鲁西青邑韧性剪切带运动学涡度及剪切作用类型  

Kinematic Vorticities and Shear Types of the Qingyi Ductile Shear Zone in Western Shandong

作　　者：王新社[1] 张尚坤[2] 张富中[3] 杨崇辉[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质大学地球科学与资源学院,北京100083 [3]山东省地质调查院,山东济南250013

出　　处：《地球学报》2005年第5期423-428,共6页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目(编号:40102017);原地质矿产部"1:5万田黄;土旺幅区域地质调查"项目资助。

摘　　要：青邑韧性剪切带是晚太古代末期发育在鲁西前寒武纪基底花岗岩中一条规模较大的韧性剪切带.剪切带NW走向,面理直立,线理水平,剪切标志反映右行剪切.石英光轴法求得运动学涡度在0.96～0.99之间变化,极摩尔圆法求得糜棱岩化岩石运动学涡度为0.91,初糜棱岩运动学涡度为0.87,糜棱岩运动学涡度为0.81,超糜棱岩运动学涡度为0.60.运动学涡度表明,剪切带剪切作用类型为一般剪切,变形初期以单剪为主,随应变的增大,运动学涡度值逐渐减小,变形的纯剪分量不断增加,最后以纯剪为主.剪切作用类型及三维参照变形分析表明,青邑韧性剪切带属加长-变宽类型的一般剪切带并且在y轴方向上有所增长.韧性剪切在太古代末期克拉通化过程中具有加厚陆壳的作用.The Qingyi ductile shear zone （QDSZ） developed in Late Archean is a large-size ductile shear zone in granite of the western Shandong Precambrian basement. The QDSZ trends NW-SE with nearly vertical foliation and subhorizontal lineation. The shear indicators and quartz c-axial fabrics in the zone imply dextral strike-shearing. Kinematic vorticity numbers in the QDSZ obtained through quartz C-axial fabrics analysis range from 0.96 to 0.99. Kinematic vorticity numbers given by polar Mohr constructions of mylonitic rocks, protomylonite, mylonite and ultramylonite are 0.91,0.87,0.81 and 0.60, respectively. Kinematic vorticity numbers show that the shear type of the QDSZ was at first a general shear, and the pure shear component gradually increased with deformation. Analyses of the shear type and the three-dimensional deformation demonstrate that the QDSZ belongs to a lengthening-broadening shear zone with the lengthening quite obvious along the Y-axis. This means that ductile shearing played a role of crust-thickening during the cratonization at the end of Archean.

关 键 词：运动学涡度 剪切作用类型 三维变形 青邑韧性剪切带 韧性剪切带 剪切作用 类型 鲁西 糜棱岩化 前寒武纪基底 

分 类 号：P542[天文地球—构造地质学] P618.51[天文地球—地质学]