滇西泥盆纪——三叠纪盆—山转换过程与特提斯构造演化

滇西地区以昌宁－连缝合带为古特提斯主洋闭合的位置。晚古生代－中生代时期古特提斯经历了一次盆转山和山控盆演变序列的全过程，可大致划分为4个发展阶段：（1）洋盆扩张阶段（D－C2）。古特提斯洋西侧的保山地块属冈瓦纳古陆的东缘，为非火山型被动大陆边缘；东侧的思茅地块属扬子地块的西缘部分，为火山型被动大陆边缘。（2）洋－陆汇阶段（C3－P2）。昌宁－孟连洋向东俯冲消减，思茅地区转化为弧后扩张盆地；墨江一带形成弧后扩张洋盆，思茅地块从扬子西缘分离。（3）弧－陆碰撞阶段（T1－T3），古特提斯主洋及分支洋盆相继关闭，全区发生大规模的造山升隆，前期的盆转山过程转入山控盆阶段，在哀牢山两侧分别形成了受造山作用控制的兰坪－思茅弧后前陆盆地和楚雄周缘前陆盆地。（4）陆－陆碰撞阶段（J1－K），滇西前陆盆地向陆内拗陷盆地转变，造山带的控盆作用结束。

DEVONIAN-TRIASSIC BASIN-RANGE TRANSFORMATION AND THE TECTONIC EVOLUTION OF PALEO-TETHYS IN WESTERN YUNNAN, CHINA

Changning Menglian suture zone represents the closure of Paleo Tethys main ocean. During the late Paleozoic to Mesozoic, Paleo Tethys experienced the processes of basin to range transformation and then of orogenic belt controlled basin formation.The processes can be divided into four stages: (1) Ocean expending stage (D C 2):Baoshan block in the west of Paleo Tethys ocean, belonged to the eastern margin of Gandwana land and was the passive continental margin of non magma type. Simao block in the east of Paleo Tethys, belonged to the western margin of Yangtze continental block and was the passive continental margin of magma type. (2) Ocean continental convergence stage (C 3-P 2):Changning Menglian ocean crust was subducted eastward, as result, Simao block transformed from passive continental margin into rear arc extending basin, bringing about the formation of Mojiang rear arc ocean and the separation of Simao block from Yangtze continental block. (3) Continental island arc collision stage (T 1-T 3):Changning Menglian ocean and Mojiang ocean closed successively, which caused large scale uplifting in the west of Yunnan,and the evolution came to the stage of orogenic belt controlled basin. Lanping Simao rear arc foreland basin and Chuxiong peripheral foreland basin were formed respectively in both sides of Ailaoshan orogenic belt. (4) The continental collision stage (J 1-K):The foreland basins of the western Yunnan was transformed into intercontinental down warped basins. The process of orogenic belt controlled basin formation finished.