东海外陆架Q43岩心末次冰期矿物学特征及其古环境意义  

Mineral characteristics and their environmental implication during the last ice age in Core Q43 on the outer shelf of the East China Sea

作　　者：金秉福[1] 林振宏[1] 季福武[1] 时振波[1] 张宗雁[1] 

机构地区：[1]中国海洋大学海洋地球科学学院,山东青岛266003

出　　处：《海洋学报》2003年第S2期177-185,共9页

基　　金：国家自然科学基金资助项目(40067013).

摘　　要：对东海外陆架Q43孔(26°33 1401′N,124°12 7107′E°)岩心的沉积层序、粒度参数、碎屑矿物和黏土矿物研究,揭示了东海外陆架末次冰期的滨岸浅水沉积的基本特征.钻孔30～374cm表现为一不完整的滨海相海退层序:下部的细砂质粉砂层,代表滨外浅水低能环境;上部的粉砂质细砂层,代表前滨高能环境,柱样中的一些层位含较多的生物贝壳碎片.沉积物分选系数大,带有混合沉积的特点;碎屑矿物是以普通角闪石-绿帘石-钛铁矿为主的重矿物组合,矿物成熟度低;黏土矿物以高伊利石、低高岭石含量和高伊利石Hw结晶度指数为特征.综合分析表明,沉积物源区近,具有中酸性侵入岩和浅变质岩的物源特点,可能来源于浙闽沿海山地或东海陆架隆起区.沉积物经受过强水动力作用,沉积过程复杂,细砂层部分海绿石可能来自于早先形成物的再搬运.The studies on the sedimentary sequences, grain size composition, detrital minerals and clay minerals reveal the general sedimentary characteristics of littoral zone during the last ice age in Core Q43 (location: (26°33.1401)′N,124°12.7107′E) drilled in the outer shelf of the East China Sea. The regressive sequence of littoral facies from 30 to 374 cm, including fine sandy silt (230～374 cm), and the low hydraulic condition and silty fine sand (30～230 cm), which indicates the high hydraulic condition is not integrated. There are many fragments of shell in some strata position of the core. All the sediments in the core are of high sorting coefficient, hornblende-epidote-ilmenite assemblage and high HP/TRZG ratios. Based on detrital minerals it is unraveled that the sediment is of stable source, and of the traits of intermediate-acidic magmatic rock and metamorphites. These sediments may be derived from the coast of eastern Zhejiang-Fujian or the uplifted area of the East China Sea continental shelf. Clay minerals are of high illite and low kaolimite content which indicate the cool and arid climate condition in the time of sediment conformation. Sediments have experienced strong hydraulic action and sedimentary process is quite complex. Part of glauconites may had been produced by the reworking of older glauconitic sediment.

关 键 词：东海外陆架 末次冰期 重矿物 沉积环境 

分 类 号：P736.3[天文地球—海洋地质]