GRANITES, GRUSSES, AND SHERMAN EROSION SURFACE, SOUTHERN LARAMIE RANGE, COLORADO-WYOMING

Abstract

Recent mapping of southern part of Laramie Range in Wyoming- Colorado reveals that smooth Sherman erosion surface there is developed principally on one type of rock, Precambrian Trail Creek granite facies of Sherman granite; other crystalline rocks support more rugged, parkland-tor topography; distinctive petrographic characteristic of Trail Creek granite is extensive, high- temperature oxidation of Precambrian age; disintegration to gruss is so rapid and complete that outcrops are scarce, and smooth, gently rolling topography results.