The Primary Research Of Geological Characteristics Of Anduo Arc-structure In Tibet

Studying on the characteristic of geometry, kinematics and dynamics of different-scale structure according to structural analyses, this paper summarized the characteristic and the evolution of Anduo-arc-structure zone. The Anduo arc-structure fault zone, which is mainly composed of Wenquan-Benqu fault, 116Daoban-Baixiongbei fault and Sangqu-Baixiongnan fault from north to south, is a part of the Bang-Nu suture zone. The arc-structure fault zone is influenced by multi-period tectogeneses, which includes violent compression and extension. Since Neogene, the fault zone is always active. The later tectogenesis changed the former thrusting faults into normal faults, which forms the southern fault of the Anduo fault trough. All tectogeneses came into being the structural landscape of the Anduo arc-structure. Based on the research of geometry, kinematics, tectonite and the relationship of different structure traces, and the analyses of regional deposition, magmatism and evolution of the regional stress field, the paper concludes that since Mesozoic Anduo arc-structure zone came through four tectogeneses, which are: ⑴Compressive from late Jurassic to　early　Cretaceous; ⑵Extensive during early of late Cretaceous; ⑶Compressive from late Cretaceous to Paleogene; ⑷Extensive during Neogene.