前陆褶皱冲断带冲起构造发育特征:基于砂箱构造物理模拟实验研究
Pop-up Structure in Fold-and-thrust Belt and Its Implications: An Insight from Analogue Sandbox Models of Thrust Wedge

摘要： 冲起构造广泛发育于挤压逆冲构造体系和走滑构造体系，具有极其重要的油气勘探价值，因而备受关注。砂箱模拟模型已经被证明是强大的可视化工具，用来模拟不同岩层中复杂的构造现象。基于相似初始砂箱构造模型条件下不同挤压速率(0.3 mm/s、0.1 mm/s、0.005 mm/s)变形过程，揭示出褶皱冲断带发育过程中的典型两类冲起构造：叠加冲起构造和单一冲起构造，它们对于褶皱冲断带演化过程及其油气勘探具有明显不同的重要性。砂箱物理模拟实验揭示楔形体扩展变形序列对前陆褶皱冲断带冲起构造发育类别具有重要控制作用，即褶皱冲断带前缘以前展式扩展变形为主，主要发育单一冲起构造；后缘以后展式扩展变形为主,主要发育叠加冲起构造。
Abstract: Pop-up structure is widely developed in fold-and-thrust belt and strike-slip tectonic setting, and has been paid much attention for its great significance in petroleum exploration. Analogue sandbox modeling has proved to be a powerful visual tool for simulating such complex structures in various tectonic settings. This study conducted a series of sandbox modeling to unravel the difference in structural geometry of pop-up structure during the development of fold-and-thrust belt, based on the same initial condition with various shortening velocities (0.3 mm/s, 0.1 mm/s, 0.005 mm/s). From the modeling results, two types of pop-up structures, i.e. superimposed and simple pop-up structures, would be developed in thrust wedge depending on different shortening velocities. In particular, there is a significant difference between superimposed structure and simple pop-up structure. The wedge shows simple deformation styles characterized by simple pop-up structures and increasing deformation while propagating continuously towards foreland. The propagation way of analogue sandbox models of thrust wedge has a significant control on the types of pop-up structure. Forward-breaking propagation took place in the foreland, mainly developed from simple pop-up structure; back-breaking propagation occurs in hinderland, mainly developed from superimposed pop-up structure