A Multidisciplinary Integration of Selected Saudi Arabian Carbonate Unconformities

F.O. Meyer and G.W. Hughes

Saudi Aramco, Box 5000, Geological R&D, X-4800, Dhahran 31311, Saudi Arabia

The recognition and correlation of unconformities is critical to any sequence stratigraphic analysis. Unfortunately, the identification of unconformities based exclusively on sedimentologic or shifts in depositional facies data is not without ambiguity and thereby contributes to the development of radically different sequence stratigraphic models. We seek to constrain the delineation of significant depositional sequences by employing a multidisciplinary integration for the delineation of unconformities and the sequence stratigraphic framework of Arabian Platform carbonates. The methodology employed includes integration of sedimentologic, micropaleontologic, diagenetic, and stable isotopic data. This approach requires closely spaced sampling across the unconformity that begins three to four feet below and extends one to two feet above the target surface. Sample collection is generally on a half foot increment in cores whereas on outcrop we collect rock at the base and top of each bed. Macroscopic features in core or outcrop are augmented by thin-section and stable isotope analyses. This approach has been used successfully to distinguish seven significant formation and intra-formation unconformities from minor Jurassic and Cretaceous sedimentary discontinuities. Our initial work shows that all significant unconformities exhibit dramatic shifts across the boundary in the biofacies and lithofacies components.

Meyer, F. O., and G. W. Hughes, 2000, A multidisciplinary integration of selected Saudi Arabian carbonate unconformities: GeoArabia, v. 5, p. 144.