Reduced intrusion-related

Reduced intrusion-related systems form in continental magmatic arcs by similar processes from fluids exsolved from calc-alkaline plutons and stocks that assimilated carbonaceous pyritic country rocks. Resulting ore deposits tend to be poor in Cu, Mo, Sn and enriched in W, Au, Ag, Te, Bi, Sb and As.
Color on map:

Deposit types

Name Commodities Critical minerals
Pegmatite LCT Li-Cs-Ta Li, Cs, Ta, Nb, Sn, Be, Cs
Gold Au, Ag Te, Bi, Sb, As
Greisen-V tungsten W, Mo W, Mo
Skarn copper-molybdenum-tungsten W, Mo, Cu, Au, Ag W, Te, Bi, Re
Polymetallic sulfide S-R-V-IS Au, Ag, Pb, Zn, Cu Mn, Ge, Ga, In, Bi, Sb, As
Distal disseminated silver-gold Ag, Au Te, Bi, Sb, As
Intermediate sulfidation Au, Ag, Pb, Zn, Cu Mn, Ge, Ga, In, Bi, Sb, As
Intermediate sulfidation antimony Sb Sb
Graphite Graphite (lump) Graphite (lump)

References


Source: Hofstra, A.H., and Kreiner, D.C., 2020, Systems-Deposits-Commodities-Critical Minerals Table for the Earth Mapping Resources Initiative: U.S. Geological Survey Open-File Report 2020-1042, 24 p., https://doi.org/10.3133/ofr20201042.

List of Earth MRI focus areas with mineral system = Reduced intrusion-related

14 focus areas match these criteria.

Focus area Region States Mineral Systems Deposit types Commodities
Alaska Peninsula-Aleutian Range Gold Alaska Alaska Reduced intrusion-related Gold gold; silver
Central Alaska-Seward Peninsula Gold Alaska Alaska Reduced intrusion-related Gold gold; silver
Chugach Range Gold Alaska Alaska Reduced intrusion-related Gold gold; silver
Eastern Alaska Range-Talkeetna Mountains Gold Alaska Alaska Reduced intrusion-related Gold gold; silver
Eastern Brooks Range-Old Crow Gold Alaska Alaska Reduced intrusion-related Gold gold; silver
Kuskokwim Mountains Gold Alaska Alaska Reduced intrusion-related Gold gold; silver
Western Alaska Range Gold Alaska Alaska Reduced intrusion-related Gold gold; silver
Yukon-Tanana Upland Gold Alaska Alaska Reduced intrusion-related Gold; Skarn copper-molybdenum-tungsten copper; gold; molybdenum; silver
Shawangunk Mountains Area Northeast New York Reduced intrusion-related Polymetallic sulfide S-R-V-IS copper; gold; lead; silver
Big Iron Northwest Washington Reduced intrusion-related Skarn copper-molybdenum-tungsten copper; gold; iron; molybdenum; silver
Latah County beryllium Northwest Idaho Reduced intrusion-related Pegmatite LCT (none)
Orogrande Mining District Northwest Idaho Reduced intrusion-related Skarn copper-molybdenum-tungsten copper; gold; molybdenum; silver
Bald Mountain mineral district Southwest Nevada Reduced intrusion-related Skarn copper-molybdenum-tungsten copper; gold; molybdenum; silver
Buffalo Canyon Southwest Nevada Reduced intrusion-related Gold; Greisen-V tungsten gold; molybdenum; silver