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

Abstract

Fault locations and orientation of the Zabargad Transform Fault Zone, also called the Zabargad Fracture Zone (ZFZ) have, so far, only been delineated by satellite-based geophysical data, causing intense debate over the last decades. Newly recognized geomorphological features identified in bathymetry 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 continue to the shallow Saudi Arabian shelf, along the northern termination of the Al Wajh carbonate platform. Analysis of the seafloor morphology revealed three geomorphic terrains: (1) a deep 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 Al Wajh platform edge, (3) and multiple fault scars and graben-like structures on the shallow shelf. We interpret these morphological features as deformation indicators in association 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 northwest margin of the Al Wajh carbonate platform, and most likely continues to shape it. This paper gives new insights in the interaction between fracture zones and continental margins and their role in the seafloor morphogenesis.