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

Abstract. Inversion of an extensional domino-like basement faults system with a pre-extension decoupling layer is presented as a set of analogue models to understand the role of pre-existing structural features during inversion. The present study expands the experimental program by Ferrer et al. (2022a) in which, models were carried out with different salt and overburden thicknesses to investigate the role played by the salt and by the overburden during extension but also, how extensional structures and salt distribution condition the evolution during inversion. The results show that after total inversion of the models, the resultant structural style of deformation is highly influenced by the inherited extensional configuration and by the thickness of salt which they both condition the degree of coupling/decupling between the pre- and syn-kinematic successions. While models with thick salt can partially or totally preserve the extensional ramp-syncline basin geometry independently of the overburden thickness, models with thin salt result in a total inversion of the ramp-syncline basins with the development of crestal collapse grabens and extensional faults affecting the overburden. Compression triggered the development or reactivation of salt-related structures such as primary weld reactivations (i.e., reopening and/or obliteration), diapir rejuvenation, salt thickening, thrust emplacement, etc. The development of these elements is conditioned by the salt thickness distribution at the end of the extension and therefore, a precise understanding of inherited salt-related structures in needed so to understand the inversion of the basin as well as characterise the structural style.