الفهرس 
Sequence Stratigraphy and Architecture Of Syn-Rift Sediments, Eastern Margin of the Gulf of Suez, Egypt
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Abstract
This study aims to tackle some unfathomed issues in syn-rift sequence
stratigraphy and tectono-sedimentology. These are (i) figuring out how does the
growth of rift-margin structures interact with sediment influx and eustatic sealevel changes to control the syn-rift sequence architecture, (ii) investigating the
syn-rift sedimentary response to growth folding along a rift-margin transfer
zone, and (iii) improving the understanding and prediction of early syn-rift
deposition during early stages of structural deformation. To tackle these aims, a
detailed field mapping of key stratal surfaces and structures, litho- and biofacies
analyses were integrated with geochronologic data from biostratigraphy,
strontium and oxygen isotopes.
Eighteen key stratal surfaces of onlap, offlap and downlap were mapped within
six 3rd order early Miocene syn-rift depositional sequences. The tectonosedimentary analysis revealed that vertical and lateral propagation of the basin
bounding fault led to (i) development of a transfer zone at the fault tip which
acted as the main sediment fairway for fan deltas entering the basin, and (ii)
created a growth syncline in the hangingwall where coeval strata exhibit onlap
and thinning landward and divergence basinward. Toward the fault center,
subsidence was episodic and outpaced both eustatic falls and sediment influx
leading to a predominance of retrogradational systems tracts (60-85 % of the
sequences’ thickness). In contrast, at the transfer zone, sediment influx
overwhelmed the developed accommodation, and resulted in prograditional to
aggraditional systems tracts. Subtle eustatic sea-level change during the early
Miocene was mostly masked by the tectonic subsidence and sediment influx.
However, isotopic data reveals that eustatic falls contributed to the development
of some sequence boundaries during tectonic quiescence stages and uplifting of
an intrabasinal high.
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This study reveals also that rift-climax deposits associated with transfer zone
growth monoclines are mainly sourced from a hinterland drainage catchment
rather than local footwall scarps. The deposits form progressively tilted clastic
wedges that onlap and pinch out up-dip toward the growth monocline. Such
facies geometry is unlike those observed at faulted margins where the facies
commonly thicken toward the fault.