矿床地球化学国家重点实验室知识库

This study presents chlorine isotopic composition of salt deposits recovered in a core from the Qarhan Saline Lake in the Qinghai Province of China. The delta Cl-37 trend has three stages, and they correspond to the upper, middle, and lower salt-bearing groups of the entire evaporite system. The delta Cl-37 values are between -0.22 parts per thousand and 0.13 parts per thousand with an average value of -0.02 parts per thousand in the lower salt-bearing group. It ranges between 0.14 parts per thousand and 0.76 parts per thousand ((x) over bar=-0.36 parts per thousand) in the middle salt-bearing group, and varies between -0.35 parts per thousand to 0.35 parts per thousand ((x) over bar = -0.04 parts per thousand) in the upper salt-bearing group. This work indicates that stratification of delta Cl-37 values is accompanied by stratigraphic variations in Mg/Cl and K/Cl in halite. We suggest a "evaporation cycles model" and it indicates the potential of Cl isotope as a geochemical tracer in order to understand paleoclimatic conditions during different stages of evaporite deposition.