| Basis for focus area |
This focus area covers the belt stretching from the Greater Tintic area in the east to Steptoe Valley in the west, covering the most well agreed upon portion of the Tintic-Deep Creek mineral/igneous/structural belt/lineament and is based on belt outlines in Christiansen and others (1986) and Rowley (1998) and on mineral districts as defined in Krahulec (2018b) and Tingley (1998). The focus area includes the major Tintic and Spor Mountain mining districts in Utah and the following moderate and minor Utah districts: Blue Bell, Columbia-East Erickson, Crater Bench, Desert Mountain, Drum Mountain, Dugway, Erickson, Fish Springs, Honeycomb Hills, Keg Mountain, Long Ridge, Mount Nebo, Sand Pass, Santaquin, Spring Creek, Trout Creek, West Tintic, Willow Springs and the following Nevada mining districts: Eagle, Warm Springs, Schelbourne, Selgel, Silver Canyon, Ruby Hill, Muncy Creek and White Cloud. There are many mineral systems in the belt but the majority fall under porphyry Cu-Mo-Au, though the world-class Spor Mountain beryllium deposits are the notable exception and classify under Climax-type. Christiansen and others (1986) and Rowley (1998) both continue the belt farther into Nevada but there is not good agreement on its extent past Steptoe Valley. |
| Identified resources |
Identified resources of copper, indium, iron, and gold. Historical production of antimony, arsenic, beryllium, bismuth, cadmium, copper, fluorite, gold, halloysite clay, iron, lead, manganese, molybdenum, silver, tungsten, zinc; current production of beryllium, fluorite, and gold. |
| Production |
Tintic: 19,982,708 tons at 0.142 oz/t Au, 14.26 oz/t Ag 0.64% Cu, 5.82% Pb, 1.29% Zn; some production of Sb, As, Bi, Cd, Mn, halloysite clay; Drum Mountains: Nearly 50 million lbs Mn, mainly from the Staats and Pratt mines around Mt Laird Eocene quartz monzonite porphyry stock; distal disseminated deposits produced 3.2 Mt at 1.23 ppm Au; Spor Mountain: The Yellow Chief mine produced about 400,000 lbs U3O8 between 1955 and 1968 (Pool, 2017). Materion (formerly Brush Wellman): Be mined since 1968 yielding over 16 million lbs Be(OH)2; Trout Creek: 93 t Zn-Pb-Ag ore and 7890 lbs WO3 (Krahulec, 2018b). |
| Status |
Past mining. Active Au mining at the Trixie mine with channel face sampling grades exceeding 3,000 g/t Au, active exploration for precious and base metal targets; Spor Mountain: Active mining of Be by Materion, active exploration and mining for fluorite by Ares Strategic Minerals; Drum Mountains: active exploration for Au and Cu; Fish Springs: active exploration for Cu, In, and Zn. |
| Estimated resources |
Tintic: Burgin mine Indicated and Inferred 18,517,000 oz Ag, 40,000 oz Au, 562,050,000 lbs Pb, and 204,000,000 lbs Zn; Southwest Tintic: estimated resource of 1.5 billion tons at 0.21% Cu and 0.01% Mo; Drum Mountains: Porphyry Basin (EDM) porphyry Mo-Cu deposit, estimated resources 4 Mt at 0.22% Cu (Krahulec, 2015); Spor Mountain: 8.8 million tons at 0.248% Be Proven and Probable reserves estimated by Materion to be enough for 75 years mine life at current (2020) production levels; Fish Springs: Indicated and Inferred sulfide plus oxide resource totaling over 66 million tonnes including 1.3 million tonnes Zn, 140,000 tonnes Cu, 1.6 million kg In and 19.5 million tonnes Fe (Dyer and others, 2014). |
| Geologic maps |
Majority of the belt is covered by 1:24,000 scale mapping with significant exceptions in the core of the Tintic districts and over Spor Mountain and Drum Mountains. |
| Geophysical data |
Inadequate Rank 4 aeromagnetic coverage. |
| Favorable rocks and structures |
