青藏高原东缘晚中-新生代龙门山前陆盆地结构-建造特征研究

There is an intracontinental mountain-basin system in the eastern Tibetan Plateau, which is composed of Longmenshan fold-and-thrust belt and its foreland basin. It may be served as a natural laboratory to decipher the evolution and eastward growth of the eastern Tibetan Plateau. Based on analysis of kinematic vorticity, double- and triple-dating detrital thermochronology etc., we can reconstruct the Late-Mesozoic to Cenozoic structural framework, thrusting and uplifting processes and their coupling relationships to foreland sedimentation across the Longmenshan mountain-basin system. Furthermore combined with sandbox modeling, the mountain building processes of Longmenshan fold-and-thrust belt and its foreland basin, as well as the geodynamics may systematically be disclosed. These results could not only be significantly helpful for understanding of the geodynamics of the eastern Tibetan Plateau, but also provide useful data for oil/gas exploration in the Sichuan basin.

青藏高原东缘龙门山褶皱冲断带-前陆盆地系统既是我国西部中-新生代冲断构造和陆内前陆盆地的典型代表，也是探索高原东向生长及其动力学机制的天然实验室。本项目拟在详细的野外地质调查与测量、地震-测井剖面解释等基础上，以构造解析、碎屑岩年代学和砂箱物理模型等为主要方法手段，通过龙门山冲断带-前陆盆地系统结构-构造和运动学涡度研究，再现其结构-构造量化模型及晚中-新生代变形过程；通过前陆盆地不同结构带露头剖面连续样品多法（双法“Double dating”或三法“Triple dating”）碎屑岩年代学研究探讨龙门山冲断剥蚀-沉积建造耦合关系及其不同生长建造模式；进一步结合前陆盆地动力学砂箱构造物理模拟，揭示龙门山晚中-新生代前陆盆地结构-构造-剥蚀-沉积建造过程和机制。研究成果将大大促进我们对青藏高原东缘中-新生代崛起和生长动力学模式的理解，并可为探索四川盆地油气成藏及分布规律提供科学依据。

龙门山冲断带-川西前陆盆地系统地处青藏高原东缘，不仅是研究大陆碰撞构造的天然实验室，也是开展当代构造-剥蚀-沉积和地貌间动态反馈过程研究的理想场所。本项目通过龙门山山前带飞来峰群构造特征解析和多法年代学定年系统揭示龙门山飞来峰印支期-燕山期左旋走滑逆冲推覆与新生代快速抬升剥露成因过程；基于扬子板块西缘晚白垩纪-新生代连续沉积地层沉积学、重矿物和碎屑岩多法年代学分析，重建晚白垩世扬子板块西缘前陆盆地古地理特征；进一步结合砂箱物理模型模拟揭示出印支期以来沿龙门山冲断带走向变化的构造剥蚀-沉积作用过程对前陆盆地结构构造的控制影响作用，研究成果对青藏高原东缘隆升与生长机制、四川大型叠合盆地动力学与油气成藏动力学具有重要的参考价值。