IDENTIFICATION OF AREAS WITH CRITICAL MINERALS RESOURCE POTENTIAL IN SIX GROUPS OF MINERAL DEPOSIT TYPES IN ALASKA

Alaska has considerable potential for undiscovered resources of critical minerals. We present recently completed estimates of mineral resource potential and certainty for six groups of mineral deposit types: (1) rare earth element (REE) ± Th, Y, Nb, and Zr, associated with peralkaline to carbonatitic intrusive rocks; (2) placer and paleoplacer Au deposits ± platinum group elements (PGE), Cr, Sn, W, Ag, or Ti; (3) PGE deposits ± Co, Cr, Ni, Ti, and V, associated with mafic to ultramafic intrusive rocks; (4) carbonate-hosted Cu deposits with Ag, ± Co, Ge, and Ga; (5) sandstone-hosted U deposits ± V or Cu; and (6) Sn-W-Mo deposits, ± In, ± fluorspar associated with tin-specialized granites.

Statewide datasets were selected and scored based on their relevance for a specific deposit group, area covered, and importance for identifying mineral concentrations. High, medium, or low potential scores and certainty values were estimated using the areas of 12-digit hydrologic units as the spatial classification unit. Assignment of resource potential for specific deposit groups was determined based on scoring criteria; certainty values were based on the number of datasets contributing to the potential score.

Results are shown on maps keyed with the HUC-scale mineral resource potential for each deposit group. Noteworthy areas of potential are: 1) western and northern Alaska Range, Yukon-Tanana uplands, and known areas in the Darby-Hogatza, Kokrines-Hodzana, and southeast Alaska igneous belts, and Tofty-White Mountains for both REE-bearing peralkaline to carbonatitic intrusive rocks and tin-specialized granites, 2) southwestern Alaska and the Alaska Range for placer Au, in addition to known districts, 3) Yukon-Tanana uplands and known areas in the Brooks Range, Goodnews Bay, Kokrines-Hodzana belt, Alaska Range, Chugach Mountains, Kenai Peninsula, and southeastern Alaska for PGE-bearing deposits associated with mafic to ultramafic intrusive rocks, 4) Seward Peninsula, the western and northern Alaska Range, Yukon-Tanana uplands, and southeastern Alaska, and known areas in the southern Brooks Range and Wrangell Mountains for carbonate-hosted Cu, and 5) Kokrines-Hodzana belt, Yukon-Tanana uplands, and western and northern Alaska Range, and known areas of the Darby-Hogatza igneous belt for sandstone U.