柴达木盆地盐湖形成演化与水体来源关系的地球化学初步模拟:Pitzer模型的应用

Geochemical simulation of formation and evolution of salt lakes and their water sources in Qardam Basin: Application of Pitzer's model

利用Pitzer模型,对柴达木盆地盐湖、地表河水以及地表河水同深部来源的CaCl2水体以不同的比例混合后进一步演化的结晶路线进行了研究。结果表明,柴达木盆地硫酸镁亚型盐湖的结晶路线可分为四类,氯化物型盐湖的结晶路线可分为两类,他们的形成不可能是地表河水蒸发演化到一定阶段的产物。地表河水同深部来源CaCl2水体以不同比例混合掺杂后水体水化学类型及析盐途径各不相同,它们同盆地内不同盐湖的水化学类型及其析盐途径具有很好的对应关系,说明柴达木盆地盐湖的形成同盆地内存在的两种水体———地表河水和深部来源CaCl2水体有着密切的关系。

The evaporation sequence and path of salt lakes, surface river waters and waters, which are the mixture of surface river waters and CaCl2 water at different ratios originating from the deep are studied in Qardam Basin based on Pitzers model. The results indicate that there are four evaporation paths forMgSO4 sub type salt lakes and two evaporation paths for chloride type salt lakes. The formation of all salt lakes cannot be the products of evaporation of the surface river waters during the different stages. Although the hydrochemical type and evaporation path of the mixed waters are different, they have good correspondence with the hydrochemical type and evaporation path of different salt lakes in the basin. Therefore, the formation of salt lakes in the basin is closely related to the surface river waters and the CaCl2 water originating from the deep.