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James J. Corboy1,
Charles Kerans2
(1) Department of Geological Sciences, The University of Texas at Austin, Austin, TX
(2) Bureau of Economic Geology, The University of Texas at Austin, Austin, TX
Abstract: Syntectonic Development of Early Permian Hueco Group Carbonate Platforms, Apache Canyon, West Texas
Carbonate platforms are extremely sensitive to sea level changes and are thus excellent monitors of composite relative sea level. Separation of this signal into eustatic and tectonic components allows highlighting of areas of syndepositional tectonic activity that may set up key hydrocarbon plays. The Early Permian (Wolfcampian) Hueco Group of the Sierra Diablo Range was deposited during late stages of foreland (Ouachita) deformation and provides an excellent example of the interplay of tectonics and eustacy in the generation of potential hydrocarbon reservoir-seal relationships.
Previous models of Wolfcampian deposition in the Permian Basin hold that active Ouachita tectonism was largely completed by middle Wolfcampian time and that following this carbonate platforms formed a contiguous rim to the Delaware and Midland Basins. Preliminary sections from the Hueco Group outcrops in Apache Canyon, Sierra Diablo Range suggest that tilting of basement uplifts throughout late Wolfcampian deposition controlled formation of isolated platforms with margins facing westward out of the main Delaware Basin. Three high-frequency sequences recognized within the Hueco group record progressive westward tilting and west to east retreat of the platform margin. Culmination of Ouachita tectonism was marked by a final phase of uplift and westward rotation of the Wolfcampian platform resulting in 600 ft of erosion of platform interior strata prior to Leonardian deposition. A single 1D profile near the western platform margin could be misinterpreted as a record of eustatic rise and backstepping in late Wolfcamp time as opposed to local uplift and westward tilting. New play concepts associated with this revised fault-block tectonic model of the middle through late Wolfcampian include isolated platforms on uplifted blocks and carbonate debris aprons and fans surrounding these blocks.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana