ABSTRACT: Geologic Evolution of Uinta-Piceance Basin Province, Northwestern Colorado and Northeastern Utah

S. Y. Johnson, M. L. Tuttle, B. H. Bryant, R. F. Dubiel, T. D. Fouch, K. J. Franczyk, V. J. S. Grauch, M. A. Grout, R. C. Johnson, C. M. Molenaar, D. J. Nichols, K. M. Nichols, V. F. Nuccio, Fred Peterson, J. K. Pitman, W. J. Perry, Jr., C. J. Potter, D. L. Sawatzky, R. W. Scott, Jr., E. R. Verbeek, R. B. Wanty

The Uinta-Piceance basin province (UPBP) has a complex Phanerozoic history characterized by five distinct phases of basin development. (1) The UPBP formed part of a continental platform shelf on the northwestern flank of North America during the early and middle Paleozoic. Cambrian through Mississippian strata consist mainly of carbonate rocks, shale, and quartzite; contain major unconformities; and thicken westward. (2) Pennsylvanian-Permian uplifts of the ancestral Rocky Mountain orogeny segmented this continental platform shelf into the Eagle, Paradox, and Oquirrh basins. Basin-margin tectonics and cyclic eustatic-climatic fluctuations strongly controlled deposition of the clastic, carbonate, and evaporitic fill of these basins. (3) During the early Mesozoic, the UPBP formed part o a slowly subsiding continental platform. Triassic-Jurassic rocks include eolian, alluvial, and lacustrine deposits that thicken and grade westward into marine facies. (4) Paleozoic and early Mesozoic strata in the westernmost part of the UPBP were thrust eastward during the late Mesozoic Sevier orogeny, causing subsidence in the adjacent foreland basin. The history of the UPBP part of this foreland basin is recorded by thick nonmarine deposits within and adjacent to the thrust belt that grade eastward into thinner accumulations of marine rocks. (5) The geometry and style of regional compressional deformation changed markedly with onset of the latest Cretaceous-Paleogene Laramide orogeny. Laramide uplifts segmented the UPBP foreland basin into the Uinta and Piceance intermontane lacustri e basins. The geometry of these lacustrine basins is notably different from that of the late Paleozoic segment basins.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990