冲绳海槽粘土粒级沉积物成因及环境意义-IODP331航次后续研究

The compositions and environmental tracing application of clay minerals in East Asian rivers and marginal seas have been well investigated. However, the origins, sources and environment implication of clayey sediments in the continental margin await more clarification, and paticularly, the influence of hydrothermal activity in the Okinawa Trough on clay origins is poorly understood. Based upon previous studies, this project will study the sedimentological and isotopic geochemical compositions of the clay samples taken from the middle (IODP 331) and southern Okinawa trough (ODP 1202B) and the East China Sea shelf, with focus on the influence of hydrothermal activity on clays. By using some novel geochemical proxies, the hydrothermal events and its composition, and the chemical weathering intensity registered in the clays will be revealed. This study will potentially strengthen the recognition of clay origin in marine environment, which may have a significant contribution to the study of land-sea interaction and sediment source to sink process in the East China Sea.

我国东部河流与边缘海的碎屑粘土矿物组成及运用研究取得大量成果，但目前对东海陆架边缘粘土粒级沉积物的不同来源、成因及其环境指示意义的系统研究还很薄弱，尤其缺乏冲绳海槽地区热液活动对碎屑粘土沉积物影响的深入研究。该课题将在前人研究基础上，以IODP331航次在海槽中部热液区采集的大量样品为主要研究对象，同时比较研究东海陆架表层和海槽南部ODP1202B岩芯样品。运用以同位素地球化学为主结合沉积矿物学分析，比较研究冲绳海槽地区粘土粒级沉积物的不同来源与成因，探讨不同成因粘土组成对热液活动不同期次、大陆源区化学风化环境的指示意义。该研究不仅将深化海洋环境中粘土成因认识，对于东海陆海相互作用与沉积物从源到汇过程研究有重要促进意义。

针对该课题主要的科学目标，项目组以海陆结合和从源到汇的研究思路，对IODP331航次、ODP1202和东海开放航次采集的大量样品为主要研究对象，开展了大量沉积矿物学、元素和Sr, Nd, Mg同位素地球化学分析，揭示了冲绳海槽粘土粒级沉积物的不同来源和成因，热液活动对陆源粘土的蚀变改造；我们提出识别热液（蚀变）成因和陆源碎屑来源粘土的沉积地球化学新指标，深化对全球海洋粘土成因特征的认识，为东亚边缘海细颗粒沉积物从源到汇过程和古环境重建研究提供更多科学依据。依托该项目，在国内外核心刊物上共发表研究论文27篇，包括国际SCI论文19篇；培养研究生6名，博士后2名。