西藏冈底斯构造带中段多岛弧-盆系及其演化

The multiple island arc-basin systems and their evolution in the Gangdise tectonic belt,Xizang

夹于班公湖 怒江和雅鲁藏布江两条巨型板块结合带之间的冈底斯构造带 ,并不是一个简单的陆块 ,而是一个经历有晚古生代—中生代复杂的多岛弧 盆系演化历史 ,可以划分出多个次级地质构造单元的碰撞造山带。自晚古生代以来 ,冈底斯构造带经历了从洋 陆转换 (D—T2 ) ,盆 山转换 (T3—K)和壳 幔转换 (E—Q)三次构造体制的转换及复杂的演化历史。班公湖 怒江板块结合带是特提斯大洋消减、碰撞闭合的主缝合带 ,雅鲁藏布江洋盆则代表了特提斯大洋南侧的弧后扩张小洋盆。

The Gangdise tectonic belt intermediate between the Bangong Nujiang and Yarlung Zangbo suture zones is not a simple continental mass; it has displayed a long and complex evolution of multiple island arc basin systems since the Late Palaeozoic, i.e. ocean continent transition during the Devonian to Middle Triassic, basin range transition during the Late Triassic to Cretaceous and crust mantle transition during the Paleogene to Quaternary. The tectonic zone may be divided into ten secondary tectonic units from north to south: ⑴ Nyainrong Late Palaeozoic Mesozoic residual magmatic arc; ⑵ Guiya Yilashan Xagquka arc arc collision suture zone; ⑶ Nagqu backarc basin; ⑷ Baingoin Lhari Jurassic Cretaceous residual magmatic arc; ⑸ Yunzhug Zangbo Nichang arc arc collision suture zone; ⑹ Xainza Palaeozoic carbonate platform; ⑺ Gyaringco Namco Gyuzela Jurassic arc arc collision suture zone; ⑻ Coqen Nyainqentanglha Early Permian Mesozoic island chain zone; ⑼ Milashan Songduo arc arc collision suture zone; ⑽ South Gangdise Mesozoic Cenozoic volcanic magmatic arc. The Bangong Nujiang suture zone is interpreted as a major suture zone created by the subduction and collision of the Tethys Sea, and the Yarlung Zangbo oceanic basin represents the small backarc oceanic basin in the southern part of the Tethys Sea.