中蒙边境地区特大型推覆构造带中的断层泥分析  

Analysis of Gouges in the Sino-Mongolian Boundary Thrust

作　　者：王玉芳[1] 郑亚东[1] 王新利 

机构地区：[1]北京大学地质学系

出　　处：《北京大学学报（自然科学版）》1995年第1期115-128,共14页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家自然科学基金

摘　　要：中蒙边境特大型推覆构造带中的断层泥厚约数厘米至数十厘米，局部厚达３ｍ，是一套未粘结的断层岩。断层带中的１３个断层泥样品分析表明，粘土矿物（粒径＜２μｍ）的含量变化范围较大，约占５％～４４％。这些粘土矿物主要是伊利石、高岭石，其次为蒙脱石和绿泥石，呈棱角状碎片和圆化的碎砾。研究发现了微量机械碾磨成因的粘土矿物显微球状砾。碎裂的伊利石不宜用于Ｋ－Ａｒ模式年龄测定。碎裂的粘土矿物及显微球状砾说明，所研究的推覆断层可能至少经历两次活动。断层泥中石英碎砾的溶蚀形貌以及自形石膏和方解石晶体表明该断层不是活断层。The faulted rocks in the Sino-Mongolian Boundary Thrust are uncohesive gouges commenly a few or tens of centimeters in thickness(locaily up to 3 meters)。Analysis of 13 gouge samples show that the content of clay minerals(grain size<20μm)are quite variable,ranging from 5 to 44 percent; The main clay minerals are illite and kaolinite; remaining clay material is montmorillonite and chlorite。 These clay minerals appear as either angular fragments or rounded granulitic grains。 Some micro-spheroclasts or microsphaeroidal fragments of clay minerals caused by mecha-nical grinding are found in the gouge。 The illite fragments are not suitable for K-Ar model age determination, The fragments of clay minerals and micro-spheroclasts sug-gest that the thrusting occurred at least twice, The morphological features on the quartz grains are due to solution;these grains along with euhedral crystals of gypsum and calcite imply that the thrusting is inactive。

关 键 词：推覆构造 断层泥 显微球状砾 构造地质学 

分 类 号：P542.3[天文地球—构造地质学]