Geometry and kinematics of the Middle to Late Miocene salt tectonics, central Egyptian Red Sea margin

Abstract

The Red Sea basin includes a thick Middle to Late Miocene evaporitic succession that underwent halokinesis and caused intensive reshaping of the seafloor and the development of salt-tectonic structures. However, the geometry and kinematics of these structures are still poorly understood. This study uses 2D and 3D seismic surveys and well data of the northern Egyptian Red Sea to systematically describe the distribution and morphology of salt structures, discuss their initiation, and construct a kinematic model for their origin. Our results indicate that the massive salt layer developed into five major NW-SE to NNE-SSW trending salt walls, characterized by relatively irregular crests and moderately dipping flanks. In addition, several symmetrical and asymmetrical folds and two categories of normal faults (subsalt and suprasalt) have been recognized. Based on our observations, salt mobilization in the study area started in the Late Miocene, during the precipitation of layered evaporites, and continued until the present day. In the northern Egyptian Red Sea, seismic interpretation indicates that halokinesis was triggered by a combination of thin- and thick-skinned systems, where the latter played a major role. The salt layer was welded during the Quaternary as several sags and grabens developed above the salt diapirs. Thick-skinned physical models are compatible with our observations, supporting the impact of basement faulting on Red Sea diapirism.