Fossil shells of the gastropod sp. are widespread in the sediments of wetlands and lakes, and in fluvial and lacustrine depositional sequences on the Tibetan Plateau (TP). Although aragonite shells of sp. are a potentially valuable archive of information on environmental changes, the living environment of sp. and the significance of its shell geochemistry (e.g., Sr/Ca, Mg/Ca, δC δO) are unknown or disputed. In this study we investigated living specimens of the dominant species of sp. () in rivers, wetlands, and lakes on the TP, together with its fossil shells in the Holocene lacustrine sediments of Nam Co (NC) on the TP. Specifically, we measured the values of Sr/Ca, Mg/Ca, δC and δO of the modern and fossil shells. Our results indicate that the hydrochemical composition and electrical conductivity of the ambient water significantly affect the survival and abundance of . . The environmental tolerance of . can be ordered as: carbonate-type > sulfate-type > chloride-type. Additionally, we speculate that the upper threshold of electrical conductivity for the survival of . does not exceed ∼4544 μS/cm. Furthermore, we established the relationship between modern . shells and its host water and developed -based transfer functions (TFs). To assess their potential for paleoenvironment reconstruction, the TFs were then applied to fossil shells of . collected from a Holocene lake sediment profile from a terrace around NC. We show that Sr/Ca in . is a potentially reliable proxy for reconstructing the Sr/Ca of the paleo-water (Sr/Ca) and the paleoconductivity. By contrast, Mg/Ca in . cannot be used for environmental reconstruction. δC in . primarily reflects the δC of the host water. When the host water is deficient in HCO + CO (<280 mg/L) there is an increased supply of dissolved carbon derived from organic sources to the shells of . . Overall, δO in . is likely one of the most reliable indicators for the δO of the host water of the lakes on the TP.

中文翻译：

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青藏高原腹足动物贝壳与现代水体的地球化学关系及其古环境意义

腹足动物的化石壳。广泛存在于湿地和湖泊的沉积物中，以及青藏高原（TP）的河流和湖泊沉积层序中。虽然文石壳 sp。是关于环境变化、sp的生活环境的潜在有价值的信息档案。其壳层地球化学（例如，Sr/Ca、Mg/Ca、δ13C δ18O）的意义尚不清楚或存在争议。在这项研究中，我们研究了主要物种的活体标本。 () 存在于青藏高原的河流、湿地和湖泊中，以及青藏高原纳木错全新世湖相沉积物中的贝壳化石。具体来说，我们测量了现代贝壳和化石贝壳的 Sr/Ca、Mg/Ca、δ13C 和 δ18O 值。我们的结果表明，环境水的水化学成分和电导率显着影响水体的生存和丰度。 。的环境耐受性。排列顺序为：碳酸盐型>硫酸盐型>氯化物型。此外，我们推测生存的电导率上限。不超过~4544 μS/cm。此外，我们建立了现代之间的关系。壳及其宿主水和开发的基于传递函数（TF）。为了评估它们在古环境重建方面的潜力，随后将 TF 应用于化石贝壳。从北卡罗来纳州周围阶地的全新世湖泊沉积物剖面中收集。我们证明了 中的 Sr/Ca。是重建古水 Sr/Ca (Sr/Ca) 和古电导率的潜在可靠代理。相比之下， 中的 Mg/Ca 。不能用于环境重建。 δ13​​C 中。主要反映宿主水的 δ13C。当宿主水中缺乏 HCO + CO (<280 mg/L) 时，来自有机来源的溶解碳供应到贝壳中就会增加。 。总体而言，δ18O 在 .可能是青藏高原湖泊宿主水 δ18O 最可靠的指标之一。