Pikes Peak, St. Peter’s Dome (Proterozoic)

Region West, Rocky Mountains
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Pegmatites in the southern part of the Pikes Peak Intrusive Center. Some of the base and precious metal mineralization could be associated with a younger (Oligocene) alkalic porphyry (for example, the Oligocene-age St Peters dome district).
Identified resources Identified resources of fluorite; historical production of fluorite.
Production Approximately 16,100 tons of fluorite produced from the district in the 1940s, but it is not clear how much of that is associated with potentially younger alkalic porphyry-related deposits.
Status Past mining.
Estimated resources 145,000 tons of approximately 35% CaF2 Indicated + Inferred. Other references indicate greater than 65,000 tons containing a minimum of 35% CaF2 (Brady, 1975).
Geologic maps Trimble and Machette (1979), scale 1:100,000; Keller and others (2003), scale 1:24,000.
Geophysical data Inadequate Rank 5 aeromagnetic and Rank 3 aeroradiometric coverage.
Favorable rocks and structures Mount Rosa Complex in the Pikes Peak granite, syenite, pegmatite, granite.
Deposits Pikes Peak, Cheyenne district (St. Peters Dome district; MRDS dep_id: 10013843), Comanche Group, Crystal Park Area, Stove Mountain mineral locality.
Evidence from mineral occurrences MRDS.
Geochemical evidence Beryllium minerals include bertrandite, danalite, genthelvite, and gadolinite associated with accessory bastnaesite, xenotime, fluocerite, columbite, ilmenite, zircon and fluorite.
Geophysical evidence A regional magnetic low with subtle circular patterns indicating more magnetic material corresponds to the Pikes Peak intrusion. The focus area is at the edge of the low. The patterns may be variations in petrology of the granite or younger intrusions. The possible association is intriguing, but needs more research.
Evidence from other sources Unknown.
Comments Fluorite deposits are spatially associated with alkalic porphyries comparable to those from nearby Cripple Creek district (Steven, 1949; Wallace, 2010). However, the host Pikes Peak granite also contains cryolite and could potentially be a magmatic source for fluorite. More work is needed to distinguish between potential mineral systems in this focus area. Presence of some critical commodities, such as U and Sn, are inferred based from the mineral system/deposit type table (Hofstra and Kreiner, 2020).
Cover thickness and description No cover.
Authors David A. Ponce, Nora K. Foley, Michael K. O'Keeffe, Joshua M. Rosera.
New data needs 1:24,000 scale geologic mapping.
Geologic mapping and modeling needs 1:24,000 scale geologic mapping at the Mount Big Chief quadrangle.
Geophysical survey and modeling needs High resolution, Rank 1 aeromagnetic and aeroradiometric surveys.
Digital elevation data needs Lidar complete.