Wang Rui, Liu Zhaofei, Jiang Liguang, Yao Zhijun, Wang Junbo, Ju Jianting
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
J Environ Sci (China). 2016 Mar;41:183-194. doi: 10.1016/j.jes.2015.03.016. Epub 2015 Jun 13.
The geochemistry of natural waters in the Changtang Nature Reserve, northern Tibet, can help us understand the geology of catchments, and provide additional insight in surface processes that influence water chemistry such as rock weathering on the Qinghai-Tibet Plateau. However, severe natural conditions are responsible for a lack of scientific data for this area. This study represents the first investigation of the chemical composition of surface waters and weathering effects in two lake basins in the reserve (Lake Dogaicoring Qiangco and Lake Longwei Co). The results indicate that total dissolved solids (TDS) in the two lakes are significantly higher than in other gauged lakes on the Qinghai-Tibet Plateau, reaching 20-40g/L, and that TDS of the tectonic lake (Lake Dogaicoring Qiangco) is significantly higher than that of the barrier lake (Lake Longwei Co). Na(+) and Cl(-) are the dominant ions in the lake waters as well as in the glacier-fed lake inflows, with chemical compositions mainly affected by halite weathering. In contrast, ion contents of inflowing rivers fed by nearby runoff are lower and concentrations of dominant ions are not significant. Evaporite, silicate, and carbonate weathering has relatively equal effects on these rivers. Due to their limited scope, small streams near the lakes are less affected by carbonate than by silicate weathering.
西藏北部羌塘自然保护区天然水体的地球化学特征有助于我们了解集水区的地质情况，并为影响水化学的地表过程（如青藏高原的岩石风化）提供更多见解。然而，恶劣的自然条件导致该地区缺乏科学数据。本研究首次对该保护区两个湖盆（多格错仁强错湖和龙尾错湖）地表水的化学成分及风化作用进行了调查。结果表明，这两个湖泊的总溶解固体（TDS）显著高于青藏高原其他已测量的湖泊，达到20 - 40克/升，且构造湖（多格错仁强错湖）的TDS显著高于堰塞湖（龙尾错湖）。Na(+)和Cl(-)是湖水以及冰川补给的入湖水流中的主要离子，其化学成分主要受石盐风化影响。相比之下，由附近径流补给的入流河水离子含量较低，主要离子浓度不显著。蒸发岩、硅酸盐和碳酸盐风化对这些河流的影响相对相当。由于范围有限，湖泊附近的小溪受碳酸盐风化的影响小于硅酸盐风化。
