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    TIMS U-Th dating and high-resolution oxygen isotopic composition measurements were conducted on a stalagmite SI3 collected from Shizi cave, Nuoshuihe, northeastern Sichuan, Central China. The stalagmite SI3 was developed between 54-46 ka. Its δ18O record displays a high similarity with those of stalagmites MSL and MSD from Hulu cave, East China and D4 from Dongge cave, Southwest China, respectively. The trend of the δ18O record of SI3 also parallels with those of ice core GISP2 from polar area and of speleothem in Israel. These suggest that the δ18O record of SI3 is closely related with summer monsoon variation in East Asia. However, some evidences seem to suggest that carbonates in SI3 are more 18O enriched than those deposited under oxygen isotopic equilibrium condition. There was probably kinetic fractionation when SI3 was developed. This may be explained by the locus of SI3 that was collected near the entrance of Shizi cave. The possible mechanism between the δ18O record of SI3 and the variation in East Asian summer monsoon was speculated. It is suggested that in the East Asian summer monsoon domain, the δ18O record of some speleothem deposited even under nonequilibrium condition is still a potential proxy for summer monsoon variation.
    Stalagmite
    Speleothem
    δ18O
    East Asian Monsoon
    Ice core
    Citations (0)
    Stable oxygen and carbon isotope ratios (δ13C and δ18O) are the most applied climate and environmental proxies in speleothems allowing to infer past changes in cave drip water δ13C and δ18O related to climate and environmental variations from above the cave. However, disequilibrium isotope fractionation processes can modify δ13C and δ18O values in speleothems, which is in most cases difficult to estimate due to inter-dependencies on various cave specific parameter. To better understand the effect of these disequilibrium isotope fractionation processes proxy system models were developed in recent years, such as the ISOLUTION model. Here the code of the ISOLUTION model is made available for the public and the speleothem community to be applied to research questions that arise from e.g. monitoring programs that investigate δ13C and δ18O values of in situ calcite precipitates on watch glasses or modern speleothem calcite, respectively. Another application of the ISOLUTION model is to investigate the dependence of calcite δ13C and δ18O on the variation of one or multiple cave specific parameter, such as cave air temperature, drip interval, cave air pCO2, Ca2+ concentration of the drip water as well as on relative humidity and wind velocity. This allows to quantitatively estimate the effect of disequilibrium isotope fractionation processes in individual caves and drip sites on speleothem δ13C and δ18O values for modern and past climates and may help to further elucidate the complex interplay of kinetic and disequilibrium isotope fractionation.
    Speleothem
    δ18O
    Disequilibrium
    Stalagmite
    Equilibrium fractionation
    Citations (22)