喇嘛苏铜矿区中酸性岩体微量元素特征及其成因分析

Characteristics of Trace Elements of Intermediate-acid Intrusive Bodies and its Genetic in Lamasu Copper Deposit

根据喇嘛苏铜矿中酸性岩体新鲜样品的微量元素含量测试结果，岩体中M的平均含量接近于维氏值，而Ti、Cr、V则低于维氏值；高场强元素含量为（611．25～1210．11）×10^-6，平均值为1031．211×10^-6；大离子亲石元素含量为（1041．05～2708．61）×10^-6，平均值为1845．15×10^-6；Rh、Ba、K、La、Sm和Th的含量较高，Ta、Nb、Ti较低，而且Th含量远远大于Ta含量；在花岗岩类岩石的非活动性元素构造环境判别图上，所有的样品点均落入火山弧花岗岩区域内，说明本区花岗岩类岩石为造山带的I型花岗岩，属正常的钙碱性大陆边缘弧花岗岩类岩石，是产于消减带而来自壳源的火成岩，在其形成过程中有可能有洋壳物质和流体的加入，同时也混染了围岩。

According to the test results of the trace elements content of the fresh samples from intermediate-acid intrusive bodies in Lamasu copper deposit, the average content of Ni is close to the value of Vickers, but the value of Ti , Cr , V is inferior to the value of Vickers. The content of high field strength elements is between 611. 25 ×10^-6 and 1 210. 11×10^-6 with the average value of 1 031. 211 ×10^-6. The content of large ion lithophile elements is between 1 041. 05 x 10 -6 and 2708.61 ×10^-6 with the average value of 1 845. 15 ×10^-6. The content of the elements such as Rb, Ba, K, La, Sm , Th is higher than others, however, the content of the Ta, Nh , Ti is lower. Besides, the content of Th is much higher than Ta. All samples points are located at the area of volcanic arc granite in the tectonic discrimination diagram of non-active elements of porphyry. It is illustrated that, the granitoid in this area is I -type granite of orogenic belt, and belongs to the normal calcium alkaline continental margin arc granitoid. And it is the rock that is generated in subduction zone and comes from the Earth＇ s crust. The granitoid in this area may be blended by the oceanic crust material and fluid during its forming process and also mixed with surrounding rock as welL