阿尔泰山南缘东段玛因鄂博韧性剪切带特征及运动学、动力学分析  

THE CHARACTERISTICS OF MAYINERBUO DUCTILE SHEAR ZONE AND ITS TECTONIC AND KINEMATIC ANALYSIS

作　　者：张小林[1] 周刚[1] 罗世宾[1] 郑开平[1] 

机构地区：[1]新疆维吾尔自治区地质矿产勘查开发局第四地质大队,新疆阿勒泰836500

出　　处：《新疆地质》2007年第1期26-33,共8页Xinjiang Geology

摘　　要：玛因鄂博韧性剪切带位于阿尔泰山南缘额尔齐斯大断裂东段,玛因鄂博断裂以北,带内岩石糜棱岩化强烈,线理、面理构造发育,局部剪切变形明显部位发育S-C组构、σ型和δ型残碎长石斑晶系,均指示为左行韧性剪切变形.带内变形岩石宏、微观特征显示:玛因鄂博韧性剪切带是以压扁变形为主的左行剪切变形,韧性变形深度相当于地壳10～15km深处,温度约300～450℃,压力在0.25～0.40GPa,是一种发生在地壳中-浅构造层次和中-低温度、中等压力条件下的韧性-脆性变形,其变形变质作用相当于中低绿片岩相,局部达高绿片岩相;剪切主应力方向为NEE向,约83°.剪切位移量和剪切带宽度大致相当,总剪切位移量约9.2～11.5km.该韧性剪切带的剪切活动持续时间较长,高峰期为290～270Ma,而其最后结束时间为230Ma左右.Mayinerbuo Ductile Shear Zone locates at the north of Mayinerbuo Fault of in the eastern part of regional Erqishi Fault in the Southern Altai Mountain Range. The country rocks experienced extensive mylonization, with well developed lineation, foliation, characterized with S-C fabric deformation, type oand 6 type skeleton feldspar phenocryst series, indicating the counter-clockwise ductile shear deformation. The macro and micro features of the deformed rocks indicate that the Mayinerbuo Ductile Shear Zone is a counter-clockwise flattening shear deformation, with ductile shear deformed depth at 10 -15 km in the crust, temperature at 300-450 ℃ and pressure at 0.25-0.40 GPa, belonging to the ductile-brittle deformed shear zone occurred at intermediate-shallow tectonic zone, with intermediate-low temperature and intermediate pressure. The deformation and alteration are similar to the intermediate-low green-schist facies, and up to high green schist facies locally. The dominate direction of the shear stress is at NEE, about 83°, with the total shear displacement about 9.2 -11.5 km, almost similar with the width of the shear zone. The ductile shear deformation lasted a relatively long period of time, with prime time at around 290 - 270 Ma, and ended at around 230 Ma.

关 键 词：玛因鄂博 韧性剪切带 特征 运动学 动力学 分析 

分 类 号：P542[天文地球—构造地质学]