关键词: 砂箱实验, 冲断楔形体, 叠加冲起构造, 单一冲起构造

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.

Key words: sandbox modeling, wedge thrust, superimposed pop-up structure, simple pop-up structure