Earth and Planetary Sciences ETDs

Publication Date

Spring 5-19-1968

Abstract

The southern Pilot Range is a slightly sinuous, north-trending mountain range located in the northeastern part of the Great Basin.

Approximately 18,500 feet of miogcosynclinal sedimentary rocks representing every system from late Precam­brian to Permian(?) are exposed in the southern Pilot Range. Because of intense faulting, many of the strati­graphic relationships between the formations are impossible to determine. Mesozoic and Tertiary strata are absent; however, Pleistocene Lake Bonneville deposits are wide­ spread, although thinly distributed. Small igneous stocks, dikes, and sills are common only in the southern two-thirds of the map area. Stocks are principally granodioritic. In several cases the intrusions of the stocks are structurally controlled, occurring primarily along a decollement thrust. Dikes and sills range from rhyolite to diorite; in places extremely silicic or mafic assemblages are present. A large pluton five miles north of the map area has been dated as Oligocene (Coats et al., 1967) and may indicate the age of the stocks.

Three periods of deformation are recorded in the southern Pilot Range. Mid-Mesozoic deformation is represented by thrusts, decollement thrusts, and related folding and tectonic thickening, thinning, and elimination of units, accompanied by regional metamorphism of late Precambrian and lower Cambrian strata. Early (?) Cenozoic deformation created a mosaic of high-angle faults within the range, truncating earlier structures. Later Cenozoic (Basin-Range) range-marginal faulting has blocked out the range and elevated it to its present height.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Lee Albert Woodward

Second Committee Member

Albert Masakiyo Kudo

Third Committee Member

J. Paul Fitzsimmons

Fourth Committee Member

Vincent Cooper Kelley

Document Type

Thesis

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