Noble Gases from Fluid Inclusions of Stalagmite and Their Contribution to Reconstruct the Variability of Paleotemperature in the Middle Reaches of the Yangtze River, China

A new method to estimate paleotemperature change is reported in this article. The authors successfully exploit the Xe/Ar ratio trapped in the fluid inclusion of stalagmites for reconstructing climatic evolution since the Last Glacial Maximum (LGM), in the middle reaches of the Yangtze River, where the East Asian monsoon prevails. A logarithmic expression namely ln(CXe/CAr) proves to be bound up with warm/cold cycles. The δ13C and Mg/Ca curves drawn from the investigated stalagmites mostly follow the fluctuation of regional paleotemperature, but may be overprinted by other climatic signals. This study clearly states that among the diverse proxies, the Xe/Ar ratio recorded in the fluid inclusion is probably the best indicator, constantly mirroring the temperature variation. The ln(CXe/CAr) profile on the whole shows an identification with those curves oscillating essentially between the warm and cold phases. After integrating the noble gas profile with the δ13C and Mg/Ca signals, the authors underline eight warm/cold cyclothems developed in the region under study since LGM. The pattern of the climate variation displayed by the integration is reasonable for interpreting the regional environment evolution during the last 20,000 years.