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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 922

Last Page: 923

Title: Pennsylvanian Fan-Delta Deposition, Mobeetie Field, Texas Panhandle: ABSTRACT

Author(s): Shirley P. Dutton

Article Type: Meeting abstract


A prism of Pennsylvanian and Lower Permian arkosic sandstone and conglomerate (granite wash) was deposited in alluvial fans and fan deltas north of the Amarillo uplift in the Anadarko basin. Deposits adjacent to the main bounding fault are as much as 1,500 m thick but thin to 30 m within approximately 60 km of the uplift. Mobeetie field, in northwest Wheeler County, is located 16 km north of the basement uplift, at the northern limit of upper Missourian granite-wash sedimentation. Oil and gas are produced from a sequence of Missourian granite wash and interbedded carbonate rocks.

The oldest Missourian carbonate unit and the overlying classic unit form a representative depositional cycle. In the carbonate unit, a series of elongate, phylloid-algal mounds composed of algae-foram wackestones and packstones developed along strike and separated the open shelf from a more restricted lagoonal environment. Progradation of coarse-grained clastics onto the carbonate shelf halted carbonate production.

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Braided streams breached low areas along the algal-mound trend and deposited distal fan-delta sediments on the shelf basinward of the mounds. Coarse conglomeratic sandstones were deposited directly on carbonates, but do not show a progradational, coarsening-upward sequence. Carbonate deposition recommenced following waning of clastic influx and subsidence of the fan delta. Algal mounds developed preferentially on shallow platforms built by the previous cycle of clastic deposition. Distal parts of the two youngest fan-delta cycles were reworked along strike, and terrigenous grains were oolitically coated in high-energy oolite shoals.

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