稳定钨同位素（δ186/184W）是示踪地表物质循环、重建古海洋环境方面极具潜力的新兴地球化学指标。明确稳定钨同位素在海洋中的源汇过程是进一步应用该指标的基础。研究表明，现代海洋中河流输入是钨的主要来源，非硫化沉积与铁锰氧化物和氢氧化物有关的吸收是钨的主要汇，但不同形式非硫化沉积汇的通量和钨同位素特征尚不清楚。热液沉积物中富含热液来源的铁锰氧化物和氢氧化物，沉积过程中可能从海水中吸附大量钨，形成钨的自生富集，可能是海洋重要的钨汇之一。文章选取位于南太平洋Lau弧后盆地的ODP 834A热液沉积物钻孔样品为代表，分析其钨同位素组成特征，并在此基础上估算了全球热液沉积钨汇通量。ODP 834A钻孔中较高的W/Th表明该钻孔沉积物中碎屑来源钨的贡献极少。结合样品的W/Mo、稀土元素配分等主微量元素特征及稳定钨同位素组成，推断ODP 834A钻孔沉积物中W主要由铁锰氧化物在沉积过程中从海水中吸附而来，其中锰氧化物吸附占主导。ODP 834A钻孔沉积物与海水之间的表观钨同位素差异小于铁锰氧化物吸附与海水之间的平衡分馏值，可能与高沉积速率和沉积通量导致的瑞利效应有关。文章结合钻孔样品的W/Mn值，利用全球热液Mn通量计算出热液沉积作为海洋钨汇的通量不到河流输入通量的5%，这表明海洋中还存在其他形式的主要钨汇。
Stable tungsten isotopes (δ186/184W) are a promising new geochemical proxy for tracing surface material cycles and reconstructing ancient ocean environments. A clear understanding of the source-sink system of stable W isotopes in the ocean is essential for expanding the application. Research indicates that riverine input constitutes the primary source of W in modern oceans, while non-euxinic sediments serve as the main sink. However, the fluxes and isotopic characteristics of different types of non-euxinic sediment sinks remain unclear. Hydrothermal sediments, enriched in hydrothermal sourced iron-manganese oxides, can adsorb significant amounts of W from seawater during sedimentation, resulting in authigenic W enrichment and making them a potentially significant sink. This study analyzed hydrothermal sediment samples from ODP Site 834A in the Lau Basin, South Pacific, to estimate the contribution of hydrothermal sediments to the global oceanic W budget. The high W/ Th in the samples suggests minimal detrital input, while the W/Mo ratio, rare earth element distributions, and δ186/184W values indicate that W in the sediments was primarily adsorbed from seawater by iron-manganese oxides, with manganese oxides playing
a dominant role. The lower-than-expected isotopic fractionation between sediments and seawater may reflect porewater effects driven by rapid sedimentation and high depositional flux. Based on the W/Mn ratios and global hydrothermal Mn fluxes, the hydrothermal sediments W sink flux is estimated to constitute less than 5% of the total riverine input, implying the presence of other unrecognized major W sinks.
