东疆哈尔里克变质地带变质作用特征及形成构造环境研究

CHARACTERISTICS OF METAMORPHISM IN THE HARLIK METAMORPHIC BELT,EAST XINJIANG,AND ITS TECTONIC ENVIRONMENT

本文通过对哈尔里克变质地带的变质岩石学，变质矿物及矿物包裹关系的研究，确定该变质带的形成曾经历了晚古生代中、晚石炭世的高温—低压型的区域热变质作用和晚石炭世末期中温—中压型的断裂区域变质作用，且后者叠加改造了前者。前者温度为９２２～７８０℃，后者可划分出四个递增变质带，温压为４５０～６７０℃和２．３～４．１ｋｂ。这一研究反映了哈尔里克泥盆纪火山岛弧经过了由拉伸作用到碰撞挤压造山引发的Ａ型俯冲作用演变过程。

Based on researches of metamorphic rocks and minerals in the metamorphic belt in Harlik,the authors suggest that the metamorphic belt underwent two metamorphic stages.The first stage was the regional thermal metamorphism of high temperature (T=922￣780℃) and low pressure during the early middle Carboniferous of late Paleozoic.The second stage was the regional faulting metamorphism of medium tempeature and medium pressure (T=450～670℃,p=2.3￣4.1Kb) during the end of Carboniferous.The second stage can be divided into four metamorphic zones.Detailed research suggests the following tectonic evolution model:Thermal metamorphism was related to intra island arc tension,while regional faulting metamorphism was caused by A type subduction in the process of collisional orogeny.