中文摘要：

对藏南普莫雍错湖水及其周围入湖河流水体进行了离子化学成分分析，对部分湖泊和河流水样作氧同位素分析．结果显示，不同入湖河流离子组成与湖水本身离子组成有较大差异．湖水的主要离子组合是Mg^2＋-Ca^2＋-HCO3^-SO4^20，而主要补给河流加曲为Ca^2＋-MgO^2＋-HCO3^-．加曲入湖河口2m水深以内水化学性质差异大，湖泊其他地区差异小．加曲对河口三角洲之上湖水影响显著．其他河流对河口处湖水影响较小．Gibbs图显示湖水离子的组成主要与流域内的岩石风化有关．离子比例和三角图分析说明控制入湖河水离子主要过程是碳酸盐、黄铁矿和硅酸盐风化．湖泊与河流水体离子的组成差异较大，原因可能是蒸发浓缩导致的CaCO3的沉淀．其结果有助于正确理解湖泊沉积碳酸盐的环境指示意义．

英文摘要：

The chemistry of major cations （Mg^2＋, Ca^2＋, Na^＋ and K^＋） and anions （HCO3^-, SO4^2- and Cl^-） in the water of Lake Pumayum Co and of its inflow river were studied, and the results revealed the obvious ionic difference among various inflow rivers and the lake. The chemical type of the lake water was Mg^2＋-Ca^2＋-HCO3^--SO4^2-, and the major ions of the main inflow river were Ca^2＋ -Mg^2＋-HCO3^-. In the lake inlet within the depth less than 2m of Jiaqu River, the main inflow river, there was significant variance of water chemistry. However, it was almost same at other area of the lake. Jiaqu River had a distinct effect on the chemistry of the water on the estuary delta, whereas other rivers have minor effect on the water on estuary. The Gibbs plot revealed that chemical compositions of the lake water was correlative with rock weathering in the drainage area. Ion ratio and ternary plots further explored the main processes controlling the water chemistry of the catchment were carbonate weathering, pyrite weathering and silicate weathering. The different water chemical characteristics between fiver water and lake water may result from the CaCO3 precipitation. The outcome will benefit comprehending the environmental significance of carbonate in lacustrine sediment.