四川攀西裂谷的构造环境及构造发展

攀西的结晶基底岩系——康定群,褶皱基底岩系——会理群、昆阳群与北澳大利亚地区一致,是泛冈瓦纳大陆的组成部分。泥盆—二叠纪时期,扬予古陆发生强烈地裂运动,后期扬予古陆向北漂移,导致了它与澳大利亚的分裂,这时攀西不再是一个单纯的内陆裂谷,它发展为原大洋,成为扬予古陆西缘的被动大陆边缘裂谷。二叠纪末它可能与同步向北漂移的羌塘-印支古陆拼合:三叠纪初与华北陆块拼合;于侏罗纪、白垩纪分别与藏北及藏南陆块拼合;喜马拉雅运动,印度板块碰撞,形成了统一的亚洲大陆,本区受造山作用影响,形成广泛的冲断-推覆体构造形体。

TECTONIC ENVIRONMENT AND TECTONIC DEVELOPMENT OF PANXI RIFT IN SICHUAN

The crystalline basement ( Kangding Group ) and foldedbasement ( Huili Group and Kunyang Group ) in Panxi region are .correlated with strata in north Australia. Owing to a strong taphrogeny, Yangzi old land in Devonian-Permian drifted northwards resulting in separation of it from Australian continental block. It was a part of Pan-Gondwana land break-up .Thus, Pagxi region was no longer a simple continental rift. It developed into a proto-ocean. As a result of continuing drift of the Yangzi old land northwards, Panxi region became a passive continental margin rift in the western margin of the Yangzi old land. The collision of it with Qiangtang-Indo-China continental block was in the end of Permian, and the collision of it with North China continental block was in early Triassic. Finaly, the collision of North Tibet, South Tibet continental block and Indian plate with Asiatic land mass was in Jurassic and Cretaceus Tertiary and Panxi tectonic-magmatic complex zone formed.