西藏普兰、吉隆沟一带藏南拆离构造新认识

New explanation of detachment structures in the Burang and Gyironggou regions,southern Xizang

摘要: 西藏普兰、吉隆沟一带藏南拆离构造发育较为完整,主滑脱面位于基底聂拉木岩群与盖层肉切村群及绒沙组之间,但部分地段被中新世二长花岗岩侵蚀。调查研究认为,藏南拆离构造具有长期、多期活动性,不仅在中新世有多次强烈活动,而且在古生代至中生代长期伸展拉张作用过程中就已逐步形成并不断活动,至少在早石炭世、早二叠世、早三叠世、晚三叠世、早侏罗世等均有过较强烈至强烈的活动。

Abstract: The detachment structures are well developed in the Burang and Gyironggou regions, southern Xizang. The major decollement surface lies between the Nyalam Group Complex at the base and Rouqiecun Group and Rongsha Formation on the top. However local segments are occupied by the Miocene adamellite. These detachment structures have recorded multiphase tectonic activities during the Miocene and even from the Palaeozoic to the Mesozoic, especially during the Early Carboniferous, Early Permian, Early Triassic, Late Triassic and Early Jurassic.