CRITICAL MINERAL POTENTIAL OF THE NORTH-CENTRAL UNITED STATES

The North-Central United States hosts significant concentrations of mineral resources containing barite, cobalt, fluorspar, germanium, graphite, manganese, nickel, niobium, platinum group elements, potash, rare earth elements (REE), scandium, titanium, vanadium, and zinc, which all are critical for the Nation’s economic and national security. Through a multi-year effort, the USGS-led Earth Mapping Resources Initiative (EMRI) and partner State geological surveys have identified 65 focus areas in the North-Central United States with known or potential to host critical minerals. Focus areas, categorized by mineral system (geologic factors that control and generate the preservation of mineral deposits) and specific deposit types, include active mines, historical mining districts, new exploration projects, and areas with favorable geologic characteristics. Delineated focus areas are guiding acquisition of new geophysical, geochemical, and geologic map data that are being used to further assess domestic critical mineral resource potential in prospective areas. Focus areas in the North-Central United States with identified critical mineral resources include: 1) barite and zinc in the Upper Mississippi Valley mineral district of Illinois, Iowa, and Wisconsin; 2) fluorspar in the Illinois-Kentucky Fluorspar District; 3) manganese in iron-formation of the Cuyuna Range in Minnesota; 4) cobalt, nickel, titanium, and vanadium in mafic magmatic rocks of the Midcontinent Rift System in Michigan, Minnesota and Wisconsin, which includes the only active domestic nickel mine; 5) zinc in the massive sulfide deposits in the Pembine-Wausau terrane, Wisconsin; 6) niobium, scandium, and titanium in the Elk Creek carbonatite in Nebraska; and 7) cobalt, nickel, and zinc in the Mississippi Valley type (MVT) mineral districts of Missouri. EMRI is also investigating the potential of unconventional host rocks for critical minerals, such as REE, vanadium, and yttrium in sedimentary black shale phosphorites in Illinois, Indiana, Iowa, Michigan, Minnesota, Wisconsin, and Ohio. A new initiative for EMRI is evaluating the feasibility of extracting byproduct critical mineral commodities from mine tailings in historical mining districts, such as germanium and indium from MVT deposits.