The stratigraphy of the eastern Arabian Peninsula should accurately record Cretaceous sea level changes owing to long-term regional tectonic quiescence and carbonate platform deposition. The setting is thus not dependent on coastal or shelf-edge processes. We have constructed from well studies and numerous published sources a regional sea level curve for the Cretaceous using paleobathymetric relations within precisely dated stratigraphic sequences adjusted for isostatic response to sea level motion. The isostatic response for any section encountered in a well can be calibrated by constructing a depth/burial curve which is corrected for compaction, sediment loading, thermal cooling, and tectonic subsidence.

The Cretaceous of the eastern Arabian Peninsula is comprised of three lithic sequences bounded by four regional unconformities. The lithic sequences are: the Lower Cretaceous Thammama Group, shallow-water carbonate rocks; the middle Cretaceous Wasia Group, shallow-water carbonate rocks; and the Upper Cretaceous Aruma Group, deep-water shales changing laterally into shallow-water limestones. The unconformities, agreeing closely with eustatic sea level lows, occur during: the latest Jurassic/earliest Cretaceous, the middle Aptian, the late Cenomanian-Turonian, and the latest Cretaceous/earliest Paleocene. The Turonian exposure was reinforced by regional tectonic upwarp. Low stands of less magnitude occur during the Barremian, late middle Albian, and middle Cenomanian. A Valanginian unco formity, recognized in the stratigraphic sequence of eastern Saudi Arabia, does not appear to be regional in extent. In the Upper Cretaceous (Coniacian-late Campanian), the effect of regional tectonic subsidence on the sedimentary facies overshadows the general eustatic high stand.

Our examination of carbonate provinces elsewhere indicate that the major unconformities are not localized and therefore probably represent global eustatic sea level lows.

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