Based on 33 U/Th dates and 1020 oxygen isotopic data from stalagmite Y1 from Yamen Cave, Guizhou Province, China, a record of the Asian Summer Monsoon (ASM) was established. The record covers the last deglaciation and the early Holocene (from 16. 2 to 7. 3 ka BP) with an average oxygen isotope resolution of 9 years. The main millennial-scale deglacial events first identified in Greenland (Greenland Interstadial Events: GIS 1e through GIS 1a) and later in China are clearly present in the Y1 record. By analogy to earlier work, we refer to these as Chinese Interstadials (CIS): CIS A. 1e to CIS A. 1a. The onset of these events in Y1 δ18O records are nominally dated at: 14750±50, 14100±60, 13870±80, 13370±80, and 12990±80 a BP. The end of CIS A. 1a or the beginning of the Younger Dryas (YD) event is nominally at 12850±50 a BP and the end of the YD dates to 11500±40 a BP. The δ18O values shift by close to 3‰ during the transition into the Bølling-Allerød (BA, the onset of CIS A. 1e) and at the end of the YD. Comparisons of Y1 to previously published early Holocene records show no significant phase differences. Thus, the East Asia Monsoon and the Indian Monsoon do not appear to have been out of phase during this interval. The Y1 record confirms earlier work that suggested that solar insolation and North Atlantic climate both affect the Asian Monsoon.
Bibliographical noteFunding Information:
We thank Dr. X. F. Wang and Ms. C. A. Dykoski at the Department of Geology and Geophysics, University of Minnesota, USA, for their great help in U/Th dating work. Thanks to Academician An Zhisheng, Prof. Liu Weiguo, Prof. Wen Qibin, and Dr. Li Xiangzhong at the State Key Laboratory of Loess and Quaternary Geology, Chinese Academy of Sciences for assistance in the stable isotope analysis. Thanks to Ran Jingcheng and Chen Huiming et al. in the National Maolan Conservation Region, for their great help in field work. We thank Prof. Li Hongchun, Dr. Li Tingyong, Dr. Yang Xunlin and Dr. Liu Ziqi in the Laboratory of Geochemistry and Isotope, Southwest University, China, for assistance in the isotope analysis and useful discussion. We also thank the helpful suggestions from two anonymous reviewers. This work was supported by National Natural Science Foundation of China (Grant Nos. 40231008, 40902053, 90511004, 40672165, 40772216), US National Science Foundation (Grant No. 052535), Science Foundation of Southwest University (Grant No. SWUB-2008047), Foundation of Karst Dynamics Laboratory, MLR (Grant No. 2006-05), National Key Program of Science and Technology (Grant No. 2006BAC01A16), Natural Science Foundation Project of Chongqing (Grant No. CSTC, 2009BA0002) and Geological Survey Project of MLR (Grant No. 1212010634805).
- Asian Monsoon
- The last deglaciation
- U-series dating
- Yamen Cave