Depositional history and petroleum geology of the Permian Phosphoria, Park City, and Shedhorn formations, Wyoming and southeastern Idaho

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.Phosphoria and Dinwoody sediments is interpreted to have resulted from the worldwide decline and extinction by Triassic time of major elements of the Paleozoic marine biotic assemblages which were largely responsible for the deposition of organic carbonate mound buildups and associated organic-rich sedimentary facies in the Permian and earlier Paleozoic beds.

Maps showing selected geology and phosphate resources of the Fossil Canyon quadrangle, Bear Lake and Caribou Counties, Idaho

“…1) (McKelvey and others, 1959;Peterson, 1980). The Phosphoria grades northward into the Shedhom Sandstone in south-central Montana and northwestern Wyoming, and southward and eastward into the Park City Formation in northeastern Utah and west-central Wyoming (McKelvey and others, 1959).…”

A New Approach to Fluid-Flow Modeling of Directional Permeability in a Faulted Anticline, Little Sand Draw Field, Big Horn Basin, Wyoming.

“…The Phosphoria is separated by major (Peterson, 1980). These depositional sequences are recognized in the Big Horn basin, from bottom to top, as the Grandeur, Meade Peak, Franson, Retort, and the Ervay members of the Phosphoria Formation.…”

“…Permian strata in the Big Horn basin were deposited on the Wyoming shelf ( Figure 2-3), a marine carbonate ramp positioned east of the foreland Sublette basin of Utah, Idaho and western Wyoming (Peterson, 1980;Maughan, 1979;Coalson and Inden, 1990). …”

Maps showing selected geology and phosphate resources of the Diamond Flat quadrangle, Caribou County, Idaho

“…I e d. a-t (McKelvey and others, 1959;Peterson, 1980). The Phosphoria grades northward into the Shedhorn Sandstone in south-central Montana and northwestern Wyoming, and southward and eastward into the Park City Formation in northeastern Utah and west-central Wyoming (McKelvey and others, 1959).…”