Geological Society of America

T102 Lacustrine Systems across Space and Time I

Monday, 23 October 2017
8:00 AM - 12:00 PM
Room 307/308

THE OSCILLATING FRINGE OF THE EAST ASIAN MONSOON

Paper number: T102-16
Program: Technical Sessions
Time: 11:45 AM – 12:00 PM

Authors

Yonaton Goldsmith Presenting Author
Caltech, Pasadena, CA
Hai Xu
Chinese Academy of Sciences, Xi'an
Pratigya J. Polissar
Lamont Doherty Earth Observatory, Palisades, NY
Wallace Broecker
New York, NY
Peter deMenocal
Columbia University, New York, NY
Jianghu Lan
Chinese Academy of Sciences, Xi'an
Peng Cheng
Institute of Earth Environment,Chinese Academy of Sciences, Xi'an
Weijian Zhou
Institute of Earth Environment, Chinese Academy of Sciences, Xi'an
Zhisheng An
Xi'an

Abstract

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. δD_wax 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 δ_p are associated with real rainfall changes.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-304574

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