晚第四纪长江和黄河物质在东海外陆架的沉积记录及其对环境变化的响应

Based on the recent research findings of the late Quaternary marine geology on the East China Sea shelf and source features of Changjiang and Huanghe river sediments, this project aims to investigate the late Quaternary shifts of major sediment provenances of three cores (SFK-1, TBF-1 and SHD-1) retrieved from the outer shelf of East China Sea. In particular, the late Quaternary sedimentary.records on the outer shelf of the Changjiang and Huanghe will be revealed and the riverine sediment source-to-sink processes constrained by the changes of sea level, oceanic circulation, enotectonic movements and monsoon climate will be emphasized. The major research methods include detrital garnet assemblages and U-Pb ages of zircons from coarse sediment （＜4φ）samples, and elemental compositions in different chemical phases and Sr-Nd isotopes of the residues in clay fraction of fine sediment （＞4φ）samples. Meanwhile, the formation mechanism of the Quaternary sedimentary system on the outer shelf and its relation with the environmental changes will be discussed in the project. This study will provide more constraints and deepen our understanding on the source-to-sink process and land-sea interaction in the river-dominated marginal seas during the late Quaternary.

基于东海外陆架晚第四纪沉积最新研究成果，应用长江、黄河等河流端元物源特征，通过东海外陆架3个地质钻孔（SFK-1、TBF-1和SHD-1孔）的粗粒沉积物（＜4φ）单颗粒标型矿物化学特征、锆石U-Pb年龄和细粒沉积物（＞4φ）黏土粒级多相态地球化学及其残渣态Sr-Nd同位素物源示踪对比研究，识别晚第四纪长江和黄河及浙闽河流等陆源碎屑物质在海平面、海洋环流、区域新构造运动、全球气候剧烈波动的背景下在外陆架的沉积记录，探讨东海外陆架晚第四纪沉积体系形成机制及其与环境变化关系，为河控型陆架晚第四纪的陆源沉积源汇体系和海陆相互作用研究提供借鉴。

基于项目承担人在东海外陆架晚第四纪沉积研究基础，结合在中国陆源大型河流长江、黄河及东部小型河流的河流端元成因矿物的物源特征，通过东海外陆架代表性地质钻孔的不同粒级沉积物的标型矿物化学、锆石U-Pb年龄、多相态地球化学及Sr-Nd同位素物源示踪对比研究，识别出晚第四纪陆源陆源碎屑物质在冰期-间冰期旋回引起的海平面波动、海洋环流、区域新构造运动共同作用下，东海外陆架的年代地层、生物地层、层序地层等沉积记录，通过类别分析、定量分析，探讨东海外陆架200 ka以来沉积体系形成机制及其与环境变化关系，其中，冰期旋回中低海平面时期，东海外陆架海相沉积的发现，黄河和长江物质在不同海平面时期在陆架沉积分布，为为河控型陆架晚第四纪的陆源沉积源汇体系和海陆相互作用研究提供借鉴。