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位于青藏高原东缘的龙门山前陆盆地是中国典型的前陆盆地之一。自晚三叠世以来,该盆地充填了厚度大于1万余米的海相至陆相沉积物,以不整合面为界可将其划分为6个构造层序,根据几何形态将构造层序区分为两种类型,即楔状构造层序和板状构造层序,其中晚三叠世、晚侏罗世、晚白垩世—古近纪构造层序为楔状构造层序,其余为板状构造层序。研究结果表明楔状构造层序为逆冲构造负载的产物,板状构造层序为走滑剥蚀卸载的产物。本次以晚三叠世前陆盆地为典型的楔状前陆盆地开展了逆冲构造负载系统的弹性挠曲动力学模拟,以晚新生代龙门山前陆盆地为典型的板状前陆盆地开展了与走滑剥蚀卸载系统的弹性挠曲动力学模拟,并计算了龙门山构造负载系统向扬子克拉通的推进速率,结果表明龙门山造山楔的推进速率在早期较快(如晚三叠世最大推进速率达15mm/a),晚期较慢(如晚侏罗世、晚白垩世—古近纪最大推进速率仅为6.7mm/a)。进而推测龙门山幕式逆冲作用的构造驱动力来自于青藏高原中生代以来的基麦里大陆加积碰撞和印度与亚洲板块碰撞作用,其中晚三叠世楔状构造层序是羌塘板块与亚洲大陆碰撞的产物,晚侏罗世楔状构造层序是拉萨板块与亚洲大陆碰撞的产物,晚白垩世—古近纪楔状构造层序是科希斯坦板块、印度板块与亚洲大陆碰撞的产物。
The Longmenshan foreland basin on the eastern edge of the Qinghai-Tibet Plateau is one of the typical foreland basins in China. Since the Late Triassic, the basin has been filled with marine-to-continental sediments more than 10,000 m thick. Dividing unconformities into six tectonic sequences, the basin is divided into structural sequences There are two types, ie, wedge-shaped structural sequence and plate-shaped structural sequence. Late Triassic, Late Jurassic and Late Cretaceous-Paleogene structural sequences are wedge-shaped structural sequences and the rest are plate-like structures Sequence. The results show that the wedge-shaped tectonic sequence is the product of the thrust load, and the plate-like tectonic sequence is the product of the strike-slip erosion unloading. This time, the Late Triassic foreland basin is a typical wedge-shaped foreland basin. The flexural-flexural dynamic simulation of the thrust load system is carried out in the Late Pleistocene Longmen Shan foreland basin as a typical plate-shaped foreland basin The results show that the advancing rate of Longmen Shan orogenic wedge is faster at early stage (such as late Triassic The maximum advancing rate is up to 15 mm / a), while the late ones are slower (eg, the Late Jurassic and Late Cretaceous - the maximum propulsion rate of the Paleogene was only 6.7 mm / a). Furthermore, it is inferred that the tectonic driving force of the Longmenshan episode thrust came from the collisional collision of the Kameri continent with the Mesozoic in the Tibetan Plateau and the collision between India and the Asian Plate. The Late Triassic wedge-shaped structural sequence is that Qiangtang Plate and Asia Continental collision products, the late Jurassic wedge-shaped tectonic sequence is the collision between the Lhasa plate and the Asian continent. The Late Cretaceous-Palaeogene wedge-shaped structural sequence is the product of collision between the Korschtan plate and the Indian plate and the Asian continent.