Antelope Springs Mining District, Beaver County, Utah, USAi

Regional Level Types
Antelope Springs Mining District	Mining District
Beaver County	County
Utah	State
USA	Country

The Antelope Springs (McGarry) mining district is located on the Millard and Beaver County line about 15 miles northeast of Milford. The district has been an insignificant Ag producer. The district had several small, generally unsuccessful drilling campaigns in the 1960s, 1980s, and 1990s. The Pay Streak Ag-Pb-Au mine is believed to be one of the few productive properties.

The district lies on the northern end of the Mineral Mountains of the Basin and Range Province. To the south, the Mineral Mountains expose a large, mostly gray, alkalic, high-silica, composite Oligocene-Miocene (25 to 17 Ma) granite, monzonite, and syenite batholith (80 square miles), the largest exposed batholith in Utah. The batholith was strongly rotated to the east (40°–85°) in the middle to late Miocene, so that the east side of the mountain is closer to the paleo-top of the batholith (Coleman and others, 2001).

The strata in the Antelope Springs district are structurally complex Lower Cambrian quartzites thrust over Middle (?) Cambrian carbonates. Scattered mineralization has been prospected in the carbonates adjacent to the northern margin (side) of the Mineral Mountain batholith (Liese, 1957). The mineral occurrences are generally small Ag-Pb-Zn ±Cu vein and replacement deposits (USGS Model 22c). The primary sulfide/ore minerals are pyrite, argentiferous galena, chalcopyrite, and presumably sphalerite with abundant barite. These ores may also be geochemically anomalous in As, Hg, Mn, Sb, and Te. The prospects farther south, near the batholith, have more Cu ±W and less Pb-Zn-Ba. Adjacent to the batholith the Cambrian carbonates are metamorphosed to marble and hornfels. On the extreme west flank of the range, the carbonates
are metamorphosed locally to a large body of massive, foliated, fibrous tremolite (16 million tons; Crawford and Buranek, 1942) (USGS Model 18e).