Eagle Mountains fluorite

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

Information leading to the delineation of this focus area

Basis for focus area The Eagle Mountains fluorite deposits occur as carbonate replacement deposits in fissures. Mineralization mainly occurs on the eastern side of the Eagle Mountains and includes limestone replacement bodies and fissures that cut Oligocene-Miocene volcanic rocks. Focus area approximately outlines extent of carbonate units and the eastern portion of volcanic rocks.
Identified resources Identified fluorite resource; historical production of fluorite.
Production 12,000 tons of fluorite produced in 1940s (Gillerman, 1953).
Status Past mining.
Estimated resources Estimated 100,000 tons of 30% CaF2 for the entire Eagle Mountains fluorspar district (Gillerman, 1953).
Geologic maps Gillerman (1953), scale 1:24,000.
Geophysical data Inadequate Rank 4 aeromagnetic and Rank 5 aeroradiometric coverage.
Favorable rocks and structures Replacement orebodies and veins near rhyolite and limestone contacts in eastern part of the mountain range. The major fluorspar deposits of the Eagle Mountains can be classified in three large groups on the basis, primarily, of the structural conditions that governed their emplacement: 1) fissure veins associated with east-trending faults, 2) fissure veins associated with northeast-trending faults, and 3) bedding-replacement deposits (Gillerman, 1953). Polymetallic sulfide mineralization hosted in veins is locally associated with the Eagle Mountain caldera ring fracture (Henry and Price, 1984).
Deposits Spar Valley (MRDS dep_id: 10100557), Eagle Spring mine (MRDS dep_id: 10085683).
Evidence from mineral occurrences MRDS.
Geochemical evidence Unknown.
Geophysical evidence No data known.
Evidence from other sources No data.
Comments Lead, Zn, and Ag mineralization reported along Eagle Mountain caldera margin. Antimony, As, Ga, Ge, In, and Mn are inferred from the mineral system/deposit type table (Hofstra and Kreiner, 2020).
Cover thickness and description Mostly exposed.
Authors Joshua M. Rosera.
New data needs Aeromagnetic coverage needed to help map structures. Aeroradiometric coverage needed to map rhyolitic units that appear to be spatially associated with mineralization.
Geologic mapping and modeling needs Eagle Mountains NE 1:24,000 scale quadrangle for lithology, alteration, and mineralization.
Geophysical survey and modeling needs High resolution, Rank 1 aeromagnetics and aeroradiometric coverage.
Digital elevation data needs Lidar complete.