Systems Approach to Critical Minerals Inventory, Research, and Assessment

Science Issue and Relevance

Critical minerals are mineral commodities that are mostly or entirely imported because of inadequate or uneconomic domestic sources. Many critical minerals are susceptible to supply disruptions that could comprise national defense, transportation, and communications systems. Recent Executive and Interior Secretary Orders request that the USGS identify domestic sources of critical minerals.

Critical minerals occur in a wide variety of deposit types that form within larger mineral systems of different types, ages, that occur in different parts of the country. They range from commodities that are the principal mined product to recovery as by-products during processing of other metallic ores. Identification of domestic sources of critical minerals requires thorough examination of numerous mineral systems and deposits types, and quantification of potentially recoverable critical minerals in mined deposits. The Earth Mapping Resources Initiative (Earth MRI) requires information on areas with high critical mineral potential to prioritize areas for geophysical surveys and geological mapping. A systems approach for defining Earth MRI focus areas must be developed that relates critical minerals to the deposit types and mineral systems they occur in.

Methods to Address Issue

Project Goals are the following:

• Earth Mapping Resources Initiative (EarthMRI) support: Develop a mineral systems approach for defining focus areas.
• Inventory: Gather and generate data on the abundance of critical minerals in ore, minerals, and processed materials.
• Research: Identify the sources and controls of critical mineral accumulation in mineral systems, and incorporate the critical minerals into updated genetic and assessment models.
• Assessment: Conduct critical mineral assessments of mineral systems of interest.

Project activities:

Database and Geostatistics: develop a database on the location and concentrations of critical minerals in rocks and minerals classified by system and deposit type to evaluate their potential to be produced as co- or by-products.

Geochemistry of Rocks and Minerals: the concentration of critical minerals in rocks and minerals from large mineralizing systems is not well known. Evaluate the Historic Ores Collection to determine the concentration of critical minerals and classify the results by system and deposit type.

Geochronology, Isotopes, Fluid Inclusions: conduct research on the ages, sources, and physicochemical processes that concentrate critical minerals in large mineralizing systems.

Inventory, Research, and Assessment of Critical Minerals in the Following Systems:

• Surficial Weathering Systems: laterite and placer deposits with additional research in Arkansas bauxite deposits.
• Lacustrine Systems: evaporite, brine, and clay deposits.
• Epicontinental Marine Basin Systems: sedimentary exhalative (sedex), Mississippi Valley Type (MVT), sedimentary copper, iron-manganese oxide, phosphate, barium-strontium sulfate, and black shale deposits.
• Volcanogenic Submarine Hydrothermal Systems: volcanogenic massive sulfide (VMS) and manganese oxide deposits.
• Metamorphic Shear Zone Hydrothermal Systems: orogenic gold and Coeur d'Alene polymetallic sulfide deposits.
• Subduction-related Magmatic Hydrothermal Systems: pegmatite, greisen, porphyry, skarn, replacement, vein, epithermal, and volcanogenic deposits.
• Rift-related Magmatic Hydrothermal Systems: pegmatite, greisen, porphyry, skarn, replacement, vein, epithermal, and volcanogenic deposits.
• Iron Oxide Apatite (IOA)-Iron-Oxide-Copper-Gold (IOCG) Systems: IOA, IOCG, and related deposits.
• Carbonatites and Peralkaline Magmatic Systems: intrusion-related rare earth element deposits with additional research on Hicks Dome, KY, and Bokan Mountain and Dora Bay, AK.
• Mafic Magmatic Systems: magmatic sulfide-rich nickel-copper±platinum-group element (PGE), Fe-Ti-V, and Cr deposits related to mafic/ultramafic intrusions.

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