DROSTE, HENK, Shell Research B.V., The Netherlands

ABSTRACT: Source Rock Development and Relative Sea-Level Changes in an Intra-Platform Basin: The Upper Jurassic Hanifa Formation of the Arabian Peninsula

The Upper-Oxfordian to Lower-Kimmeridgian Hanifa Formation was deposited in an intra-platform basin on the broad epeiric shallow-water carbonate platform that extended over much of the Middle East during the Mesozoic. The formation consists of organic-rich carbonate mudstones, bioturbated mudstones and sulphates. The organic-rich mudstones are considered to be one of the major hydrocarbon source rocks in the Middle East oil province.

The relations of vertical and lateral lithofacies associations, as deduced from wireline logs and cores, are interpreted in terms of superimposed relative sea-level changes. The source-rock development in the Hanifa Formation coincides with periods of third-order (eustatic) rise during an overall rapid second-order rise (subsidence). The high subsidence rate, in combination with significant mud supply from the basin margin, has resulted in a considerable thickness of source rock in the center of the intrashelf basin, where anoxic conditions prevailed.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.