Wyoming Lode

Prospect, Inactive

Commodities and mineralogy

Main commodities Au; Sb
Other commodities As; Hg
Ore minerals arsenopyrite; cinnabar; gold; stibnite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MD
Quadrangle map, 1:63,360-scale C-6
Latitude 63.574
Longitude -155.933
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Wyoming prospect is situated on a steep, north-facing spur overlooking the East Fork of Montana Creek and the Main Fork of Wyoming Creek at an elevation of 2,400 feet (731 m) in Section 22, T. 22 S., R. 15 E., of the Kateel River Meridian. The reporter investigated the prospect in 1996.

Geologic setting

Geologic description

The Wyoming Lode consists of three distinct quartz-sulfide-sulfosalt veins that strike North 65 degrees east and dip steeply to vertical. The vein swarm can be traced for about 450 feet (137 m) along the strike and have a collective width of about 200 feet (61 m). The southern-most and highest vein consists of disseminated stibnite and arsenopyrite in a quartz vein that ranges from 1 foot to 3 feet (0.3 to 0.9 m) thick. The northern-most veins, which range from 2 to 5 feet (0.6 to 1.5 m) thick, contain massive to disseminated pods of very coarse-grained, interlocking stibnite blades and euhedral quartz crystals to 9 inches (23 cm) long and uncommon arsenopyrite. Distinctly reddish kermesite, an oxidation product of stibnite, frequently covers the stibnite blades. The textural habitat of the Wyoming and Moose Jaw lode (MD019) 2 miles (3.2 km) to the southwest are quite similar, which suggests both lodes might be related (Bundtzen and others, 1997). Mertie (1936) described the Wyoming lode as a cinnabar-stibnite deposit. However, Bundtzen and others (1997) searched for but could not identify cinnabar in the vein system.
All mineralized veins at the Wyoming Lode cut hornfels adjacent to the Cripple Creek Mountains pluton, about 0.5 miles (0.8 km) from the sediment-intrusive contact. The Wyoming Lode is inferred to be Late Cretaceous based on the 71.2 Ma isotopic age of the adjacent pluton (Bundtzen and others, 1997).
Five chip-channel samples taken across three of the mineralized veins by Bundtzen and others (1997) contained up to 652 ppb gold, 2,830 ppm arsenic, and 45.7 percent antimony, but no detectable mercury.
Geologic map unit (-155.935375040441, 63.5733905025594)
Mineral deposit model Simple stibnite deposits (Cox and Singer, 1986; model 27d).
Mineral deposit model number 27d
Age of mineralization The Wyoming Lode is inferred to be Late Cretaceous based on the 71.2 Ma isotopic age of the adjacent pluton (Bundtzen and others, 1997).
Alteration of deposit Stibnite oxidized to kermesite.

Production and reserves

Workings or exploration Surface pits and trenches have been excavated to explore the deposit. Five chip-channel samples collected by Bundtzen and others (1997) contain up to 652 ppb gold, 2,830 ppm arsenic, and 45.7 percent antimony. None of the samples contained detectable mercury.
Indication of production None
Reserve estimates None.
Production notes Very coarse stibnite blades have possible mineral specimen quality potential.

Additional comments

See Moose Jaw Lode (MD019).

References