Eagle Basin

Region West, Rocky Mountains
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Sub-basins of the Eagle basin underlain by salt that may be potash-bearing as outlined by Orris and others (2014). Updated with the 1:500,0000 scale Tweto (1979) geologic map polygons of the evaporite facies.
Identified resources Historical production of gypsum.
Production Unknown.
Status Past mining of gypsum in one area.
Estimated resources Unknown.
Geologic maps Many Colorado Geological Survey 1:24,000 scale maps exist in area-too many to list here. Ellis and Freeman (1984), scale 1:100,000; Kellogg and others (2011), scale 1:100,000; Madole (1989), scale 1:100,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Eagle Valley evaporite.
Deposits Avon (MRDS dep_id: 10288155), Blowout Hill (gypsum past producers).
Evidence from mineral occurrences MRDS.
Geochemical evidence Mineralogy: sylvite, carnallite, langbeinite.
Geophysical evidence No data.
Evidence from other sources No data.
Comments From Mallory (1971): "The presence of halite in the basin has been known since 1949 when the Champlin Refining Co. drilled their Black 1 well near the town of Eagle. The presence of potash and other salts of commercial value was suspected for several years and has been confirmed by recent drilling." From Max A. Krey (written comm., 1967): "In 1966, the Pittsburg and Midway Coal Mining Co. drilled two holes north of the town of Gypsum (sections 23 and 29, T. 4 S., R. 85 W.) (pi. 3B) for the Gulf Oil Corp. to test for presence of salts of potassium. In both holes halite is present at a depth of about 1,400 feet, and two beds containing potash, 6 and 7 feet thick, were reported at depths of between 3,600 and 4,000 feet." No commercial development by the companies concerned is contemplated.
Cover thickness and description 3,600 to 4,000 feet of Paleozoic, Mesozoic, Cenozoic cover.
Authors Jane M. Hammarstrom, Michael K. O'Keeffe.
New data needs 1:24,000 scale geologic mapping would need to be conducted in many quadrangles (too many to list here). There is a potential that a generalized compilation map of some of the areas could be completed. Some quadrangles may be more important than others.
Geologic mapping and modeling needs Compilation map, additional geologic mapping at 1:24,000 scale (too many quadrangles to list here).
Geophysical survey and modeling needs High resolution Rank 1 aeromagnetic and aeroradiometric survey, although may not be a good geophysical target.
Digital elevation data needs Lidar is adequate.