Northward extent of East Asian monsoon covaries with intensity on orbital and millennial timescales.
The magnitude, rate, and extent of past and future East Asian monsoon (EAM) rainfall fluctuations remain unresolved. Here, late Pleistocene-Holocene EAM rainfall intensity is reconstructed using a well-dated northeastern China closed-basin lake area record located at the modern northwestern fringe of the EAM. The EAM intensity and northern extent alternated rapidly between wet and dry periods on time scales of centuries. Lake levels were 60 m higher than present during the early and middle Holocene, requiring a twofold increase in annual rainfall, which, based on modern rainfall distribution, requires a ∼400 km northward expansion/migration of the EAM. The lake record is highly correlated with both northern and southern Chinese cave deposit isotope records, supporting rainfall "intensity based" interpretations of these deposits as opposed to an alternative "water vapor sourcing" interpretation. These results indicate that EAM intensity and the northward extent covary on orbital and millennial timescales. The termination of wet conditions at 5.5 ka BP (∼35 m lake drop) triggered a large cultural collapse of Early Neolithic cultures in north China, and possibly promoted the emergence of complex societies of the Late Neolithic.
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964; yonig@ldeo.columbia.edu xuhai@ieecas.cn.
Yonaton
Y
Goldsmith
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964.
Wallace S
WS
Broecker
State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi, China; yonig@ldeo.columbia.edu xuhai@ieecas.cn.
Hai
H
Xu
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964.
Pratigya J
PJ
Polissar
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964.
Peter B
PB
deMenocal
Geological Survey of Israel, Jerusalem 95501, Israel.
Naomi
N
Porat
State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi, China.
Jianghu
J
Lan
State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi, China.
Peng
P
Cheng
State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi, China.
Weijian
W
Zhou
State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi, China.
Zhisheng
Z
An
Chinese cave record; East Asian monsoon; closed-basin lake; northward expansion; paleo-rainfall