Geologic map of the Harley Dome quadrangle, Grand County, Utah (M-157)

By: G. C. Willis

The Harley Dome quadrangle is located on the southern flank of the Uinta Basin in eastern Utah. The oldest exposed formation is the Cretaceous Aptian to Albian Cedar Mountain Formation. It is overlain by the Cenomanian Dakota Sandstone, which is mapped as three informal members. The youngest exposed formation is the Cretaceous Turonian to Campanian Mancos Shale which, in the quadrangle, consists of the Tununk Member, the Ferron Sandstone Member, the lower part of the Blue Gate Member, and the Prairie Canyon Member. The Tununk Member is mapped in three parts: a lower shale, the Coon Spring Sandstone Bed, and an upper shale. The quadrangle is in a strongly erosional regime; thus, alluvial, colluvial, and eolian surficial deposits are thin and scattered. The thickest surficial deposits mantle pediments that range from 20 to 360 feet above nearby drainages. The oldest pediment mantle contains the Lava Creek B volcanic ash, which was erupted 620,000 years ago.

Other Information:
Published: 1994
Pages: 18 p.
Plates: 2 pl.
Scale: 1:24,000
Location: Grand County
Media Type: Paper Map