Century-scale climatic oscillations during the Last Glacial Maximum revealed by stalagmite isotopic records from Longfugong Cave, China

• Published in: Environmental earth sciences 2020-12, Vol.79 (23), Article 517
• Main Authors: Zhang, Zhenqiu, Wang, Yongjin, Yang, Zhou, Liang, Yijia, Yang, Shaohua, Shao, Qingfeng, Zhang, Weihong, Huang, Wei
• Format: Article
• Language: English
• Subjects: Archives & records; Atmospheric transmission; Biogeosciences; Calcite; Carbon dioxide; Carbon dioxide concentration; Caves; Climate; Climatic cycles; Coefficients; Correlation coefficient; Correlation coefficients; Earth and Environmental Science; Earth science; Earth Sciences; East Asian monsoon; Environmental Science and Engineering; Geochemistry; Geography; Geology; Hydrology; Hydrology/Water Resources; Ice cores; Last Glacial Maximum; Monsoon climates; Monsoons; New records; Original Article; Oscillations; Plant cover; Precipitation; Seepage; Soil; Summer monsoon; Terrestrial Pollution; Variability; Vegetation; Vegetation cover; Ventilation; Water seepage; Wind; Winds
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-020-09250-6

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 δ 18 O records are consistent with other Chinese cave δ 18 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 δ 18 O signals in this cave are more severely muted than those in other caves. Here, we observed that the amplitude of the δ 13 C variability is approximately twice that of the δ 18 O signal and can be used as a sensitive proxy of East Asian monsoon climates. First, the two stalagmite δ 13 C records are consistent with each other on decadal to centennial timescales. Second, there are high correlation coefficients between the δ 13 C and δ 18 O signals over shorter timescales. Third, from 25.2 to 19.6 ka BP, six peaks in the δ 13 C records were identified and are coincident with corresponding warming events in the Greenland ice-core δ 18 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 CO 2 concentrations above the cave. Therefore, the calcite δ 13 C records probably had faster and more sensitive responses to rapid climate shifts compared with their related δ 18 O records.