--> ABSTRACT: Compaction and the Dynamics of Carbonate Platform Development: Insights from the Permian Basin, by D. Hunt and W. M. Fitchen; #91021 (2010)

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Compaction and the Dynamics of Carbonate Platform Development: Insights from the Permian Basin

HUNT, D., W. M. FITCHEN

Understanding how compaction can influence the dynamics of carbonate platform development, has important implications for the prediction of paleotopography, paleokarst development, and consequent reservoir facies distributions of both depositional and diagenetic origin.

Compaction-modified platform architecture's are best developed where platforms prograde over (1) antecedent aggradational and/or erosional margins, or (2) basinward thickening toe-of-slope wedges. Compaction-induced differential subsidence can substantially modify platform physiography during and/or after deposition. When differential compaction occurs during deposition, then shelf strata steepen and thicken towards the offlap break to form a characteristic 'roll-over' type platform margin. In this situation, extensive syn-depositional fractures (neptunean dikes) are expected in the basinward rotated strata located immediately shelfward if the platform margin. Such fracturing likely contributes to the highstand shedding of platform margin talus as megabreccia onto the immediate foreslope. In contrast, when differential compaction occurs after deposition (during lowstands), then compaction-'enhanced' sequence boundaries are formed. These are recognized by a basinward-dipping sequence boundary, and comparably rotated toplap strata onlapped by less steeply dipping strata of the succeeding sequence. Significantly, toplap strata show the greatest rotation and deformation above compactional hinges developed over antecedent platform margins where outcrop study shows the most penetrative paleokarst is formed.

Relatively simple geometric recognition criteria developed from outcrop studies permit prediction of compaction-modified sequences on regional seismic lines. Seismic-scale examples of compaction-modified sequences are described from outcrop in the Sierra Diablo, Brokeoff Mountains, and Guadalupe Mountains of west Texas and New Mexico. Comparable sequence geometries and internal stratal patterns are observed on 2-D seismic sections through equivalent sequences in the Permian Basin subsurface.

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.