Abstract

The concept of thrusting of miogeosynclinal rocks eastward toward the craton along laterally continuous zones of faults in western Utah (Misch, 1960; Roberts and others, 1965) has been challenged by Eardley (1968, 1969). He has presented an hypothesis involving primary uplifts marked by local marginal upthrusts and large-scale gravity slide masses that have moved in various directions over adjacent basins. In discussing his hypothesis, Eardley suggests that the San Francisco Mountains consist of a gravity-driven plate that glided southwest from a primary uplift in the Beaver Mountains.

Detailed mapping in the Beaver and San Francisco Mountains indicates that there is no glide surface present as hypothesized by Eardley (1969), but rather the San Francisco thrust mapped by East (1966) in the southern San Francisco Mountains dips northward and underlies the northern San Francisco and Beaver Mountains. Drag features near the thrust suggest yielding toward the east, not the southwest. Thus, the evidence supports eastward yielding along a laterally continuous thrust rather than gliding in various directions from locally uplifted areas.

First Page Preview

First page PDF preview
You do not currently have access to this article.