Earth and Planetary Sciences ETDs

Publication Date

7-18-1969

Abstract

Permian sedimentation in southwestern Utah was influenced by three principal depositional areas. These areas were the Oquirrh basin in north-central Utah, the Cordilleran geosyncline in eastern Nevada, and the Quemado-Cuchillo basin on the northern shelf of the Sonoran geosyncline in east-central Arizona and west-central New Mexico. Throughout Permian time, marine sediments and their well-developed beach and continental eolian sandstone equivalents were deposited within these basins and upon their surrounding shelves. Each of the three basins appear to have exerted their influence upon sedimentation during a discrete period of geologic time. Thus while one basin was sedimentationally active the other two basins were relatively quiescent. Remarkably similar beach and continental sandstone deposits are related to each of these basins and these sandstones all extend to a common depositional area in southwest Utah where they are vertically contiguous. This vertical juxtaposition or layering of littoral and beach sandstone facies that are related to three discrete sedimentational basins has been responsible for most of the problems involving Permian nomenclature and correlation in the Colorado Plateau province. Detailed stratigraphic analyses utilizing data from many wells and surface sections show that each continental sandstone facies has a basinal stratigraphic equivalent that consists primarily of interbedded carbonate and anhydrite with lesser amounts of sandstone and shale. The beach and basinal equivalents that have been established in this paper are: Cedar Mesa Sandstone equivalent to Elephant Canyon carbonates; Organ Rock Shale equivalent to Meseta Blanca Sandstone and Yeso evaporites and carbonates; White Rim Sandstone (at least lower 3/4ths) to Toroweap Formation; and upper White Rim Sandstone to lower­most (Gamma Member) Kaibab carbonate. Rock units underlying the Toroweap-White Rim Formations are shown to be younger to the south while the Kaibab Formation is inferred to be time-transgressive and a stratigraphic continuation of the Franson Member of the Park City Formation in northern Utah and southwestern Wyoming. The Permian-Triassic unconformity is most pronounced in extreme south-western Utah but decreases in magnitude northward and is not recognizable in north-central Utah. Early Triassic sedimentation in southern Utah appears to have been cyclical responding to one major subsiding sedimentational area, the Cordilleran Triassic basin. The early Triassic rock units in this area appear to be most characteristically onlap, and at least two and probably three of the early Triassic Moenkopi units discussed are not present at the type Moenkopi section in northern Arizona. The Woodside Formation is recognized in central Utah for the first time and the Sinbad and Timpoweap Formations are shown to be the same stratigraphic unit. It is recommended that the Moenkopi Formation either be redefined or raised to group status and that the principal Moenkopi reference section be designated the Virgin River valley. Structurally, most of southern Utah appears to have been a featureless platform throughout most of the Permian and early Triassic time.

Degree Name

Earth and Planetary Sciences

Level of Degree

Doctoral

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Sherman Alexander Wengerd

Second Committee Member

Lee A. Woodward

Third Committee Member

Roger Yates Anderson

Language

English

Document Type

Dissertation

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