拉萨地块北部逆冲推覆构造系统  

Thrust System of the North Lhasa Block

作　　者：吴珍汉[1] 叶培盛[1] 胡道功[1] 刘琦胜[1] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081

出　　处：《地质论评》2003年第1期74-80,T005,共8页Geological Review

基　　金：国家重点基础研究发展规划(编号95-13-O1-06);西藏当雄幅1:25万区域地质调查项目与INDEPTH-Ⅲ五项目地质课题的成果。

摘　　要：拉萨地块北部发育大型逆冲推覆构造系统(NLT),由前锋纳木错构造带、根部安多—伦坡拉构造带和底部滑脱构造带所构成。前锋纳木错构造带总体呈WNW向展布,由20多条向北倾斜的逆掩断层、宽阔的韧性剪切带、4条蛇绿岩片带与大量不同类型的构造岩片所组成。根部安多—伦坡拉构造带位于班公—怒江缝合带中段,由3条WNW向一近EW向逆冲断裂带、宽阔的蛇绿混杂岩岩片与已发生褶皱的古近纪盆地所组成。底部为中上地壳滑脱带,对应于15～30km深处的高导层,主要由蛇绿岩和构造岩组成。NLT推覆距离达120～150km,主要形成时代为古近纪晚期—新近纪早期。Large-scale thrust system was discovered in North Lhasa Block, which is called the North Lhasa Thrust (NLT). It consists of the Nam Co tectonic belt as the front part, the Ando-Lunpola tectonic belt as the root part and the detachment layer at 15 - 30 km depth within the middle-upper crust as the lower part. The Nam Co tectonic belt of WNW-trending occurring in west of the Namco Lake is composed of 20 thrust faults of north dipping, wide ductile shear zone, 4 belts of ophiolite pieces and many thrusted rock pieces. The Ando-Lunpola tectonic belt located in middle of the Bangoin-Nujiang suture includes 3 thrust faults of WNW-trending, wide ophiolite complex and folded basins of the Early Tertiary. The lower part of the NLT, the detachment layer in middle-upper crust, is corresponding to the high-conductivity layer of crust at depth of 15 - 30 km and is comprised of ophiolite pieces and thrusted rock pieces. The southward thrusting of the NLT is about 120 -150 km, which mainly occurred in late Oligocene-early Miocene.

关 键 词：拉萨地块 逆冲推覆构造系统 逆掩断层 蛇绿混杂岩 深部滑脱带 

分 类 号：P542[天文地球—构造地质学]