Does the syn- versus post-rift thickness ratio have an impact on the inversion-related structural style?

Abstract. Many extensional basins worldwide are modified by subsequent compressional episodes, which lead to inverted structures. The structures associated with the reactivation of preexisting faults play are critically important in forming suitable subsurface traps for hydrocarbons. Major concerns regarding inverted structures are trap integrity and fault seal. In general, the preferred structures have simple four-way closures as the result of only mild to moderate inversion.

Five physical sandbox models, coupled with Particle Image Velocimetry (PIV) analysis, have been performed to address the influence of the syn- versus post-rift thickness ratio (Mode I and II) and the degree of positive inversion on the style of fault propagation into and overall deformation of the post-rift cover. The results of these experiments are broadly comparable with natural data examples from New Zealand, Israel and Turkey. The main control on the development of mild to moderate inversion structures is the degree of inversion, and the style of deformation within the post-rift sequence appears to be different due to the amount of displacement accommodated by the inherited listric fault and the thickness of the post-rift cover (Mode I and II inverted structures). These observations do have a direct impact on the understanding of the geo-energy systems associated with inverted structures.