Alaska Critical Minerals Cooperative

Science Center Objects

The project developed means to use several large legacy digital databases together in GIS to identify areas with mineral resource potential for critical minerals in Alaska.

Scientific Issue and Relevance

Alaska's geographic separation and complex tectonic history provide it with a geology unique within the Nation. As a result, it contains mineral resources not common in other parts of the United States, including known or potential occurrences of many of the strategic and critical elements that are vital to national defense, renewable-energy, and emerging electronics technologies. Both geologic mapping and geochemical analyses indicate Alaska has high potential for strategic and critical elements such as thorium, niobium, tantalum, indium, gallium, germanium, rare-earth elements, platinum-group metals, tin, manganese, titanium, and vanadium, and assessing these resources will require not only identifying high-potential regions, but also understanding the nature of the mineralization. Knowing where and how these elements occur will allow industry and policy makers in Alaska to focus future land-use decisions and exploration efforts in areas of most immediate impact to national defense and security.

Estimated potential for rare earth element (REE) deposits in watersheds across northern Alaska

Estimated potential for rare earth element (REE) deposits in watersheds across the BLM Central Yukon Planning Area and surrounding regions, northern Alaska. From USGS Open-File Report 2015-1021.

(USGS. Public Domain)

Methods to Address Issue

USGS and Alaska State scientists used their expertise in geologic mapping, geochemistry, and economic geology to delineate regions of Alaska with the highest potential for strategic and critical elements.

Statewide Data Evaluation: Statewide databases pertaining to geology, geochemistry, mineral occurrences, and geochronology provided the primary basis for evaluating mineral terranes and strategic and critical element potential throughout Alaska. Maps derived from these databases showed the areal distribution of certain elements and delineated areas of anomalous strategic and critical element concentrations. This allowed the creation of mineral deposit models that are consistent with the regional geology. The USGS worked with the Bureau of Land Management (BLM) to incorporate this data into the Mineral Resources chapters of the BLM's areal Resource Management Plans. In addition to indicating areas of highest strategic and critical element potential, the maps also defined areas where baseline data is inadequate for such evaluations, indicating the need for follow-up investigations.

Evaluation of SCE Potential in Certain Rock Types: Much of the research required to evaluate strategic and critical element potential is dependent on understanding the characteristics of the mineral deposits which host strategic and critical elements and the geologic structures and features that control their distribution across Alaska. Two high-priority geologic settings with significant strategic and critical element potential are alkaline intrusive rocks (for uranium and thorium) and ultramafic intrusions (for platinum-group metals). Research focused on delineating belts of these igneous rocks types; evaluating their tectonic, structural and geologic settings; identifying their mineralogy, petrochemistry, and associated lithologies; and determining which ages, suites, and tectonic settings are most likely to host elevated concentrations of strategic and critical elements.

Assessment of Alaska State Lands for Strategic and Critical Minerals: The State of Alaska is currently conducting a 3—5 year evaluation of strategic and critical element potential on State-owned lands. By having a broader, statewide geologic perspective, USGS scientists provided expertise in regional mapping, tectonic syntheses, and economic geology to this effort. Under a Letter of Agreement between the State and the USGS, State-collected data was integrated into USGS databases, and USGS samples from State lands were re-analyzed for pertinent elements. Cooperation in field programs and the collection of airborne geophysical data was also planned for this and other USGS Alaska projects.