17000年以来冲绳海槽中部沉积物物源演化及其古环境记录  

SEDIMENT PROVENANCE AND PALEOENVIRONMENT RECORDS OF THE CENTRAL OKINAWA TROUGH FOR THE LAST 17 000YEARS

作　　者：王佳泽 李安春[1] 黄杰[1] 

机构地区：[1]中国科学院海洋研究所海洋地质与环境重点实验室,青岛266071 [2]中国科学院大学,北京100049

出　　处：《海洋地质与第四纪地质》2013年第6期105-114,共10页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金项目(40776030)

摘　　要：基于AMS^14C高精度测年，采用粒度与黏土矿物分析方法，对冲绳海槽中部岩心OK104沉积物的物源以及古环境演化进行了研究。结果表明，自17000a以来，岩心陆源物质为多方物源混合的结果，而主要物源供应区为中国东部长江与黄河等主要河流入海物质以及台湾东西部主要河流入海物质。但是不同时期．各物源相对贡献量有所不同．17～13．4ka期间，长江与黄河入海物质输送以及台湾河流物质均对研究区有一定的影响；13．4～u．3ka时期，长江与黄河物质输入开始降低，台湾河流入海物质有所增加；11．3～7．5ka以来，长江与黄河入海物质的影响有所加强；7．5～5．5ka，台湾物质影响占据主导地位；5．5ka至今，沉积物主要来自台湾东部地区以及长江入海沉积物。同时识别出高岭石主要来源于中国大陆东部河流入海物质。此外，通过提取沉积物中对沉积环境变化较为敏感的优势粒级组分，发现沉积物主要以悬浮方式发生运移。而中国东部河流入海物质向海槽的输运主要与冬季风引起的环流相关，因此，以具有相对单一物源的高岭石含量作为指示东亚冬季风演化的指标，并识别出自17ka以来中国东部地区5个冬季风主要加强期。Based on the data of grain size and clay minerals coupled with precise AMS 14C dating , this pa- per deals with the provenance and paleoenvironment evolution of the Central Okinawa Trough for the last 17000a with the samples from the Core OKI04. The results indicate that the terrigenous sediments in the Central Okinawa Trough are mainly from the East China Sea carried by both the large rivers from East China （the Yangtz River and Yellow River） and the small rivers from east and west Taiwan. The two ma-for provenances have different contribution to the study area in different periods. During the period of 17- 13.4 ka, sediments were mainly from the large rivers in East China （the Yangtz River and Yellow River） and the small rivers in east and west Taiwan ; In the period of 13.4 -11.4 ka, sediments from west Tai- wan increased; in the period of 11.4-7.5 ka, the influence of the Yangtz river and Yellow river increased; during the period of 7.5-5.5 ka, the sediments in the study area were mainly affected by the Taiwan source; since 5.5 ka, the sediments were mainly from East Taiwan and Yangtz River. Our study also re- veals that Kaolinite was mainly from the large rivers in the Eeast China mainland. Besides, the environ- mentally sensitive grain-size populations suggests that the sediments were transported mainly in a suspen- ded manner. The transportation of the suspended sediments from the main rivers in East China is related to the ocean circulations driven by the winter monsoon. In this study, kaolinite content is used as the indica- tor of the winter monsoon＇s evolution under the assumption that the provenance remains unchanged, and thus 5 strengthened periods of winter monsoon were identified since 17 000 a in the East China mainland.

关 键 词：粒度 黏土矿物 物源 东亚冬季风 冲绳海槽 

分 类 号：P736.2[天文地球—海洋地质]