The 9.2 ka event in Asian summer monsoon area: the strongestmillennial scale collapse of the monsoon during the Holocene

Numerous Holocene paleo-proxy records exhibit a series of centennial-millennial scale rapid climatic events. Unlike the widely acknowledged 8.2ka climate anomaly, the likelihood of a significant climate excursion at around 9.2cal ka BP, which has been notably recognized in some studies, remains to b...

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Bibliographic Details
Published in:Climate Dynamics
Main Authors: Zhang,WC(Zhang,Wenchao), Yan,H(Yan,Hong), Dodson,J(Dodson,John), Cheng,P(Cheng,Peng), Liu,CC(Liu,Chengcheng), Li,YJ(Li,Jianyong), Lu,FY(Lu,Fengyan), Zhou,WJ(Zhou,Weijian), An,ZS(An,Zhisheng), Yan,Hong
Format: Report
Language:English
Published: 2017
Subjects:
Dajiuhu Peat
Central China
Paleoclimaterecords
Abrupt Climate Changes
9.2 Ka Bp Event
Weakasian Summer Monsoon
Greenland
North Atlantic
Online Access:http://ir.ieecas.cn/handle/361006/5635
https://doi.org/10.1007/s00382-017-3770-2
Description
Summary:Numerous Holocene paleo-proxy records exhibit a series of centennial-millennial scale rapid climatic events. Unlike the widely acknowledged 8.2ka climate anomaly, the likelihood of a significant climate excursion at around 9.2cal ka BP, which has been notably recognized in some studies, remains to be fully clarified in terms of its magnitude and intensity, as well as its characteristics and spatial distributions in a range of paleoclimatic records. In this study, a peat sediment profile from the Dajiuhu Basin in central China was collected with several geochemical proxies and a pollen analysis carried out to help improve understanding of the climate changes around 9.2cal ka BP. The results show that the peat development was interrupted abruptly at around 9.2cal ka BP, when the chemical weathering strength decreased and the tree-pollen declined. This suggests that a strong drier regional climatic event occurred at around 9.2cal ka BP in central China, which was, in turn, probably connected to the rapid 9.2ka climate event co-developing worldwide. In addition, based on the synthesis of our peat records and the other Holocene hydrological records from Asian summer monsoon (ASM) region, we further found that the 9.2ka event probably constituted the strongest abrupt collapse of the Asian monsoon system during the full Holocene interval. The correlations between ASM and the atmospheric 14C production rate, the North Atlantic drift ice records and Greenland temperature indicated that the weakened ASM event at around 9.2cal ka BP could be interpreted by the co-influence of external and internal factors, related to the changes of the solar activity and the Atlantic Meridional Overturning Circulation (AMOC).

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