青藏高原东缘大凉山构造隆升及四川盆地的最终封闭

项目名称： 青藏高原东缘大凉山构造隆升及四川盆地的最终封闭

项目编号： No.41472107

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 李智武

作者单位： 成都理工大学

项目金额： 90万元

中文摘要： 四川盆地西南缘及其南侧的大凉山构造带位于特提斯-喜马拉雅构造域和滨太平洋构造域的交接转换部位，其形成演化对于理解西太平洋俯冲背景下中国南方大陆构造和青藏高原东缘构造具有重要意义。本项目拟在四川盆地西南部和西昌盆地白垩系-古近系剖面的细致测量基础上，通过碎屑组分、碎屑锆石U-Pb年龄和Hf同位素、泥质岩沉积地球化学指标等的精细对比，结合沉积相、不整合面、古流向等的分析，明确限定四川盆地由大型敞流盆地最终演变为封闭性内陆湖盆的时间；通过横穿四川盆地西南缘的构造剖面测制和构造解析，查明其构造几何学-运动学特征、构造叠加关系和构造期次等，再现其构造变形过程，进而探讨其形成和隆起方式；通过短距离、大高程差地表剖面样品的多重热年代学测试和热史模拟，恢复四川盆地西南边框的隆升-剥露历史和机制，最终恢复四川盆地西南缘盆山边界构建的地质过程，为整体把握四川盆地构造格局和完整认识其形成演化过程提供关键约束。

中文关键词： 青藏高原东缘；四川盆地；变形；隆升；沉积记录

英文摘要： The Daliang Shan tectonic belt and adjacent southwestern Sichuan basin are located at the transition zone between the West Pacific and the Tethys-Himalaya tectonic domains, and thus a key to decipher the continental tectonics of the South China Block since the late Mesozoic and the eastward growth of the Tibetan Plateau during the Cenozoic. Methods and techniques involved in this study comprise dis- and un-conformities investigation, facies and paleo-current analyses, clastic composition analysis of sandstones, element and isotope geochemistry of fine-grain sediments, zircon U-Pb dating, Ar-Ar dating, fission track and (U-Th)/He dating. Based on the Cretaceous to Plaeogene sedimentary records within the southwestern Sichuan basin and Xichang basin, structural analysis and multiple thermochronologic study, we may reconstruct systematically the deformation history and exhumation process of the Daliang Shan tectonic belt and the eventual closure of paleo-Sichuan basin from an endorheic basin to an exorheic basin. Research results will give crucial constrains on both the origin and development of the southwestern basin-mountain margin of Sichuan basin, which would not only better our understanding of the tectonic framework and evolution of Sichuan basin as a whole, but also enhance out knowledge of both the continental tectonics of the the South China Block in the setting of westward subdution of the Pacific Plade and the tectonic evolution of eastern plateau margin.

英文关键词： Eastern Tibetan Plateau margin;Sichuan basin;Deformation;Uplift;Sedimentary record