Geological Behavior (GBR)

This study investigates the tectono-stratigraphic response of the continental red beds of Abu Zenima Formation, Sinai using digital outcrop modelling to the evolution of the intra-block Nukhul fault zone during the Oligo-Miocene initial rifting phase in the Suez Rift, Egypt. Nukhul fault zone is one of the several intra-block fault zones from a 500 Km2 area of the Hammam Faraun fault block and is interpreted to have evolved from two isolated fault segments trending NW-SE. Abu Zenima Formation represents the early fluvio-lacustrine syn-rift stratigraphy and documents an early phase of basin fill in the hanging-wall of Nukhul fault zone. The stratal geometries are characterised by considerable along-strike variability in thickness and onlap relationship. The thickest stratigraphy developed towards the centre of the fault segments. This shows variation in displacement along the strike from maxima at fault centre to minima at fault tip produced as a result of temporal and spatial evolution of normal fault growth. Fault-propagation folds that form due to the growth of extensional faults, in particular fault-parallel syncline and fault-perpendicular anticline control the structural style of the early syn-rift basin. The observed onlap relationship of the lower stratal geometries and the subsequent pronounced thinning of the upper stratal geometries towards the fault-perpendicular anticline from the two NW-SE segments, indicates that the two fault segments interacted at an early age during the initial rifting and were subsequently linked as a normal fault zone. The implication of this study could be related to hydrocarbon exploration of early syn-rift play in many rift basin within the passive (Atlantic type) continental margins. Such basin contains excellent fluvial reservoirs with thickness variation, truncation and onlap relationship across the basin. Thus, understanding the tectonic control and other synorogenic sedimentation and resultant depositional geometries of syn-rift sedimentary rocks will substantially reduces hydrocarbon exploration risk.