晚中新世-早更新世南海底层水演变的Nd同位素记录

南海深海沉积物记录了海盆构造演化、太平洋水团性质变化的重要信息。ODP1148钻孔位于南海北部，巴士海峡西侧，水深超过三千米，保存了渐新世以来的连续沉积记录，为南海的形成、演化及其环境变化提供了最佳的研究材料。本研究主要利用ODP1148岩芯从1Ma-8Ma所对应的沉积物样品，按10万年左右的分辨率提取其记录南海底层水性质的Fe-Mn氧化物中Sr-Nd-Pb同位素及REEs等微量元素组成，了解晚中新世到早更新世时期南海底层海水的演变历史，探讨巴士海峡上升过程南海底层水与太平洋深层水在地球化学性质上的差异变化，以及巴拿马海峡关闭后南极底部水团（AABW）向北渗透对南海底层水的影响。本项目对于完善南海海盆演化年龄模式，了解南海扩张结束后南海底层水性质的变化，以及西太平洋深层水团演化都具有重要的科学价值。

Nd isotopes preserved in ferromanganese oxide in marine sediments have become an important tool for tracing the evolution of ocean water mass circulation through time. Nd isotopes extracted from bulk sediments by using hydroxylamine hydrochloride (HH) solution can provide high resolution sedimentary records of sea water information.ODP1148 lies to the northern South China Sea and beyond three kilometer water depth, preserving sequential sediment record since Oligocene. It is one of the best optimum material for studying the formation, evolution and paleoenvironment of South China Sea. In this study we select 1Ma-8Ma ODP site 1148 sediment samples, according to the 0.1Ma resolution, extracting the Sr-Nd-Pb isotopes and rare earth elements composition from ferromanganese oxide in these sediments. The purpose is to relize the evolution of the bottom water during the Late Miocene to early Pleistocene in the South China Sea and discuss the variation of bottom water mass in South China Sea after the Bashi Strait uplift. Through this study, it is helpful to improve the knowledge of the tectonic evolution age model of South China Sea, and also can reconstract the West Pacific deep water paleocirculation.