Scientific Drilling ICDP Publications

The Cretaceous deposits in the Persian Gulf area are part of one of the largest hydrocarbon systems in the world. The stratigraphic evolution of the northern part of the Gulf is, however, poorly constrained. Seismic data from offshore Iran reveal that the shallow water deposition is marked by topographic features like the NNE-SSW trending Qatar-Fars-Arch and salt-related structures (diapirs and salt walls) of smaller scale. These structures were active during the Cretaceous. To examine the effect of salt-induced palaeobathymetric changes on carbonate deposition our study focus is the Albian-Turonian Sarvak Formation. An integration of seismic attributes within unconformity-bound packages has revealed subtle changes of depositional units and geometrical patterns. The reconstructed stratigraphic evolution reflects the interplay between sea-level changes and syn-sedimentary salt diapirism. During low sea-levels, high-relief areas were exposed and only deeper parts accumulated sediments. Rising sea levels lead to onlap of new deposits on the topographic highs, where sedimentation occurred only during highstands. In the study area salt tectonics of the Infracambrian Hormuz unit is pronounced. Localized salt diapirism within the Sarvak Fm. generated restricted topographic highs, with adjacent low areas subsiding due to corresponding withdrawal of rock salt layers. These locations are particularly prone to develop prograding carbonate bodies during forced regressions.

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Baaske, U. P.; Mutti, M.; Baioni, F.; Buonaguro, R.; Bertozzi, G.; Naini, M. A.; Krawczyk, C. M. (2004): Carbonate deposition and salt diapirism during the Cretaceous in the Persian Gulf, offshore Iran. Sediment 2004 (Aachen 2004).