青岛胶州湾口海底隧道火成岩岩石地球化学及成因  

STUDY OF GEOCHEMISTRY AND CAUSE OF FORMATION OF IGNEOUS ROCKS OF CROSS-HARBOUR TUNNEL IN THE MOUTH OF JIAOZHOU BAY OF QINGDAO

作　　者：韩宗珠[1] 宋红瑛[1] 张贺[1] 丁蒙蒙[1] 

机构地区：[1]中国海洋大学海洋地球科学学院,山东青岛266100

出　　处：《海洋湖沼通报》2012年第2期11-21,共11页Transactions of Oceanology and Limnology

基　　金：国家自然科学基金项目(41072152);中国海洋大学OUC_SRTP项目(0811010401)资助

摘　　要：胶州湾是位于新华夏隆起带次级构造单元胶南隆起区和胶莱凹陷的交接部的断陷盆地,团岛——薛家岛海底隧道开挖段有大量火成岩出露。本文对采集于海底隧道的8件岩石样品进行了岩石学和地球化学研究,按岩性将其分为偏基性岩类和偏酸性岩类两类。其中除样品F4-5(辉绿岩)外,偏基性岩类均落入岛弧型钙碱性玄武岩区域内;而偏酸性样品均落入火山弧花岗岩区域,显示其原岩起源于同一种火山弧的环境。稀土元素标准化曲线表明,其岩石轻重稀土元素分馏比较明显,其LREE/HREE也显示样品的分异作用较强。岩石样品的地球化学特征研究证明,研究区域的玄武质岩体为遭受地壳混染的岛弧型性玄武岩,应为在燕山晚期花岗质脉岩沿着青山群中构造薄弱带侵入,与地壳物质发生混染作用形成的。Jiaozhou Bay is a rifted basin which is located on the part that connected with the subprime tectonic units of Jiaonan uplift areas in the Chinese upwelling area and Jiaolai sag, and large amounts of igneous rock exposed at the excavation section of Tuandao-xuejiadao cross-harbour tunnel. In this paper, the petrology and geochemistry of the 8 rock samples collected from Cross-Harbour Tunnel were researched, which can be roughly divided into basic and acidic rocks in two categories. Apart from F4--5, basic classes fall into the island arc type calcium alkaline basalt in the region; and acidic samples fall into the volcanic arc granite area, and it shows its original rock originated from a volcanic arc environments. Rare earth element standardization curve of Samples shows that its severity of fractionation of rare earth elements is more obvious, the LREE/HREE also shows strong differentiation of the samples. In addition, through the research on geochemical characteristics of rock samples proved that the basaltic rock in research area are the arc tholeiitesuffered crustal contamina- tion, which should be formed in the Late Yanshan period, when the intrusion of granitic dikes along the Castle Peak farm weak zone and crustal material happened contamination.

关 键 词：胶州湾 海底隧道 火成岩 岩石地球化学 成因 

分 类 号：P581[天文地球—岩石学]