Characterization of the Asian Monsoon during Marine Isotope Stages 8 and 9 from Stalagmite Calcite Collected from Dongge Cave, China

HR: 08:00h
AN: PP11C-01 [Abstracts]
TI: Characterization of the Asian Monsoon during Marine Isotope Stages 8 and 9 from Stalagmite Calcite Collected from Dongge Cave, China
AU: * Dykoski, C A
EM: dyko0008@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455 United States
AU: Edwards, R L
EM:
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455 United States
AU: Cheng, H
EM:
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455 United States
AU: Yuan, D
EM:
AF: Karst Dynamic Laboratory, The Ministry of Land Resources, Guilin, 541004 China
AU: Wang, Y
EM:
AF: College of Geography Science, Nanjing Normal University, Nanjing, 210097 China
AB: Previous work from several stalagmites collected from Dongge Cave, China has shown significant shifts in oxygen isotope values, which have been interpreted in terms of changes in Asian monsoon strength (Wang et al. 2005, Science, 308, 854-857; Dykoski et al. 2005, EPSL, 233, 71-86; Yuan et al. 2004, Science, 304, 575-578;). Using other climate records from around the world, correlations have been made to determine the driving mechanisms of atmospheric circulation and how circulation patterns change over glacial/interglacial (G/I) cycles. A nearly continuous record of the Asian monsoon has been obtained over the most recent 250 thousand years (kyr) covering two G/I cycles. Here, we present the extension of the monsoon record back as far as 330 kyr to determine how monsoon behavior has changed, if at all, with respect to other factors that affect climate such as insolation, atmospheric gas composition, continental ice volume, and sea level. The oxygen isotope data from stalagmite D10 record significant variations from 250 kyr to 330 kyr. Preliminary data show multiple large shifts in δ¹⁸O of up to 4 per mil with values ranging from ~-9 to -5 per mil. Changes in monsoon strength are consistent within error with insolation forcing at Marine Isotope Stages (MIS) 9.3, 9.1, and 8.5. Using high-resolution data in combination with ²³^OTh ages, we identify the oldest of these shifts as the transition between MIS 9.3 and 9.2. The observed range of values is consistent with the range of δ¹⁸O values observed during later Asian monsoon G/I transitions, such as the Last Interglacial 5e/5d transition. Future high-resolution work aims to determine the exact nature of Asian monsoon variation throughout the MIS 9/8 transition and MIS 8.
DE: 1000 GEOCHEMISTRY
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3344 Paleoclimatology (0473, 4900)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005