UNITED STATES DEPARTMENT OF INTERIOR GEOLOGICAL SURVEY Depositional History and Petroleum Geology of the Permian Phosphoria, Park City, and Shedhorn Formations, Wyoming and Southeastern Idaho James A. Peterson U.S. Geological Survey Missoula, Montana Open-File Report 80-667 1980 This report is preliminary and has not been edited or reviewed for conformity with U.S. Geological Survey standards or stratigraphic nomenclature CONTENTS introduction""1 •»•"'••••••— -«-»• .•••i •••••• •miii«««.«.,-.«.•— _»«.M»iw«>~.,.. n .mu,. jm. ,^ >-.,.>_.._«_ ,.._ «•«..._ r «_...•.»•. ^^ Acknowledgment s ———————————————————————— - —• ———— T* —————————— 2a Regional structure and paleostructurer——————————————————————————— 2a Regional stratigraphy and depositional setting ————— ' ——————————————— 6 Phosphoria stratigraphy and depositional setting ———————————————————— 7 Origin and distribution of Phosphoria facies ———————————————————— 8 First (P10 - P30) cycle (Grandeur Member) —————————————————— 9 Second (P30 - P70) cycle ———————————————————————————————— 10 P30 - P35 subcycle (Mead Peak Member) ————————————————— 10 P35 - P40 subcycle (lower Franson Member) —————————————— 12 P40 - P50 subcycle (middle Franson Member) ————————————— 13 P50 - P70 subcycle (upper Franson Member) —————————————— 14 Third (P70 - P90) cycle ———————————————————————————————— 15 P70 - P75 subcycle (Retort Member) ———————————————————— 16 P75 - P80 subcycle (Tosi Member) —————— . —————————————— 17 P80 - P90 subcycle (upper Ervay Member) ———————————————— 17 Lower Dinwoody Formation——————————————————————————————————————— 18 Dolomitization ——————————————————————————————————————————————— 20 Stratigraphic evidence for Permian paleostructural growth —————————————— 21 Summary of depositional history —————————————————————————————————— 22 Petroleum geology ————————————————————————————————————————————— 24 Reservoir and source rock distribution———————————————————————— 25 Franson Member ——— ———————————————————————————————————— 25 oource Migration patterns and depth of burial ———————————————————————— 27 usions~"™~~~~""~~"~~""~"""""~"~"~™"~*~"~"~™""™"~"~"~""u™^'™™™"~*~*~"~"~™~"~~*~~™~'"~'>~™~"~""" — —•«.«•«••«••-»—• <£o Selected references ————: ——————————————————— - —————————————————— 29 ILLUSTRATIONS (All illustrations are in pocket) Plate 1. Map A. Index map showing main structural features in area of study, reference stratigraphic section localities, and location of cross-section. Map B. Index map showing main paleostructural features affecting facies distribution in Phosphoria Formation and equivalent strata. Figure 1. Correlation chart of main Permian stratigraphic units. Plate 2. Figure 2. Cross-section A - A*, Sublett Range, Idaho to Wind River Range, Wyoming, showing relationship between middle and upper Paleozoic Phosphoria basin, Bannock high, and Wyoming shelf stratigraphic units. Figure 3. Cross-section B - B*, Sublett Range, Idaho to Powder River basin, Wyoming, showing distribution of facies in Phosphoria, Park City, and Goose Egg Formations. Plate 3. Figure 4. Cross-section C - C 1 , southeastern Idaho to Wind River Range, Wyoming, showing distribution of main organic carbonate buildups in Franson and Ervay Members of the Park City Formtion. Figure 5. Cross-section D-D1 , southeastern Idaho to northwestern Wyoming, showing distribution of main organic carbonate buildups in Franson and Ervay Members of Park City Formation. Plate 4. Figure 6. Representative Permian surface and subsurface stratigraphic sections of basinal, shelf margin, carbonate shelf, and redbed-evaporite facies. Figure 7. Cross-sections illustrating phases of cycle development in marker-defined units of the Phosphoria, Park City, and Goose Egg Formations. Figure 8. Schematic diagrams illustrating effects of datum selection in construction of cross-section B - B 1 . Plate 5. Figure 9. Structural-stratigraphic cross-section E - E*, Bighorn basin, Wyoming. Figure 10. Structural-stratigraphic cross-section F - F 1 , Bighorn ba s in, Wyoming. Figure 11. Structural-stratigraphic cross-section G - G 1 , Wind River basin, Wyoming. Figure 12. Cross-section H - H 1 , southwestern Wyoming to south- central Wyoming, showing distribution of main organic carbonate buildups in the Franson and Ervay Members of the Park City Formation. Plate 6. Map C. Isopach map of net carbonate rock in the Franson Member of the Park City Formation, showing dolomite and chert facies and distribution of porous carbonate rocks in the Wyoming-Idaho overthrust belt. Map D. Isopach map of net carbonate rock in the Franson Member of the Park City Formation, showing dolomite, anhydrite, and redbed facies, and distribution of porous carbonate rocks in Wyoming east of the Wyoming-Idaho overthrust belt. Plate 7. Hap £. Isopach map of net