Regional Structural Synthesis, Wyoming Salient of Western Overthrust Belt

Abstract

Surface geologic mapping, regional and high-density reflection seismic data and information from approximately 370 wells have been combined to describe geometrically that area of the Western Overthrust belt between the Snake River plain and the Uinta uplift. Particular care has been taken to verify two-dimensional interpretations of multiple thrust sheets by linear restoration. By establishing equivalence of pre-thrust lengths of affected beds, one can gain confidence in interpreted structural geometries, as well as generate data in regard to internal shortening and deformation intensity. Because of irresoluable geometric problems within sections, 47 cross sections were developed at roughly 6-mi (10 km) spacing to help verify changes in displacement or placement of key st uctural elements. Displacements of 0 to 32 mi (0 to 51 km) have been demonstrated. Jurassic to Paleocene (Sevier) thrusts were active across a previously deformed cratonic shelf terrane and interacted with active structural elements such as the Uinta uplift, Gros Ventre Range, and Moxa arch. Thrusts are progressively younger to the east except for the Darby-Prospect pair in which the Darby system is younger.