Extensional Origin and Basement Control of the Marib Sub-Basin, Yemen: Evidence from 2D Seismic and Field Geological Data

The structural evolution and tectonic origins of the Marib Sub-basin, a major Mesozoic rift system within Yemen's Sab'atayn Basin, remain debated. This study aims to resolve this by reconstructing the basin’s structural architecture and determining the role of inherited Precambrian fabrics. We integrated detailed geological field observations with subsurface 2D seismic reflection data to map fault geometries. The structural analysis reveals an asymmetric, NW–SE-trending half-graben, where master boundary faults downthrow the crystalline basement by more than 2,800 m. This geometry was strongly controlled by inherited Precambrian basement fabrics, specifically the Najd Fault System and the boundary separating the Abbas Gneiss and Al-Bayda Island Arc terranes. Seismic interpretations demonstrate a two-tiered architecture: deep basement-rooted normal faults, and a shallow detached system of listric faults within the Sab'atayn evaporites. Crucially, positive flower structures are confined strictly to the northeastern sector within the syn-rift succession, representing localized transtensional adjustments rather than basin-scale strike-slip kinematics. We conclude that the Marib Sub-basin evolved as an extension-dominated intracontinental rift. This updated framework provides significant additive value by clarifying structural inheritance mechanisms, offering a refined blueprint for understanding similar structurally inherited rifts and optimizing hydrocarbon exploration across the southern Arabian Plate.