The thrust belt in Southwest Montana and east-central Idaho

Abstract

The leading edge of the Cordilleran fold and thrust belt in southwest Montana appears to be a continuation of the edge of the Wyoming thrust belt, projected northward beneath the Snake River Plain. Traces of the thrust faults that form the leading edge of the thrust belt are mostly concealed, but stratigraphic and structural evidence suggests that the belt enters Montana near the middle of the Centennial Mountains, continues west along the Red Rock River valley, and swings north into the Highland Mountains near Butte.