内蒙古锡林郭勒杂岩岩石学特征及其变质作用的p-t条件

Petrology and metamorphic p-t condition of Xilin Gol complex, Inner Mongolia, China

锡林郭勒杂岩出露于华北地台北缘晚古生代褶皱带内 ,形成于 1.3～ 1.0Ga ,主要由黑云斜长片麻岩、角闪斜长片麻岩、斜长角闪片岩以及变粒岩夹透镜状或脉状斜长角闪岩组成 ,具角闪岩相变质 ,原岩以钙碱性系列火成岩为主。通过对其中角闪岩及片麻岩中的长石、角闪石的矿物化学研究 ,计算出其变质作用发生的温度为 5 40～ 5 5 0℃ ,压力为 0 .5～ 0 .

Exposed on the northern edge of North China Platform, Xilin Gol complex has an age of 1.3～1.0 Ga. It is mainly composed of hornblende-plagioclase gneiss and biotite-plagioclase gneiss, plagioclase-hornblende schist, and amphibolite. Subjected to metamorphism of hornblende subfacies, its protolith comprises mostly calc_alkaline igneous rocks. This paper deals with mineral chemistry of amphiboles and feldspars in the complex and indicates that the metamorphism took place at temperature of 540～550℃ and pressure of 0.5～0.6 Gpa.