Control of pre-existing faults on transtensional and transpressional fault systems: A perspective from analogue modelling

Structural superimposition has been broadly observed in petroliferous basins worldwide. Previous studies also realized the important control of pre-existing faults on subsequent fault systems developed in sedimentary covers. However, due to the high level of complexity in structural superimposition, it is difficult to reveal the detailed processes of fault architecture and evolution by seismic interpretation and backward structural restoration. In this research, the role of pre-existing faults in controlling resultant fault systems in multiple staged structural superimposition was investigated, from a perspective of physical analogue modelling. Both transtensional and transpressional faulting deformation were simulated by superimposing later tension and contraction at an angle of 60° to the pre-existing faults. The transtensional and transpressional fault systems were statistically analyzed by rose diagrams and stereonets, in terms of resultant faults' geometry, kinematic fault linkage and dynamics. Two natural examples from central Sichuan basin (southwest China) and north Anatolian (east Turkey) were then selected to make comparisons with our transtensional and transpressional analogue models, to investigate faults' spatial distribution, fault linkage patterns, dynamic evolution process, and mechanical mechanism of the transtensional and transpressional fault systems. The results of this study may provide some useful hints for understanding the fault architecture and fluid flow behavior in a basin that experienced multiple staged structural superimposition.