阿尔泰海西造山带区域变质作用类型与地壳演化

Metamorphic Types and Crustal Evolution of HercynianOrogenic Belt in Altai Region, Xinjiang

新疆阿尔泰海西造山带主要发育两期区域变质作用。第一期变质作用属于区域低温动力变质作用类型,以形成低绿片岩相矿物组合为特征,变质温度较低,而应力作用较强,是造山作用初期热流活动较弱,构造变形强烈环境下的产物。第二期变质作用属于区域动力热流变质作用类型,以形成典型的递增变质带为特征。这一期代表造山作用主期热流活动强烈,伴随有构造变形和岩浆活动。不同的变质作用类型代表了不同的大地构造环境,记录了造山带的演化历史和动力学过程。

The Altai Hercynian orogenic belt in northern Xinjiang has experienced two stages (regional) metamorphism. The first stage belongs to regional low-temperature dynamic metamorphic type and is characterized by typical metamorphic mineral assemblage of low greenschist facies with low metamorphic temperature and strong stress-induced recrystallization which represents weak crustal heat flow and strong structural deformation during early stage of an orogeny. The second stage of metamorphism belongs to regional dynamic heat flow metamorphic type and is featured by typical progressive metamorphic belt which marks the strong crustal heat flow aetion accompanied with intense structural deformation and magma intrusion during the main stage of the orogeny. Different metamorphic types reveal different tectonic conditions and record the evolutionary history and geodynamic process in Altai Hercynian orogenic belt of Xinjiang.