eurasian continent suggests rapid linkages between ocean, atmosphere and terrestrial systems.
DE: 1150 Cosmogenic-nuclide exposure dating (4918)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4914 Continental climate records
DE: 4926 Glacial
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005