Print this pageInfluence of Fault Growth on Synrift Sediment Dispersal and Stratal Architecture: A Case Example from the Suez Rift
GUPTA, SANJEEV, JOHN UNDERHILL, IAN SHARP and ROB GAWTHORPE
The interaction between the growth of normal fault systems and synrift sedimentation is poorly understood. This is particularly true for sediment dispersal patterns, facies architecture and sequence stratigraphy of synrift successions. The aim of this study is to investigate how the vertical and lateral growth of rift-bounding fault segments has controlled the development of coarse-grained depositional systems in a Miocene marine half-graben on the eastern margin of the Gulf of Suez rift.
The Alaqa coarse-grained fan delta complex comprises a stacked set of early Miocene footwall-derived Gilbert-type fan deltas which are located in the immediate hangingwall of the rift border fault. The fan deltas grade basinwards and laterally into turbidites and basinal shales. Paleocurrent data indicate that the fan delta complex formed a point-sourced depositional system developed at the intersection of two rift-bounding extensional fault segments. Synrift on lap relations and growth strata geometries demonstrate that these structures developed as fault-propagation folds above upward and laterally propagating normal faults. Linkage of propagating fold/fault segments has resulted in the focusing of sediment dispersal to a point source.
Our results demonstrate that the 3D variability of synrift facies distributions, stratal architecture, and the position of sediment entry points is directly linked to the geometry of rift-bounding fault segments, and their pattern of growth and interaction. The study has implications for: (a) the search for subtle hangingwall stratigraphic/structural traps, (b) reservoir geometry of coarse clastic depositional systems developed adjacent to border fault segments, and (c) in the accurate prediction of sediment dispersal pathways.