Morphological evidence for the extension of the Zabargad Transform Fault Zone to the Saudi Arabian Red Sea margin

Abstract

The fault locations and orientation of the Zabargad Transform Fault Zone, also called the Zabargad Fracture Zone (ZFZ), have previously only been delineated by satellite-based geophysical data, causing intense debate over the last few decades. Newly recognized geomorphological features identified in bathymetric and LiDAR data from the NE Red Sea margin present the first ground evidence for the northern extent of the ZFZ. The features are aligned over 84 km, starting from the Mabahiss Deep, near the spreading axis, and continuing to the shallow Saudi Arabian shelf along the northern termination of the Al Wajh carbonate platform. Analysis of the seafloor morphology reveals three geomorphic terrains: (1) a deeply incised canyon feeding into the Mabahiss Deep, which is characterized by dozens of amphitheatre-shaped scarps; (2) a 22 km wide head-scarp that follows the edge of the Al Wajh platform; and (3) multiple fault scars and graben-like structures on the shallow shelf. We interpret these morphological features as deformation indicators associated with the deformation processes in the ZFZ and postulate that they represent the northern end of the ZFZ. In addition, the fault zone delineates the NW margin of the Al Wajh carbonate platform and most likely continues to shape it. This paper gives new insights into the interaction between fracture zones and continental margins and their role in the morphogenesis of the seafloor.