Tectono‐sedimentary development of early syn‐rift deposits: the Abura Graben, Suez Rift, Egypt

摘要: The thickness and distribution of early syn-rift deposits record the evolution structures accommodating earliest phases continental extension. However, our understanding detailed tectono-sedimentary these is poor, because in subsurface, they are often deeply buried below seismic resolution sparsely sampled by borehole data. Furthermore, typically poorly exposed field, being beneath thick, late post-rift deposits. To improve development strata during initial stages rifting, we examined quasi-3D exposures Abura Graben, Suez Rift, Egypt. During stage extension, forced folding above blind normal fault segments, rather than half-graben formation adjacent to surface-breaking faults, controlled rift physiography, accommodation stratigraphic architecture non-marine, Fluvial systems incised into underlying pre-rift were structurally focused axis embryonic depocentre, which, at this time, was characterized a fold-bound syncline fault-bound half graben. phase sediment sourced from shoulder some 3 km NE crests flanking, intra-basin extensional folds. Fault-driven subsidence, perhaps augmented eustatic sea-level rise, resulted basin deepening deposition series fluvial-dominated mouth bars, like preceding fluvial systems, pinned within growing which still bound folds faults. eventually locally breached resulting establishment graben, shallow marine sandstone fan-delta conglomerates. Because growth faulting coeval along-strike, stratal units deposited time show highly variable along-strike architecture, thinning towards fold but, only few kilometres thickening fault. Despite displaying classic motif recording net upward-deepening, surface played key role controlling development, facies This structural observations required make interpretation relatively subtle may go unrecognized low-resolution subsurface data sets.