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Stratigraphic Architecture of Two Cretaceous Carbonate Platforms: Gulf Coast and Arabia

R. W. Scott

The Comanchean shelf and the southeastern part of the Arabian platform shared similar types of biota and were located in similar climatic zones. However, their tectonic settings were different. The Comanchean shelf lay around the trailing edge of an oceanic basin. The Arabian platform faced an actively spreading oceanic crust. The Comanchean shelf fringed a large continental interior, whereas the Arabian shelf bordered a very small craton. Consequently, general rates of rock accumulation during the Early and middle Cretaceous were up to two times greater on the Comanchean shelf.

The shelf margin location was partly controlled by tectonic features, partly by rates of sediment accretion, and partly by relative sea level position. On the Comanchean shelf the Valanginian and the Barremian-early Aptian shelf margins were ramps that built out faster than up, whereas on the southeastern Arabian platform during the Hauterivian-Aptian the platform built up rather than out.

During the Albian the Comanchean shelf margin built up and out equally. The Oman part of the Arabian platform was drowned and flooded in the Albian by terrigenous sediments prior to resumption of upbuilding during the Cenomanian. Cenomanian eustatic sea level changes altered the succession of carbonate depositional systems in Oman, while carbonate production on the Comanchean shelf was terminated by this same change. The Oman-United Arab Emirates carbonate platform was terminated by tectonic activity associated with Turonian-Coniacian obduction of the Tethyan oceanic crust.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.