Skip to Main Content
Book Chapter

Lower Permian (Wolfcampian) Carbonate Shelf-Margin and Slope Facies, Central Basin Platform and Hueco Mountains, Permian Basin, West Texas, USA

By
Gregory P. Wahlman
Gregory P. Wahlman
Wahlman Geological Services, LLC, 8903 Westerkirk Drive, Austin, Texas 78750 USA e-mail: gregwahlman@aol.com
Search for other works by this author on:
Douglas R. Tasker
Douglas R. Tasker
BP Trinidad and Tobago, 5-5a Queen’s Park West, Port of Spain, Trinidad and Tobago
Search for other works by this author on:
Published:
January 01, 2014

Abstract

Lower Permian (Wolfcampian) carbonate platform margin depositional profiles and stratigraphic architecture were controlled primarily by the type of reef community that characterized the time, peak icehouse glacioeustatic sea-level fluctuations, and regional tectonic pulses from the paleocontinental collision along the southern margin of the basin. During transgressions, mound-shaped reef cores began growth in sub-wavebase, low-light (oligophotic), upper slope settings. The reef mound communities quickly diversified, and the reef mounds aggraded and shallowed upward through the euphotic zone, eventually reaching wavebase during early highstand, and graded upward into progradational crestal shelf-margin shoals during late highstand. Reef mound growth seaward of and downdip from the crestal platform margin shoals resulted in distally-steepened platform margin profiles, which persisted throughout Permian time. Wolfcampian reef mound facies are composed of bafflestones-boundstones with frameworks of phylloid algae, calcisponges and heliosponges, and fenestrate and ramose bryozoans, which were encrusted by Tubiphytes, laminar encrusting red algae (Archaeolithoporella), fistuliporid bryozoans, and microbialite. Peloidal cement matrices are common. Syndepositional to early marine botryoidal radial fibrous cements are generally sparse but are more common in windward margin buildups. Reef mound cores are surrounded by shallowing-upward skeletal packstone to grainstone flank beds. Crestal shelf-margin shoals are composed of medium-to coarse-grained grainstones with fusulinids, Tubiphytes, and robust dasycladacean algae, and contain small Tubiphytes patch reefs.

Early Permian icehouse glacioeustatic sea-level fluctuations and episodic tectonic pulses created erosional paleotopography on unconformities near the base of the Wolfcampian and at the mid-Wolfcampian. On the eastern margin of the Central Basin Platform, Lower Hueco Group (lower Wolfcampian) carbonate bank complexes composed of reef mounds and packstone-grainstone flank beds grew along an erosional escarpment on the underlying Bursum Formation (uppermost Pennsylvanian), as seen at South Cowden (8790 Canyon) Field, Ector County, Texas. The escarpment depositional slope was >10°. Reservoir porosity in the Lower Hueco platform margin carbonate banks was greatly enhanced by subaerial exposure and meteoric dissolution at the overlying mid-Wolfcampian unconformity. Lithoclastic-skeletal debris flows are common in Wolfcampian forebank, deeper water, slope-to-basin facies.

Outcrop analogs for the subsurface carbonate platform margin banks and forebank slope-to-basin facies are well exposed in the Hueco Group of the western outliers of the Hueco Mountains in far west Texas, which were paleogeographically located along the western (leeward) margin of the Diablo Platform and adjacent Orogrande Basin. Platform margin banks prograded over an irregular paleotopographic surface on the sub-Hueco Group erosional unconformity. The leeward upper slope to shelf-margin reef mounds have phylloid algal-dominated core facies with only sparse radial fibrous cements, which graded rapidly upward near wavebase into crestal shelf-margin grainstone shoals with Tubiphytes patch reefs. Proximal forereef, upper slope facies are composed of autochthonous upper slope crinoidal-fusulinid packstones, burrowed dark mudstones, and productid brachiopod wackestones and have interbedded allochthonous tongues of forereef grainflows, turbidites, and lithoclastic-skeletal packstone debris flows. More distal slope-to-basin facies are composed of autochthonous dark cherty nonburrowed mudstones-wackestones with interbedded allochthonous lithoclastic-skeletal packstone debris flow deposits and turbidites. Slope facies distributions reflect icehouse glacioeustatic sea-level fluctuations.

You do not currently have access to this article.

Figures & Tables

Contents

SEPM Special Publication

Deposits, Architecture, and Controls of Carbonate Margin, Slope and Basinal Settings

Klaas Verwer
Klaas Verwer
Statoil ASA, Sandsliveien 90 5124, Bergen, Norway
Search for other works by this author on:
Ted E. Playton
Ted E. Playton
Chevron Energy Technology Company, 1500 Louisiana St, Houston, Texas 77002, USA
Search for other works by this author on:
Paul M. (Mitch) Harris
Paul M. (Mitch) Harris
Chevron Energy Technology Company, 1500 Louisiana St, Houston, Texas 77002, USA
Search for other works by this author on:
SEPM Society for Sedimentary Geology
Volume
105
ISBN electronic:
9781565763241
Publication date:
January 01, 2014

References

Related

Citing Books via

A comprehensive resource of eBooks for researchers in the Earth Sciences

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal