白云鄂博矿区北部韧性剪切带特征及其构造意义  

Characteristics of Ductile Shear Zone in the Northern Bayan Obo Ore Deposits, North China,and Its Structural Significance

作　　者：王俊[1] 吕洪波[1] 章雨旭[2] 柳建勇 李旭平[4] 黄敏[2] 孟庆伟[2] 

机构地区：[1]中国石油大学地球科学系,山东青岛266555 [2]中国地质科学院地质研究所,北京100037 [3]包钢矿业有限责任公司资源开发部,内蒙古包头014010 [4]山东科技大学地质科学与工程学院,山东青岛266510

出　　处：《地质学报》2012年第5期785-792,共8页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号41072074);包头钢铁公司研究课题"白云鄂博铁矿深部找矿项目"资助成果

摘　　要：在白云鄂博主矿北西约6.5km处的查干楚鲁一带,有一条近东西向延伸的断层带,前人在该带中部识别出了蛇绿岩混杂堆积。本文作者在蛇绿岩东部的大理岩质糜棱岩中发现鞘褶皱、拉伸线理及旋转碎斑系等变形构造,在大理岩周围发现石英岩型宏观压力影构造,在变质石英砂岩中识别出褶劈理以及方解石脉等相关构造,在这条东西向断裂带北边发现典型的黄铁矿型压力影。根据上述特征判断,查干楚鲁一带为一条近东西向延伸的韧性剪切带,同时具有NEE—SWW向逆左旋走滑的特征。该带揭示出蒙古洋板块与华北板块在晚古生代汇聚拼合的基本格局。An east-west-trending ductile shear zone was found in Chaganchulu,about 6.5 km north of the main ore of Bayan Obo Fe-Nb-REE deposit,Inner Mongolia,North China.Previous researchers just found an ophiolite m lange along the broad W-E trending valley.The authors of this paper discovered a series of ductile deformation structures at a mylonitic marble hill in the east of the zone.The ductile deformations include stretching lineations,sheath folds and rotated porphyroclasts,etc.Some crenulation cleavages and deformed calcite veins were also observed in the metamorphic quartz sandstone.Abundant macro pressure shadow structures are visible around quartzite.Meanwhile,pyrite-type pressure shadow was also recognized in the north of the belt.Judged from the above-mentioned characteristics,the Chaganchulu region is an east-west-trending ductile shear belt characterized by NEE—SWW sinistral strike-slip thrust.These indicate the preliminary pattern fact that the zone formed from convergence between the fossil Mongolian Ocean and the North China Plate in the Late Paleozoic time.

关 键 词：白云鄂博 韧性剪切带 蛇绿混杂岩 逆左旋走滑 

分 类 号：P542[天文地球—构造地质学]