Wyoming Metasedimentary and Metavolcanic Belts

Region West, Rocky Mountains
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Precambrian mafic/ultramafic metasedimentary and metavolcanic belts, associated dike, sill, vein, and pegmatite complexes, and derived placers – all with similar depositional and metamorphic histories not included within other focus areas are included here; This area deposit type includes metasedimentary/metavolcanic units and associated intrusives in the southern Laramie Range and South Pass. With the exception of the somewhat better-understood South Pass greenstone belt, these metasedimentary and metavolcanic rocks have generally poorly constrained mineral potential.
Identified resources Historical production of gold and silver.
Production Unknown.
Status Past mining.
Estimated resources None.
Geologic maps Horton and others (2017), scale 1:500,000; Harris and others (1985), scale 1:500,000; Love and Christiansen (1985), scale 1:500,000; Some specific maps include: Wind Rivers/South Pass: Hausel (1991), scale 1:48,000; Scott and Sutherland (2009), scale 1:100,000; Sutherland and Hausel (2006), scale 1:100,000); Southern Laramie Range: Darton and others (1910), scale 1:125,000; Houston and Marlatt (1997), scale 1:24,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Felsic intrusions, metasedimentary and metavolcanic units and associated vein/pegmatite systems.
Deposits Manganese: occurrence from St Louis mine (MRDS dep_id: 10090679); Titanium: Silver Crown district (MRDS dep_id: 60000972); Tungsten: three occurrences (MRDS dep_ids: 10090608, 10090606, 10157553) and one prospect (MRDS dep_id: 10254351) at Deer Creek district, four occurrences (MRDS dep_ids: 10303403, 10090610, 10279294, 10090609), two past producers (MRDS dep_ids: 10008890, 10230223), and three prospects (MRDS dep_ids: 10181609, 10133230, 10133422) at South Pass, and one producer from Silver Crown district (MRDS dep_id: 60000972); Zinc: one producer from Silver Crown district (MRDS dep_id: 60000972).
Evidence from mineral occurrences MRDS.
Geochemical evidence Erythrite (cobalt bloom) was discovered in the vicinity of Middle Crow Creek of the Silver Crown district. Analyses of some ore in the district also showed traces of linnaeite (CO3S4)...; From Hausel (1989): "Spectrographic analyses [of Silver Crown district's Copper King (Arizona) mine ore body] also showed traces of Pb, Zn, W, and 0.5 to 3.0% Ti (Soule, 1955)." From Sutherland and others (2018): elevated Sb concentrations (at least 5 times crustal abundance) in veins and metagraywackes at South Pass and in Black Hills Mineral Hill district.
Geophysical evidence No data.
Evidence from other sources No data.
Cover thickness and description Variable, mix of good exposure to thick surficial cover and heavily forested areas.
Authors Rachel N. Toner, Patricia M. Webber, Benjamin J. Drenth.
New data needs New Rank 1 geophysics-supported and modern geochronology-supported mapping; reconnaissance geochemistry.
Geologic mapping and modeling needs Variable, but new, modern 1:24,000 scale mapping generally needed, supported by Rank 1 geophysics and modern geochronology.
Geophysical survey and modeling needs Rank 1 aeromagnetics and aeroradiometrics.
Digital elevation data needs Lidar complete in Wyoming.