Texas-New Mexico alkaline belt

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

Information leading to the delineation of this focus area

Basis for focus area Alkaline/peralkaline igneous rocks. The focus area includes the Trans-Pecos alkaline belt in Texas, extending into New Mexico.
Identified resources Historical production of copper, gold, iron, silver, tungsten, and zinc. Identified copper, molybdenum, niobium, and tungsten resource.
Production None.
Status Past mining. Cave Peak deposit drilled and analyzed as a Mo prospect, but never mined.
Estimated resources Cave Peak deposit reserve (1970): 100 million st with 0.09% Mo; Main Pipe reported reserve (1981): 30.892 million st with 0.13% Mo, 0.05% Cu, and 0.01% W (35% of ore is oxide) at a cut-off-grade of 0.06% Mo (possible Ag, Be, Nb, Sn byproducts); Ore breakdown given as 2 million st oxide ore with 0.272% Mo and 0.1% Nb2O5 (Long, 1992).
Geologic maps Horton and others (2017), scale 1:500,000; numerous geologic maps cover portions of areas in New Mexico; O'Neill and Nutt (1998), scale 1:24,000; Rawling and Koning (2011), scale 1:24,000; Staatz (1986, 1987), scale 1:24,000; Schmidt and Craddock (1962), scale 1:24,000.
Geophysical data Recent high resolution geophysical coverage over Trans-Pecos areas in Texas and Cornudas Mountains in New Mexico. Inadequate aeromagnetic and aeroradiometric coverage elsewhere.
Favorable rocks and structures Silicic intrusions similar to other Climax-type porphyries, but more alkalic.
Deposits Cave Peak molybdenum deposit (MRDS dep_id: 10178355; USMIN Site_IDs: TX00002; TX00010).
Evidence from mineral occurrences MRDS; USMIN.
Geochemical evidence Silicic melt inclusions at Cave Peak contain 9 to 38 ppm W, fluid inclusions contain 7 to 80 ppm W (Audétat, 2010). See McLemore (2022).
Geophysical evidence Recent Rank 1 aeromagnetic and aeroradiometric data over part of the region (Bultman, 2021).
Evidence from other sources Cave Peak porphyry Mo-(Nb) deposit is genetically related to a mafic, alkaline intrusion (Audétat, 2010; Urguhan, 2018).
Cover thickness and description Deposits may be present at depth in mapped sedimentary rocks or concealed by Cenozoic basin fill.
Authors Brent A. Elliott, Virginia T. McLemore, Joshua M. Rosera.
New data needs Alteration mapping, detailed mapping of the plutons and dikes in terms of lithology, geochemistry and mineralogy of the veins; geophysics.
Geologic mapping and modeling needs Detailed mapping needed in many areas.
Geophysical survey and modeling needs High resolution aeromagnetic and aeroradiometric survey over areas without Rank 1 data.
Digital elevation data needs Lidar complete (Texas) or in progress (parts of New Mexico).