Late Precambrian Rocks of the Northeastern Great Basin and Vicinity

Abstract

The late Precambrian rocks of the northeastern Great Basin and adjacent areas occur as three distinct sedimentary-rock associations with quite different geographic distributions. These associations, designated as Subprovinces I, II, and III in this investigation, reflect in varying degrees different histories of weathering, erosion, and sedimentation and perhaps different source areas. Because of inadequate exposure, complex thrust faulting, and varying degrees of regional metamorphism, the relationships between the subprovinces are not clear. A gradational contact indicative of continuous clastic deposition occurs between late Precambrian and Cambrian rocks west of the Wasatch Range, while a slight angular uncomformity indicative of late Precambrian uplift and erosion exists between rocks of these ages within and east of the Wasatch Range. Textured and mineralogical evidence from late Precambrian and Paleozoic rocks in the northeastern Great Basin and adjacent areas indicates widespread post-late Paleozoic regional metamorphism in this area.