Hicks Dome

Location: Illinois, United States (37.534, -88.368 approx.)

Commodities: fluorite; beryllium; rare earth elements; thorium

Deposit model: sedimentary breccia above alkaline intrusive complex · unclassified

Geology

“Total upward displacement of the sedimentary rocks over the crest of Hicks Dome is about 4,000 ft and the dome's diameter is approximately 9 mi. The dome lies on the crest and near the northwest terminus of a large northwest-trending anticline. The anticline and dome are transected by many northwest-trending faults.” (Staatz and others (1979)) “Hicks Dome comprises more than 2,000 ft of Ordovician, Silurian, Devonian, and Mississippian sedimentary rocks, most of which are limestone, that have been pushed upward by an explosive intrusion of fluids. The Hunton Limestone of Devonian age is at the surface in the center of the dome, and younger rocks of Mississippian age are exposed on the flanks (fig. 3).” (Staatz and others (1979)) “The Diamond Creek district is approximately 8 mi north-northwest of the town of Salmon on the steep eastward-dipping slope of the Salmon River Mountains. The area is about 2,000 ft above the Salmon River, which flows along the eastern edge of the mountains. Diamond Creek crosses the district, and the principal veins occur on its drainage. Known veins in this small district however, are found in an area that is approximately 2 1/2 mi long by 0.5 mi wide. Thorium veins were emplaced in to quartzite and siltite of Precambrian Y age and into granodiorite of the Idaho batholith of Cretaceous age. Most of the veins occur in the sedimentary rocks, which are approximately the same age as and, in part, lithologically similar to the rocks of the Belt Supergroup that are found farther north. The two groups of rocks were deposited in separate basins. The sedimentary rocks appear to be more favorable hosts than the igneous batholithic rocks as veins as much as 25 ft thick have been found in the former, but they rarely exceed 2 ft in the latter.” (Staatz and others (1979))

Published resource estimates

As compiled by USGS USMIN from the cited studies. Resource classes follow the source; "approximate" flags values USMIN reports as approximations. These are not current company reserve statements.

Exploration and site history

• Discovery — Discovered by drilling while the St. Joseph Lead Company explored for oil or gas, 1952 (Brown and others (1954))

Record imported from USGS USMIN ver. 4.0 (June 2019). Developments after that date appear on facility records, not here; see the methodology.