New Mexico Proterozoic alkaline rocks and pegmatites

Region West, Southwest
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Pegmatites, veins, and replacements associated with Proterozoic rocks in mineral districts and areas as outlined in USMIN and modified from McLemore and Austin (2017, fig.1): includes Picuris, El Porvenir, Elk Mountain-Spring Mountain, Rociada, Tecolote, Nambe, La Cueva, Hopewill, Petaca Bromide No. 2, and Tijeras Canyon areas of north-central New Mexico and the Black Hawk, Burro Mountains, White Signal, and Gold Hill districts of southwestern New Mexico. Also included are the Picuris District (Harding Pegmatite) in New Mexico.
Identified resources Historical production of beryllium (beryl), lithium, niobium, REE, and tantalum.
Production Beryllium: Harding mine in Taos county was a leading producer of beryl in the mid-20th century (848 tons of beryl; Schilling, 1960). Various small beryl producers (a few tons total) in Rio Arriba including the Persimmon Peak-Las Tablas group (Jahns, 1946). Total beryl production from pegmatites in New Mexico was 1,739,817 lbs (McLemore, 2010d). REE-Nb-Ta: Petaca district: 1940s-50s; 112 lbs samarskite, few 100 lbs monazite, 12,000 lbs Ta-Nb-REE ore (McLemore and others, 1988a). Several pegmatites produced book mica beginning in 1870 and continuing intermittently until 1944 (Bingler, 1968). About $10,000 worth of beryl, tantalite-columbite and monazite from pegmatites (Tecolate; Redmon, 1961); 500 lbs Ta-U-REE concentrate from pegmatites (Elk Mountain-Spring Mountain; Jahns, 1946; Holmquist, 1946). Small production form the White Signal district in the 1950s.
Status Past mining. Active mining claims and surface sampling by several companies and individuals in Petaca and Rocida districts.
Estimated resources Unknown.
Geologic maps Bingler (1965), scale 1:24,000; Gillerman (1954), scale 1:12,000; Green and Jones (1997), scale 1:500,000; Hedlund (1978a), scale 1:24,000; Gaynor (2013), various scales.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Thorium- and rare earth elements (REE)−bearing pegmatites crop out in Precambrian rocks in the southeastern Tusas Mountains (Bingler, 1968). Pegmatites of the Petaca district take a variety of shapes, such as dikes, sills, pipes, pods, troughs, and irregular forms. Pegmatites crop out for 75 to 1,430 ft (23 to 436 m) in length (an average outcrop length is 410 ft (125 m), with an average width of 30 to 35 ft (9 to 11 m) (Bingler, 1968). Beryllium also associated with pegmatites.
Deposits La Jarita-Apache Group (MRDS dep_id: 10014278), North Cribbenville mine (MRDS dep_id: 10101881), New Cribbenville mine (MRDS dep_id: 10087941), Alamos (Parker) mine (MRDS dep_id: 10097879), Globe mine (MRDS dep_id: 10014266), Harding Pegmatite (MRDS dep_id: 10009174), Persimmon Peak-Las Tablas Group (MRDS dep_id: 10014276), Petaca District (USMIN Site_ID: NM00029), El Porvenier District (USMIN Site_ID: NM00025).
Evidence from mineral occurrences MRDS; USMIN; geologic mapping and sampling.
Geochemical evidence Elevated REE concentrations in Petaca district pegmatites mainly reflect the mineral samarskite. Monazite and apatite are also known. Sampling reported in McLemore and others (1988b) suggests that pegmatites of the district average about 0.04% Nb. A selected sample of Globe pegmatite had 10,332 ppm Th. Another had 600 ppm Y, 600 ppm Yb, 396 ppm Er, 186 ppm Gd, and 3117 ppm TREE+Y. See Spilde and others (2011).
Geophysical evidence Inadequate aeromagnetic coverage.
Evidence from other sources Not known; U.S. Geological Survey and others (1980).
Comments Samarskite, ferrocolumbite, and monazite in the pegmatites (all with high ΣHREE) are mainly associated with albitization and the formation of cleavelandite masses from earlier quartz-microcline pegmatite, although all ΣHREE also occur as isolated crystals in the Globe pegmatite (Jahns, 1946; Wright, 1948). Small companies/prospectors have active claims, mapping varies. Harding mine now owned and operated by the University of New Mexico.
Cover thickness and description Pegmatites crop out in Proterozoic crystalline rocks that stand generally higher than partially covering Tertiary and Quaternary epiclastic and volcanic cover that extends generally to the east.
Authors Lukas Zurcher, Timothy S. Hayes, Mark E. Gettings, Virginia T. McLemore, Joshua M. Rosera.
New data needs Detailed mapping in Sangre de Cristo pegmatites, geochemistry and mineralogy.
Geologic mapping and modeling needs Detailed geology-structure-alteration-mineralization mapping.
Geophysical survey and modeling needs High resolution geophysical coverage needed.
Digital elevation data needs Lidar complete for most subregions in this focus area.