摘要
为揭示柴北缘复杂的构造演化特征，用 X射线荧光光谱（XPF）、电感耦合等离子质谱（ICP-MS）等方法对赛什腾山花岗闪长岩、花岗岩和二长花岗岩进行了系统的全岩地球化学与微量元素研究。结果表明，赛什腾山岩体富含 SiO2（64.23％～71.56％）、Al2 O3（14.03％～18.36％）；K2 O／Na2 O值平均为0.48，具准铝质-弱过铝质、钙碱性特征；岩石相对富集 Th、U、Sr，亏损 Ta-Nb、Ti、Pb；稀土总量变化幅度较大（74.29×10－6～169.11×10－6），轻重稀土分馏明显，弱 Eu 负异常特征；主微量元素图解及对比分析显示出Ⅰ型花岗岩特点。结合其他资料，可以认为赛什腾山岩体形成于岛弧环境，是地幔上侵混染了大陆地壳形成的产物，该花岗岩侵位时南祁连洋尚未闭合。
In order to reveal complicated tectonic evolution characteristics of northern margin of the Qaidam Basin,XPF and ICP-MS were used to study major and trace element geochemistry of the Saishiteng granitic diorite,granite and monzogranite in this paper.The results indicate that those granitoids contain high contents of SiO2（64.23%-71.56%）and Al2 O3（1 4.03%-1 8.36%）with the average K2 O/Na2 O ratio of 0.48,suggesting that the granitoids have metaluminous-weak peraluminous and calc-alkaline characteristics.It can be seen on the primitive mantle-normalized trace element spi-dergrams that they are relatively rich in Th,U,and Sr,relatively depleted in Ta,Nb,Ti,and Pb.Their REE contents vary largely from 74.29×1 0-6 to 1 69.1 1 ×1 0-6,with obvious fractionation between LREE and HREE,and weak negative Eu anomalies on the chondrite-normalized REE patterns.Both of their major and trace elements show characteristics of the I-type granite.With the combination of previous data,it is believed that the Saishiteng intrusive body was formed in the is-land arc environment by the emplacement of the magma derived mainly from the mantle with contamination of the continen-tal crust when the South Qilian Ocean was not closed yet.
作者
辛存林
谢庆豪
董凯
廖建栋
XIN Cun-lin XIE Qing-hao DONG Kai LIAO Jian-dong(College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China College of Geography and Resources, China University of Geosciences （Wuhan） , Wuhan 430074, China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2016年第5期908-916,共9页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金项目(41262001)
甘肃省科技支撑项目(1104FKCA116)
关键词
Ⅰ型花岗岩
地球化学
岛弧
赛什腾山
Ⅰ-type granite
geochemistry
island arc
Saishiteng mountain
