PETERSON, JAMES A., Department of Geology, University of Montana, Missoula, MT 59812-0001

ABSTRACT: Carboniferous-Permian (Late Paleozoic) Hydrocarbon System, Rocky Mountains, Great Basin U.S. Region -- Major Historic Exploration Objective

Carboniferous-Permian rocks make up an important closely related regional hydrocarbon source-reservoir System covering most basins of the Rocky Mountain and Great Basin region. The System includes oil and gas accumulations in the Williston basin and Sweetgrass Arch areas of Montana and North Dakota; the Bighorn, Wind River, and Powder River basins of Wyoming; the Uinta, Sand Wash, and Piceance basins of NE Utah and NW Colorado; the Paradox basin of the Four Corners area; and the basins of east-central Nevada. More than 400 hydrocarbon accumulations, at least 20 greater than 100 MM bbls. each, are present, including Rangely, the largest Rocky Mountain field, and the central Utah partly-eroded Tar Sand Triangle stratigraphic trap heavy oil and tar accumulation, arguably the largest (probably 30 billion barrels oil equivalent or more) original in-place hydrocarbon accumulation of the United States.

Regional and local detail ed palinspastic, stratigraphic, paleotectonic, source rock burial depths, and maturity projections aid in geologic analyses of these extensive hydrocarbon deposits. The estimated volume of total original hydrocarbons generated and accumulated in these Late Paleozoic rocks elevates this System to a major position in the Rocky Mountains-Great Basin U.S. oil and gas Province.

AAPG Search and Discovery Article #90915©2000 AAPG Rocky Mountain Section, Albuquerque, New Mexico