dark high-organic shale, sandstone, and phosphorite in the P30 - P70 cycle, and distribution of porous carbonate rock in the Franson Member of the Park City Formation in the Wyoming-Idaho overthrust belt. Hap F. Isopach map of net dark high-organic shale, sandstone, and phosphorite in the P30 - P70 cycle, and distribution of redbed, anhydrite, and porous carbonate facies in the Franson Member of the Park City Formation in Wyoming east of the Wyoming-Idaho overthrust belt. Plate 8. Hap G. Isopach map of net carbonate rock in the Ervay Member of the Park City Formation, showing dolomite facies, distribution of porous carbonate rock, and the upper cherty shale member of the Phosphoria Formation, and position of the Bannock high. Map H. Isopach map of net carbonate rock in the Ervay Member of the Park City Formation showing dolomite facies and distribution of porous carbonate rock, anhydrite facies, and redbed facies in Wyoming east of the Wyoming-Idaho overthrust belt. Plate 9. Map I. Isopach map of dark high-organic shale, sandstone, and phosphorite in the P70 - P90 cycle, showing distribution of porous carbonate rock in the Ervay Member of the Park City Formation and distribution of cherty shale facies in the Wyoming-Idaho overthrust belt. Map J. Isopach map of dark high-organic shale, sandstone, and phosphorite in the P70 - P90 cycle, showing distribution of redbed, anhydrite, and porous carbonate rocks in the Ervay Member of the Park City Formation in Wyoming east of the Wyoming-Idaho overthrust belt. Plate 10. Map K. Isopach map, base of the Meade Peak Shale Member of the Phosphoria Formation (P30 marker) to the top of the Mississippian Madison Limestone, showing effects of pre-Phosphoria paleostructure and distribution of Darwin Sandstone Member of the Amsden Formation in Wyoming-Idaho overthrust belt. Map L. Isopach map, base of the Meade Peak Shale Member of the Phosphoria Formation (P30 marker) to the top of the Mississippian Madison Limestone, showing effects of pre-Phosphoria paleostructure and distribution of Darwin Sandstone Member of the Arasden Formation in Wyoming east of the Wyoming-Idaho overthrust belt. Plate 11. Map M. Isopach map, top of the Lower Cretaceous Dakota Sandstone to the top of the Phosphoria Formation and equivalent strata, showing suggested petroleum migration system and distribution of porous carbonate rock in the Park City Formation. Plate 12. Map N. Isopach map of the total Mesozoic section, showing suggested petroleum migration system and distirbution of porous carbonate rocks in the Park City Formation. Plate 13. Map 0. Map of drilling depth to the top of the Phosphoria Formation and equivalent strata in Wyoming, showing distribution of porous carbonate rock in the Park City Formation and oil fields producing from the Permian Phosphoria Formation and equivalent strata and the Pennsylvanian Tensleep Sandstone. iii TABLES Page Table 1. List of selected stratigraphic sections———————————————— 2b iv Depositional History and Petroleum Geology of the Permian Phosphoria, Park City, and Shedhorn Formations, Wyoming and Southeastern Idaho By James A. Peterson ABSTRACT Integrated studies of over 500 subsurface control sections and over 200 measured surface sections indicate that paleostructural growth of late Paleozoic structural elements, penecontemporaneous with deposition, markedly influenced the distribution of Permian cyclic lithofacies and carbonate reservoir belts in Wyoming and southeastern Idaho. Major paleostructural features include the Antler erogenic belt, Sublett basin, and Bannock high of southeastern Idaho, the Cortez-Uinta axis, the Wyoming shelf margin, and several paleostructures on the Wyoming shelf, some of which may represent early growth of features that later were involved in Laramide orogenic movements. Identification of paleostructural growth is based on interpretations of depositional environments of Permian facies, along with thickness patterns of Permian as well as pre- and post-Permian stratigraphic units. The Phosphoria Formation and the equivalent beds of the Park City Formation are divisible into two main depositional cycles, comprising the Franson and Ervay Members, which in turn are separated into subcycles, based on a marker-bed correlation framework, applicable throughout most of the Wyoming shelf province. Marker beds are thin sandy and shaly units that represent widespread clastic deposition across the shelf during low sea level stages at the termination of each subcycle. Reservoir beds are associated with early diagenetic dolomitization of coarse-grained skeletal carbonate mound belts, concentrated along paleostructural high areas of the shelf. Dolomitization of these beds is believed to have been caused by seepage-reflux of high-magnesium waters,