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 included here; This deposit type includes volcanogenic massive sulfide deposits units in the Black Hills, Hartville Uplift and at 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 copper, gold, and iron.
Production Unknown.
Status Past mining.
Estimated resources Unknown.
Geologic maps Harris and others (1985), scale 1:500,000; Love and Christiansen (1985), scale 1:500,000; Mineral system-specific maps include: Wind Rivers/South Pass: Hausel (1991), scale 1:48,000; Houston and others (1992), scale 1:1,000,000; Scott and Sutherland (2009), scale 1:100,000; Sutherland and Hausel (2006), scale 1:100,000); Hartville Uplift: Day and others (1999), scale 1;24,000; Houston and others (1992), scale 1:1,000,000; McLaughlin and Harris (2005), scale 1:100,000; McLaughlin and others (2011), scale 1:100,000; Sims and Day (1999), scale 1;48:000; Sims and others (1997), scale 1:24,000; Black Hills: Sutherland (2007b), scale 1:100,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Metadacite and iron-formation at South Pass; Graphitic metapelite, cherty exhalite, and carbonate layers in muscovite schist at Hartville Uplift; hornblende schist in Black Hills.
Deposits Green Hope mine (MRDS dep_id: 10278837), Tabor Grand mine (MRDS dep_id: 10279201), Carissa mine (MRDS dep_id: 10111268), B&H Mining Company (MRDS dep_id: 10278683), Diana mine (MRDS dep_id: 10254726), Midas mine (MRDS dep_id: 10132968); Barite: Sunrise mine (MRDS dep_id: 10254298).
Evidence from mineral occurrences MRDS.
Geochemical evidence From Hausel (1988): assay of 3 volcanogenic massive sulfide samples at McCann Pass in Hartville Uplift only analyzed for Au, Ag; although no other analyses available, potential for elevated Ba and Mn in most volcanogenic massive sulfide deposits exists. From Houston and others (1992), 40 ft of "silver-rich pyrite-sphalerite massive sulfide were found by a single drill hole into a deeply buried sulfide body." From Sutherland and others (2018): elevated Sb concentrations (at least 5 times crustal abundance) in the Hartville Uplift Whalen Group.
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 could be a game-changer. Could use new 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.