东海内陆架EC2005孔重矿物组合特征及其物源指示意义  

HEAVY MINERAL ASSEMBLAGES IN CORE EC2005 IN THE INNER SHELF OF EAST CHINA SEA AND THE ORIGIN

作　　者：董江[1,2] 李安春[1] 徐方建[2] 黄朋[1] 张凯棣[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]中国石油大学(华东)地球科学与技术学院,青岛266580

出　　处：《海洋与湖沼》2015年第6期1292-1303,共12页Oceanologia Et Limnologia Sinica

基　　金：国家自然科学重点基金项目;41430965号;国家自然科学基金项目;41106040号;41406064号

摘　　要：为探讨东海内陆架17.3ka BP以来的重矿物含量变化及其物源指示意义,对东海内陆架南部泥质沉积中心EC2005孔的沉积重矿物进行了鉴定和分析。结果表明:(1)在0.063—0.25mm粒级沉积物中,重矿物含量平均值为27.3%,变化范围为3.7%—89.6%,重矿物含量较高的部分均出现在自生黄铁矿富集的层位;(2)片状矿物、含铁氧化物、角闪石族矿物、绿帘石族矿物、白云石、辉石族矿物、变质矿物、蚀变矿物和自生黄铁矿占重矿物颗粒总数的96.0%以上,但其含量变化很大;(3)以重矿物分布特征为依据将岩心划分为Ⅰ—Ⅴ五个沉积层段,各层段对应的特征矿物分别为片状矿物、白云石、片状矿物、自生黄铁矿和榍石。结合粒度、AMS14C年代及西太平洋海平面变化等数据对物源进行分析,结果表明:自17.3ka BP以来,EC2005孔沉积物源主要是长江,其次还可能受到瓯江等浙江沿岸河流所输运物质的一定影响。Heavy minerals in the bore hole EC2005, located in the southern center of mud area in the inner shelf of East China Sea, was identified and analyzed for their significance of provenances since 17.3ka BP. The results show that in the sediment of grain size 0.063—0.25 mm, the average content of heavy minerals is 27.26% in range of 3.66%—89.62%. High content of heavy minerals appears in the horizon of rich authigenic pyrite. The heavy minerals included lamellar mineral, metallic mineral, amphibole, epidote, dolomite, pyroxene, typical metamorphic minerals, altered minerals and authigenic pyrite, and they altogether took more than 96.00% of the total amount, but varied in content through core EC2005.. The distribution of heavy minerals can be divided into five units from the Unit Ⅰto Unit Ⅴ from bottom to top; the characteristic minerals are lamellar minerals, dolomite, lamellar minerals, authigenic pyrite, and titanite. In combination with AMS^14 C dating and the sea level data in the west Pacific Ocean, we analyzed the provenance of the sediment. Results show that, during 17.3—0ka BP, the place of the core received primarily from Changjiang（Yangtze） river, and also some from along-coast current off Zhejiang Province.

关 键 词：重矿物 物源 EC2005孔 东海内陆架 

分 类 号：P736.212[天文地球—海洋地质]