MAPPING MINERAL SYSTEMS AND CRITICAL MINERAL RESOURCE PROSPECTIVITY ACROSS ALASKA

Alaska’s geologic framework hosts numerous mineral systems over large regions that form in a wide variety of geotectonic environments. These systems exhibit considerable spatial and temporal complexity and may have evolved and (or) been overprinted, deformed, displaced, or otherwise disrupted during and after they were incorporated into the Alaska accretionary tectonic collage. The mapping of mineral systems and their host geologic terranes provides essential insights into the potential for formation, localization, and distribution of ore deposits and associated critical mineral enrichments. In Alaska, we mapped the approximate distribution of 17 mineral systems. Globally, similar mineral systems are known to contain primary or byproduct critical mineral enrichments, and those recognized in Alaska have known or suspected potential to host 22 of the 35 critical mineral commodities as presently defined. Our mapping was guided by statewide, publicly available geologic, geochemical, geophysical, and mineral occurrence datasets. Recent U.S. Geological Survey mineral resource prospectivity models for Alaska show qualitative analyses of mineral resource potential across continuous regions and provided additional guidance for evaluating the footprints of mineral systems. The mineral systems and related prospectivity maps were combined to delineate more than 100 focus areas that have critical mineral resource potential in the state. We further analyzed the spatial overlap between focus areas to identify regions where the diversity of mineral systems and possible critical mineral enrichments were greatest. The region with the greatest overlap—the Yukon-Tanana upland, eastern interior AK—was selected as the first priority for new geophysical, geochemical, and geological data collection under the USGS Earth Mapping Resources Initiative. Other regions of interest such as the Kuskokwim Mountains and Seward Peninsula in southwestern and western Alaska, respectively, will be the focus of new data collection in the future. Our mapping of mineral systems, critical mineral prospectivity, and the resulting focus areas provide a strategic framework for prioritizing new research and data collection in Alaska to advance our understanding of domestic critical mineral potential.