Palaeohydrochemical and palaeohydrological changes of lakes have seldom been reconstructed from the fossil shells of the gasropod Radix auricularia, which is a new, and potentially high-resolution environnmental archive. We conducted a geochemical and stable isotope study of the shells of Radix from the exposed fluvio-lacustrine sediments near Lake Yamdrok Yumtso in the southern Tibetan Plateau. Our aims were to determine the sedimentary environment, palaeo-lake hydrochemistry and hydrological status. AMS 14C and OSL dating indicates that a lake-level stage of Yamdrok Yumtso higher than that of today occurred during ~4.7–1.2 cal. kyr BP. Results of Sr/Ca, δ13C and δ18O analysis of the fossil shells of Radix auricularia indicate that the lake-level fluctuations were mainly controlled by changes of the Indian Summer Monsoon; decreasing evaporation during the mid- to late-Holocene was also responsible. In addition, based on the geochemical relationship between Radix sp. shells and the ambient water in lakes, the values of δ18OPalaeo-water and Sr/CaPalaeo-water reconstructed using the fossil shells of Radix auricularia are −8.2‰ to −5.1‰ and 0.0012 to 0.0057, respectively. Further, based on the values of δ18Oshell, together with geomorphological evidence, we infer that Yamdrok Yumtso was a closed lake system, and we estimate its possible extent during the interval of high lake-level. In addition, we speculate that the water level of Yamdrok Yumtso at this time exceeded 4448.9 m a.s.l., but was less than 4451 m a.s.l., and that the major separation of various components of the Yamdrok Yumtso system occurred after 1.2 kyr BP.

中文翻译：

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青藏高原南部羊卓雍错中全新世古水化学和古水文，由腹足动物木耳化石贝壳δ18O和δ13C重建

湖泊的古水化学和古水文变化很少从腹足类木耳的化石壳中重建，这是一个新的、具有潜在高分辨率的环境档案。我们对青藏高原南部羊卓雍措湖附近裸露的河湖沉积物中的麦冬壳进行了地球化学和稳定同位素研究。我们的目标是确定沉积环境、古湖水化学和水文状况。AMS 14C 和 OSL 测年表明，羊卓雍错的湖面阶段高于今天的水平，发生在约 4.7-1.2 cal 期间。基尔 BP。木耳化石贝壳的Sr/Ca、δ13C和δ18O分析结果表明，湖泊水位波动主要受印度夏季风变化的控制；全新世中期至晚期蒸发量减少也是原因之一。此外，基于Radix sp.之间的地球化学关系。贝壳和湖泊周围水体中，利用木耳化石贝壳重建的δ18OP古水和Sr/Ca古水的值分别为-8.2‰～-5.1‰和0.0012～0.0057。进一步，根据δ18Oshell值，结合地貌证据，我们推断羊卓雍错是一个封闭的湖泊系统，我们估计了它在高湖水位区间可能的范围。此外，我们推测此时羊卓雍错水位超过4448.9 m asl，但小于4451 m asl，羊卓雍错系统各组分的主要分离发生在1.2 kyr BP之后。