Geologic map of the Charleston quadrangle, Wasatch County, Utah (M-236)

By: R. F. Biek and M. Lowe The Charleston quadrangle lies on the south edge of a structural and topographic saddle between the Wasatch Range and Uinta Mountains. The quadrangle includes the southern part of Heber City and Heber Valley and the northern half of Round Valley, as well as parts of Deer Creek Reservoir and Wasatch Mountain State Park; the small communities of Charleston, Daniel, and Wallsburg are also in the quadrangle. The quadrangle also straddles the north edge of the Charleston-Nebo thrust sheet, and thus includes three distinct groups of rocks: (1) a nearly complete section of allochthonous Pennsylvanian rocks of the Oquirrh Formation that comprises the Charleston thrust plate; (2) para-utochthonous, southeast-dipping Jurassic and Triassic strata (Thaynes Limestone, Ankareh Formation, Nugget Sandstone, and Twin Creek Limestone) below the Charleston thrust; and (3) parts of the Big Cottonwood Formation (Upper Proterozoic), Tintic Quartzite (Middle to Lower Cambrian), and