Three-dimensional geometry and displacement configuration of a fault array froma raft system, Lower Congo Basin, Offshore Angola: implications for the Neogene turbidite play

Abstract

Abstract We investigate fault growth and linkage during development of a rafted terrain in the Lower Congo Basin, offshore Angola. Miocene thin-skinned extension has led to the development of isolated raft blocks separated by a graben filled with syn-deformational strata. Angular unconformities together with thinning and onlapping of intra-raft strata onto salt bodies suggest that thick salt was mobile during thin-skinned extension. 3D fault array geometries and displacement patterns record the subsequent deformation history of the graben during further thin-skinned extension. The mode of thin-skinned extension has important consequences for the Neogene turbidite hydrocarbon play associated with the rafted province of the Lower Congo Basin. The presence of thick mobile salt will influence pre-salt source rock maturation and the development of pre-salt/post-salt hydrocarbon migration windows. Supplementary material: A movie of a 3D depth-converted fault model of the study area depicting the three-dimensional geometries of faulting associated with deformation of a cover sequence above a raft system is available at https://doi.org/10.6084/m9.figshare.c.4784598