Frontier Formation, Wyoming: wave-dominated deltas, shelf sand sheets, tectonics, and eustacy in Interior seaway

Conference · Sat Aug 01 04:00:00 EDT 1987 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:5752132

Winn, R D

Shale, sandstone, and minor conglomerate, coal, and bentonite of the Cenomanian to Coniacian Frontier Formation were deposited in wave-dominated deltas and shelf environments on the west side of the Interior seaway. Frontier hydrocarbon production occurs mostly where deltaic and shelf sandstones pinch out into marine shale (e.g., Powder River and Green River basins). Shelf sandstones are in sheets that extend for tens of kilometers offshore and downcurrent from deltaic sources. Core and outcrop show shelf sandstones to consists mostly of high-angle cross-stratification. Also present in shelf sandstones are numerous cross-set reactivation surfaces, scour surfaces, hummocky cross stratification, wave and current-ripple lamination, interbedded mudstone, and burrowing. Intermittent, storm-generated geostrophic flows are inferred to have been the major shelf sedimentation process. Storms apparently moved pebbles over 7 cm long. Frontier Formation thickness trends indicate a provenance mostly in the Idaho portion of the Sevier orogenic belt and suggest influence of large basement features on deposition. A question concerns influence of tectonics versus eustacy on sandstone occurrence. Comparison of sandstone ages with published coastal-onlap, eustacy, and transgressive-regressive curves allows correlation of the Torchlight, Wall Creek Member, Tuner Sandy Member, probably the Peay, and equivalent sandstones (and most production) with eustatic events, although simultaneous intrabasin deformation has been documented. Other sandstones of the Belle Fourche Member and the Emigrant Gap member and equivalents appear to have been controlled more by tectonic events.

• Research Organization: Marathon Oil Co., Littleton, CO
• OSTI ID: 5752132
• Report Number(s): CONF-870915-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 71:8
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
CARBONACEOUS MATERIALS
COAL
CONGLOMERATES
ENERGY SOURCES
FEDERAL REGION VIII
FOSSIL FUELS
FUELS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
MATERIALS
NORTH AMERICA
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEDIMENTATION
SHALES
TECTONICS
USA
WYOMING