摘要
甲布钾长花岗岩体位于西藏措勤盆地中部,出露面积约160km^2,主要由中粗粒、中粒似斑状和细粒似斑状黑云母钾长花岗岩组成.岩石以富硅、钾,贫铁、镁、钙为特征,分异指数(DI)平均达92.71,里特曼指数变化范围在1.22~2.10,ALK平均值为7.5,K2O/Na2O比值均大于1.55,属高钾钙碱性系列花岗岩.稀土及微量元素地球化学特征显示,花岗岩是以壳源为主的壳幔混源型.根据不同测试方法测定岩体同位素年龄在65.1~72.58Ma,属于晚白垩世.
Jiabu moyite body is located in the center of Coqen basin, Tibet, which approximately covers an area of 160 km^2.It is mainly composed of medium grianed to medium - coarse grianed , medium porphyritic and fine-grained porphyritic biotite Moyite. The granites are rich in Si, K and deficient in Fe, Mg, Ca.The average of Differentiation Index is 92.71, with Rittman Index ranging between 1.22 and 2.10,the average of ALK is 7.5 and K2O/Na2O 〉 1.55,which belongs to high-K calcalkaline series. The characteristics of REE and trace elements display that the original magma of the granites is crust-mantle mixtures-mostly coming from crust. With many kinds of testing methods ,we know that the isotopic age is between 65.1 Ma and 72.58 Ma, which belongs to Late Crataceous.
出处
《新疆地质》
CAS
CSCD
2008年第2期189-194,共6页
Xinjiang Geology