New Mexico Geological Society Annual Spring Meeting — Abstracts

The rare-earth elements (REE) include a group of 15 chemically similar elements called the lanthanide group since lanthanium is the first of the series. REE are found in over 100 minerals, but significant concentrations of them are rare. Industrial applications of these elements are varied and include use in petroleum cracking catalysts, ceramics and glass, metallurgy, electrical applications, phosphors, and other minor uses.

Four types of REE deposits are recognized in New Mexico: veins and breccias, pegmatites, carbonatites, and cretaceous heavy-mineral, beach-placer deposits. The only production of REE from New Mexico has been minor from pegmatites. The most important type of deposits in New Mexico of potential economic interest is veins and breccias. The more favorable deposits are in the Laughlin Peak area, Colfax County; Gallinas Mountains, Lincoln County; and possibly Pajarito Mountain, Otero County. Other deposits occur in the state as well. Pegmatite deposits have been historically small producers of REE in New Mexico, but further production will probably be limited. REE-bearing pegmatites occur in several areas of the Sangre de Cristo, Tusas, and Burro Mountains. Carbonatites elsewhere in the world are noted for their high concentrations of REE, but the five occurrences in New Mexico are low grade and small tonnage. Heavy-mineral, beachplacer sandstone deposits are concentrations of heavy minerals that formed on beaches or in long-shore bars in a marginal-marine environment. Numerous beach-placer sandstone deposits of Cretaceous age are found in the San Juan Basin, but are low tonnage and low grade.

Several areas in New Mexico appear economically promising, but geologic mapping, sampling, and drilling of the REE deposits are required to properly assess the REE potential in the state.