LI Linglong, LIU Zaihua

(State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002)

Abstract: In recent years, monitoring drip water-CaCO3 systems in karst caves to understand the forcing mechanisms of modern calcite has become the focus in speleothem paleoenvironmental research. Especially, the study on oxygen isotope compositions has achieved considerable progress. In the study on the relationship between CaCO3 δ18O and temperature, researchers modified the commonly used equations continuously, and even put forward their own equations which are more appropriate to their research areas, and thus increased the accuracy and confidence level of the calculated paleotemperature. In the study on carbon isotopes, researchers studied various influences on the δ13C values in more detail (such as PCP, Ventilation), which provide a scientific support to reconstructing the paleoclimate with the speleothem δ13C values. However, due to complex drip water-CaCO3 systems, the integrated monitoring systems haven’t set up in most cases. Therefore, there is high uncertainty in climatic interpretation of carbon and oxygen isotopic compositions need to be solved in future researches.

Key words: Cave drip water-CaCO3 system; carbon; oxygen; isotopic composition; prior calcite precipitation; equilibrium fractionation; dynamic fractionation; speleothem paleoclimate reconstruction

EARTH AND ENVIRONMENT Vol. 43, No.2, Tot No.304, 2015, Page 223-232