Structural control of inherited salt structures during inversion of a domino basement-fault system from an analogue modelling approach

Abstract

The geometries of inverted rift systems are different depending on a large variety of factors that include, among others, the presence of decoupling layers, the thickness of the pre- and syn-extension successions, or structural inheritances. Our study focuses on the inversion of an extensional domino-style basement-fault system with a pre-extension salt layer using analogue models to understand the role of pre-existing structural features during inversion. Models investigate how different overburden and salt thicknesses, inherited extensional structures, and salt distributions condition the evolution during inversion. The experimental results show that models with thick salt can partially or totally preserve the extensional ramp-syncline basin geometry independently of the overburden thickness. In contrast, models with a thin salt layer result in a total inversion of the ramp-syncline basins with the development of crestal collapse grabens and extensional faults affecting the overburden. Inversion also triggered the growth or reactivation of salt-related structures such as primary weld reopening and/or obliteration, diapir rejuvenation, salt thickening, or thrust emplacement. The use of analogue modelling allowed us to address the processes that controlled the growth and evolution of these structural elements during the inversion. Experimental results also provide a template of different structural styles resulting from the positive inversion of basins with a pre-extensional salt layer that can help subsurface interpretation in areas with poor seismic imaging.