Tectonic Controls on the Stratigraphic Architecture of the Permo-Triassic Khuff Formation, Eastern Saudi Arabia
M.O. Al Sheikh1, M. Al Marhoon1, M.H. Khalil1, and D.Z. Tang1
The Permo-Triassic Khuff Formation was deposited on a broad, low-relief carbonate platform trending northwest-southeast on the passive margin of the Neo-Tethys Ocean. This paper describes the stratigraphic architectures of the Khuff carbonates and the controls on its distribution in Eastern Saudi Arabia. Well data, seismic interpretations, and potential field geophysical data have been integrated to complete this study. The Permo-Triassic section in Eastern Saudi Arabia was bordered by the Arabian basement-shield to the west, Hail Arch in the north and the Hadramawt-Sana’a Arch in the south. The region was situated in low to moderate southern latitudes in an intra-cratonic setting, where shallow and warm water conditions prevailed during the Early Permo-Triassic to Lower Cretaceous times. The Arabian plate was a passive margin and is composed of multi-terrain basement fabric, in which it has undergone differential tectonic subsidence that resulted in numerous sub-basins. There are three global geological events of great significance at the Permian-Triassic time: the largest mass extinction, the long-term dominance of superanoxia, and the earliest breakup of Pangea. During transgressive phases, muddy facies were deposited mostly at sub-basins (paleo-lows), whereas carbonate buildups and grainier facies (reservoir) were deposited on the intervening paleotopgraphic highs. Thickness maps and regional composite cross section traverses across the region constructed from seismic and calibrated with well data indicate thickness variations corresponding to irregular basin topography resulted from differential subsidence of heterogeneous basement architectures. The Early Khuff clastics is interpreted to be deposited over a low strain rifted basin as indicated from horsts, grabens and tilted normal fault blocks in flattened seismic section at top Khuff. This rift evolved rapidly into passive margin. Exploration concepts are being generated as a result of the understanding of the controls on depositional and stratigraphic controls of the Khuff Formation.
AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain