Kings Canyon Mining District, Millard County, Utah, USAi

Regional Level Types
Kings Canyon Mining District	Mining District
Millard County	County
Utah	State
USA	Country

The Kings Canyon district is located about 60 mi southwest of Delta in west-central Millard County. The Kings Canyon mineral occurrences cover about 70 sq mi but were not discovered until the 1980s and there has been no production. Nonetheless, the area was intensively explored in the late 1980s, early 1990s, and again this century―including the drilling of over 200 exploration holes.
Kings Canyon is situated on the west flank of the Confusion Range in the Basin and Range Province. The Confusion Range is a gently west-dipping homocline of Devonian-age carbonate rocks. The massive, very thickly bedded, Middle to Upper Devonian Guilmette Limestone forms cliffs on the west side of the range. The underlying Middle Devonian Fox Mountain Formation is a poorly mapped and understood carbonate solution breccia/karst cave-fill unit. Most of the recognized Au deposits occur in or near the Fox Mountain Formation. The Fox Mountain is underlain by thickly bedded, ledge-forming, Middle Devonian Simonson Dolomite and the underlying Lower Devonian Sevy Dolomite with a few Au prospects farther east in these units (Krahulec, 2011). The only known intrusive rocks are two small feldspar (latite?) porphyry dikes and several breccias containing clasts of altered intrusive rocks exposed on the west side of the range in and near Boobs Canyon (Krahulec, 2011).
Gold mineralization occurs in cross-cutting, high-angle structures and as stratiform replacement of susceptible horizons (USGS Model 19c). The Au is commonly associated with partial or, more rarely, complete silicification. The alteration locally produces massive jasperoid bodies, but more commonly is selective and only 10% to 50% of the rock is silicified. Gangue minerals in the jasperoid include quartz, calcite, fluorite, and barite. Gold mineralization is also associated with Fe-stained and slightly to moderately decalcified limestone and dolomite along cross-cutting structures and along bedding (Zimmerman, 2009).
Four broad main areas of sedimentary rock-hosted Au mineralization in the Kings Canyon district (from southwest to northeast): Thompson Knoll/Boobs Canyon, Road Canyon, Crown/Royal zones, and King Top/Sunshine (Krahulec, 2011). The southeastern part of the district is within a Wilderness Study Area.