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 Identified hafnium, lithium, niobium, REE, thorium, tin, and uranium resource; historical production of barite, copper, fluorite, gold, lead, REE, silver, and tungsten.
Production Wind Mountain (Cornudas Mountains): Test shipments of nepheline syenite; Round Top: Gold, Ag, Cu, Pb, W, REE, and fluorite produced in some districts in New Mexico, fluorite production in Texas; Gallinas Mountains Mining District: Barite: minor production; Fluorite: approximately 1000 tons produced at Red Cloud; total fluorite from district 2,400 tons.
Status Past mining. Wind Mountain (Cornudas Mountains): Past exploration for nepheline syenite and REE. Round Top: Current and recent exploration as a heavy REE, Sn, U, Be prospect, drilled and analyzed, but never mined; adjacent Sierra Blanca Mountain is being mined for rhyolite road and rail material. Gallinas Mountains Mining District: Past drilling with active claims.
Estimated resources Wind Mountain (Cornudas Mountains): Round Top: As of 2014, Measured, Indicated and Inferred resources: 82,165,000 metric tons of ore containing tantalum, thorium, REE, niobium, hafnium, tin, and uranium at 428 g/t Y equivalent. They also estimated a lithium resource from column test at 400+ ppm Li. Gallinas Mountains Mining District: 537,000 short tons of 2.95% total REE (not NI 43-101 compliant; Schreiner, 1993).
Geologic maps Horton and others (2017), scale 1:500,000.
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 Nepheline syenites; Rhyolite domes or laccoliths.
Deposits Wind Mountains prospect (MRDS dep_id: 10125858), Round Top prospects (MRDS dep_id: 10085039; USMIN Site_ID: TX00005), All American Prospect (MRDS dep_id; 10150332), Conqueror mine (MRDS deo_id: 10101830), Red Cloud (MRDS dep_id: 10150086).
Evidence from mineral occurrences MRDS; USMIN.
Geochemical evidence Chemical analyses of Round Top are in Elliott (2018). Grab samples from the Conqueror fluorite mine have 18% fluorite and 6.2% barite (McLemore, 2010c).
Geophysical evidence Recent Rank 1 aeromagnetic and aeroradiometric data over part of the region (Bultman, 2021).
Evidence from other sources Mining permits in specific areas.
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).