Century-scale climatic oscillations during the Last Glacial Maximum revealed by stalagmite isotopic records from Longfug
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ORIGINAL ARTICLE
Century‑scale climatic oscillations during the Last Glacial Maximum revealed by stalagmite isotopic records from Longfugong Cave, China Zhenqiu Zhang1,2 · Yongjin Wang2 · Zhou Yang1 · Yijia Liang2 · Shaohua Yang2 · Qingfeng Shao2 · Weihong Zhang3 · Wei Huang4 Received: 7 November 2019 / Accepted: 14 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The isotopic records of two 230Th-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 δ18O records are consistent with other Chinese cave δ18O records, suggesting that our new records are of regional significance. Due to the reservoir mixing of seepage water in the epikarst system, the stalagmite δ18O signals in this cave are more severely muted than those in other caves. Here, we observed that the amplitude of the δ13C variability is approximately twice that of the δ18O signal and can be used as a sensitive proxy of East Asian monsoon climates. First, the two stalagmite δ13C records are consistent with each other on decadal to centennial timescales. Second, there are high correlation coefficients between the δ13C and δ18O signals over shorter timescales. Third, from 25.2 to 19.6 ka BP, six peaks in the δ13C records were identified and are coincident with corresponding warming events in the Greenland ice-core δ18O 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 δ13C records probably had faster and more sensitive responses to rapid climate shifts compared with their related δ18O records. Keywords Last glacial maximum · Chinese stalagmite · Carbon isotope · Asian summer monsoon
Introduction Marine Oxygen Isotope Stage (MIS) 2 (29–14 ka BP, Lisiecki and Raymo (2005)), which covered the Last Glacial Maximum (LGM) (from 26.5 to 19–20 ka BP in the Northern Hemisphere, Clark et al. (2009)) and Termination I, is a crucial period for understanding how the Asian summer * Yongjin Wang [email protected] 1
School of Life Science, Nanjing Normal University, Nanjing 210023, China
2
College of Geography Science, Nanjing Normal University, Nanjing 210023, China
3
College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
4
Department of Geographical Science, Yichun University, Yichun 336000, China
monsoon (ASM) and its subsystems respond to global climate change. Various factors, such as insolation, ice volume, and atmospheric and oceanic
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