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Submarine-fan and slope facies of Tonkawa (Missourian-Virgilian) sandstone in deep Anadarko basin

Conference · · Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:5898402

The Tonkawa sandstone (Missourian-Virgilian) in the Anadarko basin consists of upper, middle, and lower sandstone units, separated by intervening shales. The lower Tonkawa sandstone consists of coarse to pebbly sandstones deposited in thick, coarsening-upward sequences. Gross sand isopachs outline northwest-southeast oriented linear thicks that extend for tens of miles. The middle Tonkawa sandstone consists of thin- and thick-bedded fine-grained sandstones displaying wavy and flaser bedding, convolute laminae, and some small-scale cross-laminae. The upper Tonkawa sandstone caps the entire sequence and is overlain by oolitic limestones. The authors interpret the lower Tonkawa sandstone to represent a submarine-fan complex for the following reasons. The regional setting indicates that the sandstones were deposited tens of miles from the shelf edge. The areal geometry of sandstones indicates channelized flows that coalesced to form an overall fanlike geometry. The middle Tonkawa sandstones are interpreted as a sequence deposited on the basin slope. Regional setting indicates that the unit is located immediately basinward of the shelf edge and that it progrades over the lower Tonkawa sandstone. Deposition as sheets or aprons is suggested by lateral continuity, at least for several miles, of individual beds. The lower and middle Tonkawa sandstones represent offshelf deposition in an interior basin setting. If the deep water sandstones in interior basins are indeed as common as they appear to be in the Anadarko basin, then it is crucial for stratigraphic exploration that we recognize and document such deposits in other interior basins as well.

Research Organization:
ARCO Exploration Co., Dallas, TX
OSTI ID:
5898402
Report Number(s):
CONF-8410269-
Journal Information:
Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 68:12; ISSN AAPGB
Country of Publication:
United States
Language:
English