Jurassic evolution of the Arabian carbonate platform edge in the central Oman Mountains

Abstract : The Jurassic Sahtan Group exposed in northern Oman was deposited in shallow marine environments at the edge of the Arabian Platform facing the Neo-Tethys (Hamrat Duru Basin). The upper Sahtan Group is made up of a mixed siliciclastic–carbonate unit overlain by pure carbonate deposits, assigned to a Bathonian and Early Callovian age on the basis of brachiopods and foraminifers. These carbonate depositional systems were composed of outer oolitic shoals that underwent subaerial exposure, and a deeper, somewhat restricted, gently dipping shelf interior. Oolitic material was shed off the platform edge into the deep-sea depositional complex of the Guweyza Formation. The Sahtan Group is affected by an important thickness reduction towards northeastern Jabal Akhdar. The angular unconformity (0.2%) at the top of the Sahtan Group is shown to result from tilting and top truncation of genetic sequences. This unconformity is overlain by the Rayda Formation, a veneer that shows an onlap pattern including a gradual deepening upwards facies evolution. The minimal time span of the stratigraphic hiatus is Mid-Callovian–Kimmeridgian. Oxfordian and Kimmeridgian sequences were probably never deposited in this area because of lack of accommodation space and/or because of subaerial exposure. It is proposed herein that the unconformity was shaped by subaerial carbonate dissolution during a steady, tectonically driven exhumation of the platform edge. During the Tithonian, a major eustatic sea-level rise caused transgression of the Rayda Formation upon the platform edge and normal shelf marine conditions resumed in the eastern Arabian Peninsula.
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Submitted on : Tuesday, October 30, 2007 - 11:12:13 AM
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  • HAL Id : hal-00183682, version 1

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Mathieu Rousseau, Gilles Dromart, Jean-Pierre Garcia, François Atrops, François Guillocheau. Jurassic evolution of the Arabian carbonate platform edge in the central Oman Mountains. Journal of the Geological Society, London, 2005, 162, pp.349-362. 〈hal-00183682〉

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