中天山地块南北两缘的韧性剪切带  

Ductile Shearing Zones Occurring along the Northern and Southern Boundaries of the Central Tianshan Block

作　　者：杨天南[1] 李锦轶[1] 文中田 冯晓飞 王瑜[4] 孙桂华[1] 高立明[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国冶金地质勘察总局山东局一队,淄博255200 [3]中国建材工业地质勘察中心新疆总队,乌鲁木齐830002 [4]中国地质大学,北京100083

出　　处：《地质学报》2004年第3期310-318,i005,i006,共11页Acta Geologica Sinica

基　　金：国家重点基础规划研究项目 (编号 2 0 0 1CB40 980 0 )的部分成果

摘　　要：本文详细描述了天山中段沿乌鲁木齐—库尔勒公路后峡—乌瓦门段的构造变形特点。综合室内外观察研究结果 ,在中天山地块南、北缘 ,及内部的乌拉斯台地区鉴别出三条规模较大的韧性剪切带 :中天山北缘剪切带前人已有研究 ,出露宽达 10 km的右行斜冲剪切带 ,见大量糜棱岩、超糜棱岩 ;乌拉斯台剪切带中的糜棱岩宽超过 2 0 0 m,具有左行走滑运动特点 ;中天山地块南缘剪切带宽度达 5 km,内部发育大量闪长质糜棱岩、超糜棱岩 ,运动方式为左行斜冲。中天山块体南北两侧的脆性边界断层与糜棱岩带变形中心基本重合。这些剪切带具有相当大的走滑位移量 ,指示天山各地质单元间目前的空间关系可能是走滑拼接的结果。研究天山造山带内剪切带的展布、运动方式、总变形量 ,对于恢复各地质单元的初始位置。This paper described in detail the structural features of the central Tianshan block along Houxia-Wuwamen section of the Wulumuqi-Korla highway. Basing upon field and microstructural observations, three ductile shearing zones associated with the Central Tianshan Block are identified. The ductile shearing zone occurred along the Northern Margin of the Central Tianshan block has been studied before, and is dextral with a width up to 10km. The Wulasitai ductile shearing zone occurred within the Central Tianshan block, and is a sinistral one, where its mylonite has a width of 200 m. The ductile shearing zone occurred along the southern margin of the Central Tianshan block is presented as a lot of dioritic mylonite and ultra mylonite. Shearing criteria such as S-C fabric indicated that it is a sinistral shearing zone. The boundary faults that were used to define the Central Tianshan block developed along the shearing center of the northern or southern ductile shearing zones respectively. Above shearing zones must have very large strain accumulations, suggesting the amalgamation of the tectonic units of the Tianshan range result from strike sliding in a great degree. It is significant to study the space distribution, kinematics and total strain accumulation of the ductile shearing zones for reconstruction of the tectonics and paleo-geography of the Tianshan range.

关 键 词：剪切带 运动学 中天山地块 糜棱岩 

分 类 号：P542[天文地球—构造地质学]