藏南羊卓雍错流域水化学区域差异及其成因

Spatial variation and its causes of water chemical property in Yamzhog Yumco Basin, South Tibet

特殊的地理环境造成青藏高原高寒区水化学性质及其动态的特殊性。本文通过对藏南羊卓雍错流域进行水样采集、分析与测定,探讨了该流域水化学性质的区域差异及其成因。结果表明,羊卓雍错流域水化学性质区域差异明显主要是自然因素综合作用的结果,而人类活动对区域水化学性质亦有所贡献。首先,在特殊的高寒气候条件下,流域内各湖泊水化学性质差异的根本原因是其水文条件不同。其次,羊卓雍错西南部湖水样品中硼和锂含量偏高说明该区域湖相沉积中可能存在硼酸盐矿物和含锂菱镁矿。第三,流域东部和西部河水化学性质差异明显的主因是河流所经地区地质条件不同;羊卓雍错南岸和北岸地下水化学性质差异的关键则是区域水系发育程度不同。此外,巴纠错、嘎马林河和羊卓雍错南岸水井样品的总氮含量较高,这反映了人类活动对区域水化学性质的影响。

Due to the special geographical environment, the water chemical property and its spatial-temporal change over the Qinghai-Tibetan Plateau is significant to clarify the chemical characteristics of natural water. Hence, a large number of water samples were collected and their chemical parameters were measured from major lakes, rivers and wells in the Yamzhog Yumco Basin, South Tibet. And then the spatial variation of water chemical property and its possible causes were analyzed. The results revealed that the spatial variation of water chemical property was obvious, which might be attributed to the major influence of natural processes and minor impact of human activities. And the detailed results suggested that （1） owing to the outflows existing for Kongmu Co and Puma Yumco, the values of chemical parameters in the two lakes were much lower than those in the other three enclosed lakes （i. e., Yamzhog Yumco, Bajiu Co and Chen Co）, （2） the high boron （B） and lithium （Li） concentrations indicated that there might be some boron minerals and magnesites in the southwestern part of the Yamzhog Yumco lake basin, （3） it is the disparate geologic conditions that cause the river water chemical property significantly different from the western and eastern parts which the river flows through, and （4） the drainage distribution could account for the significant differences of the well water chemical property between the southern and northern lake banks of the Yamzhog Yumco.