Big Bend alkaline rocks

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 in the Big Bend area. Fluorite associated with carbonate-replacement mineralization near intrusions.
Identified resources Historical production of fluorite.
Production Paisano mine produced < 30,000 tons of fluorite (1971-1986).
Status Past mining.
Estimated resources Resources at Paisano mine are 9,000,000 t of ore @ 79.6% CaF2.
Geologic maps Cameron, Cameron and Carman (1986), scale 1:487,000. Henry and others (1989), scale 1:24,000.
Geophysical data Partly adequate (50%) aeromagnetic coverage over focus area and adequate aeroradiometric coverage.
Favorable rocks and structures Contacts between carbonate and peralkaline intrusions.
Deposits Paisano mine (MRDS dep_ids: 10085608, 10300188), Burney mine (MRDS dep_id: 10085729).
Evidence from mineral occurrences MRDS.
Geochemical evidence Multi-colored fluorite (purple, black, gray, green, white) occurs as fine-grained masses in limestone with calcite, pyrite, and quartz. Fluorite mineralization can be accompanied by molybdenite and cinnabar. Fluorite also associated with enrichment of U, Th, Mo, Be, Ba, As and Pb.
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Cover thickness and description Fluorite replacement deposit potential at depth depending on relationship to unexposed intrusions and permeable structures.
Authors Brent A. Elliott, Joshua M. Rosera.
New data needs Geologic mapping, geophysics.
Geologic mapping and modeling needs Detailed geologic mapping.
Geophysical survey and modeling needs High resolution, Rank 1 aeromagnetics and aeroradiometric coverage.
Digital elevation data needs Lidar complete.