ABSTRACT

Shallow groundwater and lake water are the dominant water resources in the Badain Jaran Desert. There are still controversial hypotheses related to the origin of groundwater in this desert. Few studies have been conducted to explore the Sr provenance of these waters and assess the water–rock interactions using a Sr isotope approach until now. In this text, the Sr isotope data of waters in the hinterland of the Badain Jaran Desert and neighbouring areas are reported. The waters in the Badain Jaran Desert have few links to its surrounding rivers, but could be influenced by the precipitation in the Yabulai Mountains. The ⁸⁷Sr/⁸⁶Sr ratio changes constantly, while the Sr²⁺ concentration of shallow groundwater gradually decreases from Yabulai to the desert hinterland to Gurinai-Guaizihu. Combined with hydrochemical data and hydrodynamic conditions, these results show that the dissolved Sr of waters in the desert hinterland is controlled by the Yabulai precipitation and catchment weathering. They further show that the desert shallow groundwater Sr originates mainly from the Yabulai precipitation (> 94 %), while whole-rock weathering contributes little (< 6 %), as calculated using isotope mass balance equations. Relative Sr contributions to lakes from shallow groundwater and catchment weathering are calculated to be 92.5 and 7.5 %, respectively.

摘要

浅层地下水和湖水是巴丹吉林沙漠的主要水资源。关于这个沙漠中地下水的起源，仍然存在有争议的假设。迄今为止，很少有研究使用 Sr 同位素方法探索这些水域的 Sr 来源并评估水-岩相互作用。本文报道了巴丹吉林沙漠腹地及邻近地区水域的Sr同位素数据。巴丹吉林沙漠的水域与周围河流几乎没有联系，但可能受到亚布赖山脉降水的影响。在⁸⁷ SR / ⁸⁶ Sr比值不断的变化，而SR ²⁺浅层地下水浓度从亚布赖向沙漠腹地到古里奈-怪子湖逐渐降低。结合水化学数据和水动力条件，这些结果表明，沙漠腹地水域的溶解Sr受亚布赖降水和流域风化的控制。他们进一步表明，使用同位素质量平衡方程计算，沙漠浅层地下水 Sr 主要来源于亚布赖降水（> 94 %），而全岩风化贡献很小（< 6 %）。浅层地下水和集水区风化对湖泊的相对 Sr 贡献计算分别为 92.5% 和 7.5%。