1. Century-scale climatic oscillations during the Last Glacial Maximum revealed by stalagmite isotopic records from Longfugong Cave, China.
- Author
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Zhang, Zhenqiu, Wang, Yongjin, Yang, Zhou, Liang, Yijia, Yang, Shaohua, Shao, Qingfeng, Zhang, Weihong, and Huang, Wei
- Subjects
LAST Glacial Maximum ,STALACTITES & stalagmites ,SPELEOTHEMS ,GROUND cover plants ,CAVES ,WESTERLIES - Abstract
The isotopic records of two
230 Th-dated stalagmites from Longfugong Cave, Mt. Shennongjia, central China, reveal a highly resolved Asian summer monsoon (ASM) history from 29.5 to 14.5 ka BP. The two δ18 O records are consistent with other Chinese cave δ18 O records, suggesting that our new records are of regional significance. Due to the reservoir mixing of seepage water in the epikarst system, the stalagmite δ18 O signals in this cave are more severely muted than those in other caves. Here, we observed that the amplitude of the δ13 C variability is approximately twice that of the δ18 O signal and can be used as a sensitive proxy of East Asian monsoon climates. First, the two stalagmite δ13 C records are consistent with each other on decadal to centennial timescales. Second, there are high correlation coefficients between the δ13 C and δ18 O signals over shorter timescales. Third, from 25.2 to 19.6 ka BP, six peaks in the δ13 C records were identified and are coincident with corresponding warming events in the Greenland ice-core δ18 O records, suggesting that strong coupling occurred between the high- and low-latitude northern climates on centennial timescales. Therefore, we propose that atmospheric transmission mechanisms probably played an important role in linking the ASM and Greenland climates on short timescales. A shift in westerly winds associated with variability in the extent of temperature in the North Atlantic likely influenced changes in hydrological and thermal conditions at the cave site, leading to changes in vegetation cover and soil CO2 concentrations above the cave. Therefore, the calcite δ13 C records probably had faster and more sensitive responses to rapid climate shifts compared with their related δ18 O records. [ABSTRACT FROM AUTHOR]- Published
- 2020
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