西天山造山带双变质带变质变形序列分析——以新疆昭苏县察汗乌苏一带为例

西天山造山带中双变质带以新疆昭苏察汗乌苏一带较为典型,根据变质作用的不同,划分出绿片岩相绢云母-绿泥石带、绿片岩相蓝闪石带、角闪岩相黑云母-普通角闪石带、角闪岩相矽线石-铁铝榴石带等变质相带;按其变质作用以及构造变形程度分为上部层次脆性性构造层、中上部层次、深部层次3种构造层次。根据之间的相互叠加关系,确立了造山带内的岩石主要存在着3期以上构造变形特征;在主要的3期构造变形过程中见有相应的变质矿物,并根据生成的矿物组合与变形之间的相互关系,通过变质矿物先后生成关系与岩石的结构、构造建立了变质与变形序列关系,确立了变质与变形非简单一一对应,而是具有渗透叠加和循环往复的特点。

The Analysis of Metamorphism-deformation Sequence for the Paired Metamorphic Belt in West Tianshan Orogen:An Example from Chahanwusu Area,Zhaosu County,Xinjiang

The paired metamorphic belt of West Tianshan Orogen is more typical in Chahanwusu Area, Xinjiang. According to the difference of metamorphism, this paired metamorphic belt can be divided into several metamorphic facies zone, including sericite-chlorite zone with greeanschistfacies, glaucophane zone with greenschist facies,biotite-hornblende zone with amphibolite facies belt and sillimanite-almandite zone with amphibolite facies. Based on the degree of metamorphism and tectonic deformation, this paired metamorphic belt can be divided into three kinds of structural levels:the brittle structural layer in the upper level, the structural layers in the middle-upper level and the ones in the lower level. After analyzing the superimposed relationship among these structural levels, more than threetimes of tectonic deformation characteristics have been distinguished in the rocks of West Tianshan Orogen. And the corresponding metamorphic minerals for these three tectonic stages in the process of deformation can be observed. And then, the interrelationship between generated mineral association and deformation has been discussed, the relationship between metamorphism and deformation sequence has been established according on analyzing the produce order of metamorphic mineral, the rocks' textures and tectonic. Finally, it's certain that the relationship between metamorphism and deformation is not a simple one-to-one relationship, but has the characteristics of penetration superposition and circulation.