Faulting intersections and magma-feeding zones in Tihamat-asir, Southeast red sea rift: Aeromagnetic and structural perspective

Abstract

The Tihamat-Asir area is located in southwest Saudi Arabia between the Asir Mountains and the Red Sea coast. Herein, the Tihamat-Asir area aeromagnetic data are re-interpreted to explain the magmatic activity and related structural interaction between extensional normal and transfer strike-slip faulting. The magnetic anomaly structural interpretation indicates that faulting and related magmatic activities are the main structural features affecting the study area. The magnetic signatures reveal oceanic crust underlying the onshore and offshore western side of the study area, while the eastern side is characterized by a broad, low magnetic anomaly indicative of continental crust. The boundary between the oceanic and continental crusts is not sharp, and represents a transitional zone, characterized by magnetic gradient steepness potentially related to mid-Cenozoic gabbroic plutons and volcanic flows together with normal faults injected by Cenozoic basalts. This zone incorporates three NW striking normal faulting and NE striking transfer strike-slip faulting system intersections, located close to Baysh, Abu Arish, and southwest of Abu Arish. The intersectional interactions between these two faulting systems have resulted in brittle magma-feeding zones that have allowed magma to reach the surface at these localities, and is believed to have resulted from the fracturing process affecting these localities due to the accumulated stress exerted by the movement of the NE strike-slip faults along the normal NW faulting systems and the associated releasing bends. A pull-apart magma-feeding zone is the structural model proposed to explain the interpreted brittle magma feeding zones and the associated magmatic activities in the study area.