The Tintic-Deep Creek mineral belt is an east-trending zone of aeromagnetic anomalies, with two generations of magmatism, and associated mineralization. Igneous rocks are emplaced into a predominately Paleozoic basement that has experienced multiple episodes of compressional deformation and structural dismemberment. Limestone and dolomite constitute more than half the Paleozoic rocks, followed by quartzite and sandstone, and shale is least abundant. Igneous rocks include a late Eocene suite of calc-alkaline volcanic and intrusive rocks, such as the Ibapah stock in the Deep Creek Mountains. A later bimodal suite of basalts and highly evolved high silica topaz rhyolites (such as seen in the Thomas Range) occurs from the early Miocene (Rowley, 1998; Zimbelman and others, 1988; Stoeser, 1993). Within the Tintic-Deep Creek belt is the Beryllium Belt (Cohenour, 1963; Mills and Rupke, 2020), extending from the Sheeprock granite in the east to the Ibapah stock in the west. |
| Deposits |
Brush Wellman, Spor Mountain (MRDS dep_id: 10400503), Yellow Chief, Staats, Pratt, Copperhead, Black Jack, Black Diamond, Last Chance, Gemini, Mammoth-Chief, Plutus, Godiva, and Iron Blossom, Trixie, Burgin, Swansea, West Desert (Crypto) Zn-In-Cu skarn. |
| Evidence from mineral occurrences |
MRDS; UMOS (Utah Geological Survey, 2021). |
| Geochemical evidence |
Spor Mountain: Beryllium mineralization is associated with Mn and is enriched in other lithophile elements such as F, U, Li, and the rare earth elements (REE) Ce, Dy, Er, Gd, Ho, Nd, Sm, Y, and Yb. Published geochemical data for whole rocks showing relatively high values of Li and presence of Li-bearing clay minerals. Drum Mountains: Largest producer of Mn in Utah; minor Bi production; Cu-Au-Ag ores anomalous in As, Bi, Sb, Sn, Te; distal disseminated gold ore weakly anomalous in As, Bi, Sb (Lovering and McCarthy, 1978; Zimbelman and others, 1991; Krahulec, 2011b, 2015). Tintic: Tetrahedrite-tenantite (Sb, As, rare Cu-tellurates (Te). Fish Springs: Pb-Ag vein and replacement ores in the Silurian Laketown Dolomite are strongly anomalous in As, B, Cd, Mn, Mo, V, and Zn (Krahulec, 2018b). West Desert: Mineralization consists of sphalerite with lesser chalcopyrite occurring commonly with massive magnetite in skarn and replacement bodies. Indium occurs predominantly as lattice substitution in sphalerite. |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
See Cohenour (1963), Johnson and Christiansen (2016), Rowley (1998), Krahulec (2018b). |
| Comments |
This focus area is a large regional area that covers other focus areas that are smaller and more specific to local geology and mineralization. The intention of this focus area is to show regional potential, whereas the more specific focus areas provide vectoring for known mineralization. This focus area includes significant porphyry Cu-Mo-Au and Climax type mineral systems, as well as overlaps with the Beryllium Belt. This focus area includes the prolific greater Tintic area, the world-leading Spor Mountain Be district, and Utah's largest Mn producing district (Drum Mountains). It also includes the only established resource of In in the United States in the Fish Springs district. |
| Cover thickness and description |
Variable. |
| Authors |
Stephanie Mills. |
| New data needs |
Regional aeromagnetics survey to create a regional interpretation of major structural, igneous, geophysical, and mineral trend; geologic mapping; modern geochronology to better identify magmatic evolution and overprinting mineral potential. |
| Geologic mapping and modeling needs |
1:24,000 mapping over the central Tintic area, Spor Mountain, and Drum Mountains. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and radiometric surveys. |
| Digital elevation data needs |
High-resolution lidar to define mine waste and tailings under reclamation for examination of mining waste potential. |
