青藏高原南羌塘地块中生代古地磁研究及其古地理意义

班公湖—怒江缝合带是青藏高原重要的地质界限之一，认识其所代表特提斯洋盆的构造演化过程具有重要的科学意义与实际价值。然而，班公湖-怒江特提斯洋盆规模及开合过程至今仍存争议。恢复其南北两侧块体（拉萨和南羌塘块体）中生代运动学过程是解决争议的路径之一。本项目针对现有工作的薄弱点，拟对南羌塘地块三叠-白垩纪沉积-火山岩序列开展系统的岩石矿物学、年代学和古地磁学研究，应用多种手段综合评价沉积岩磁记录中倾角浅化及火山岩磁记录中古长期变的影响，通过同位素年代学与古生物地层学，最终获得南羌塘地块具有精确年龄约束的中生代古纬度，完善该地块关键时间段的视极移曲线。结合拉萨块体已有同时代高质量古地磁数据，直接对比两块体间的纬度变化，进而对班公湖-怒江特提斯洋洋盆规模及开启闭合过程进行约束。

The Bangong-Nujiang suture zone is one of the important geological boundaries in the Tibet Plateau. The tectonic evolution process of the Bangong-Nujiang Tethys oceanic basin has important values in both science and economics. However, the scale and opening-closing process of this oceanic basin during the Mesozoic are still controversial. The Mesozoic kinematics of the blocks (southern Qiangtang and Lhasa blocks) on both sides of Bangong-Nujing suture are the key points to clarify this controversy. In this project, we will conduct systematic petrographic, chronological and paleomagnetic studies on the Triassic-Cretaceous sedimentary-volcanic rock sequences of the southern Qiangtang block, which is the weaknesses and key point in the finished studies. Comprehensively evaluate the potential influence in both sedimentary rock results affected by the inclination shallowing and volcanic rock results affected by the long-term secular change, the results of this work will obtain well-dated Mesozoic paleopoles of southern Qiangtang block through isotope chronology and palaeontology stratigraphy works. The results, in combination with high-quality paleomagnetic data from the Lhasa block, allow us to compare the latitude changes between the two blocks during the Mesozoic, and constrain the opening and closing process and scale of Bangong-Nujing Tethys oceanic basin further.