Paper No. 102-14
Presentation Time: 11:45 AM
THE OSCILLATING FRINGE OF THE EAST ASIAN MONSOON
GOLDSMITH, Yonaton1, XU, Hai2, POLISSAR, Pratigya J.3, BROECKER, Wallace4, DEMENOCAL, Peter5, LAN, Jianghu2, CHENG, Peng6, ZHOU, Weijian7 and AN, Zhisheng8, (1)Division of Geological and Planetary Sciences, Caltech, Pasadena, CA 91125, (2)Division of Geological and Planetary Sciences State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China, (3)Biology and Paleoenvironment, Lamont Doherty Earth Observatory, 61 Route 9W, PO Box 1000, Palisades, NY 10964-8000, (4)Columbia University, Lamont-Doherty Earth Observatory, New York, NY 10027, (5)Earth and Environmental Sciences, Columbia University, New York, NY 10025, (6)State Key Lab of Loess and Quaternary Geology, Institute of Earth Environment,Chinese Academy of Sciences, No.97 Yanxiang Road, Yanta Zone, Xi'an, 710061, China, (7)State Key Lab of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, No.97 Yanxiang Road, Yanta Zone, Xi'an, 710061, China, (8)State Key Lab of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710075, China, yonig@caltech
The magnitude, rate and extent of East Asian Monsoon (EAM) rainfall changes during the late Pleistocene-Holocene are reconstructed using the first well-dated northeastern China lake-area record from a closed-lake basin, which enables reconstructing quantitative paleo-rainfall amounts. In addition, compound specific hydrogen isotopes (δD
wax) from lake-sediments are used to reconstruct the isotopic composition of rainwater (δ
P).
Lake-levels were 60 m higher than present during the early and middle Holocene. A mean annual rainfall increase of at least two times higher than today and a ~400 km northward expansion is required to sustain the high stand lake levels. Rainfall amount and the northern extent of the EAM alternated abruptly between wet and dry periods on time scales of a few centuries. Both the onset (~60 m rise at 11.5 ka BP) and termination (~35 m drop at 5.5 ka BP) of the Holocene humid period occurred abruptly, within centuries. δDwax from samples where both age and lake level are well constrained (n=5) show a significant correlation with lake level. In addition, lake level is correlated with both North and South Chinese stalagmite records, indicating that in North China changes in δp are associated with real rainfall changes.
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