川西北地区构造演化阶段及岩相古地理

The tectonics evolution and lithofacies palaeogeography in the northwest of the Sichuan Basin

通过野外调研、钻井岩心和物探资料,编制川西北地区各地质历史时期岩相古地理图,研究川西北地区地层沉积特征,对比龙门山构造带与米仓山构造带演化阶段不同特点.结果表明:由于勉略洋的开合,导致西段龙门山及北段米仓山的构造演化存在差异,可划分为6个主要阶段,依次是基底形成阶段、被动大陆边缘发育阶段、川西大陆边缘持续发育与川北勉略洋打开-俯冲阶段、陆陆碰撞造山与周缘前陆盆地演化阶段、陆内拗陷盆地发育阶段、川西南再生前陆盆地发育阶段.

Based on the data of field observation,drilling,seismic data and the research of predecessors,the characteristics of stratigraphy and the differences in the tectonic evolution stages between Longmenshan fault thrust belt and Micangshan fault thrust belt are studied.The existence of Mianlue Ocean during the Indo-Chinese epoch causes the differences of the evolution between the Longmenshan fault thrust belt and Micangshan fault thrust belt.We mapped the lithofaces palaeogeography of each period in the northwest of Sichuan Basin and divided the tectonic evolution into six major stages which serve as the basis of formation,the passive continental margins development,the continental margins development continuously in the west of Sichuan basin with the Mianlue Ocean development in the north,the continental collision and the peripheral foreland basin formation,intracontinental depression stage and the intracontinental reworking foreland basin of southwest of Sichuan basin.