Paradox Formation

Usage of Geologic Unit Name:
Paradox Member of Hermosa Formation (CO,UT)
Paradox Formation of Hermosa Group (AZ*,CO*,NM*,UT*)
Pennsylvanian, Middle*
Desmoinesian, early
Geologic Province:
Black Mesa basin
San Juan basin
Paradox basin*
Areal Extent:
Type Locality:
Not designated. Named for exposures in Paradox Valley, Montrose Co., CO. Described from J.H. Shafer well no. 1 in sec. 16, T. 27 S., R. 20 E., San Juan Co., UT (Baker and others, 1933).
Subsurface reference section: between depths of 5420-9600 ft in Reynolds Mining Co., No. 1 Egnar well in sec. 14, T. 43 N., R. 19 W., San Miguel Co., CO (Baars and others, 1967).

Formation rank: Desert Creek zone.

The name "Caprock Member" was used in to designate upper part of Paradox Formation above salts.

Unit Name History:
Named (Baker and others, 1933). Revised, reduced rank to member of Hermosa formation (N.W. Bass, 1944, USGS Oil and Gass Inv. Prelim. Chart 7) [Geologic names lexicon, USGS Bull. 1200]. Revised, raised to formation rank (Wengerd and Strickland, 1954). Desert Creek zone (oil producing zone) named and assigned to upper part of Paradox Member of Hermosa Formation (Herman and Barkell, 1957). Used as middle formation of Hermosa Group (Wengerd and Matheny, 1958). Lower boundary revised; Subsurface reference section designated; Areal limits (Baars and others, 1967). Not used in Eagle basin (Bartleson and others, 1968). Overview (Condon, 1992). Areal limits (Huffman and Condon, 1993).


Baker, A.A., Dane, C.H. and Reeside, J.B., Jr., 1933, Paradox Formation of eastern Utah and western Colorado: American Association of Petroleum Geologists Bulletin, v. 17, no. 8, p. 963-980.

Wengerd, S.A. and Strickland, J.W., 1954, Pennsylvanian stratigraphy of Paradox salt basin, Four Corners region, Colorado and Utah: American Association of Petroleum Geologists Bulletin, v. 38, no. 10, p. 2157-2199.

Herman, G. and Barkell, C.A., 1957, Pennsylvanian stratigraphy and productive zones, Paradox salt basin: American Association of Petroleum Geologists Bulletin, v. 41, no. 5, p. 861-881.

Wengerd, S.A. and Matheny, M.L., 1958, Pennsylvanian system of the Four Corners region: American Association of Petroleum Geologists Bulletin, v. 42, no. 9, p. 2048-2106.

Baars, D.L., Parker, J.W. and Chronic, J., 1967, Revised stratigraphic nomenclature of Pennsylvanian System, Paradox basin: American Association of Petroleum Geologists Bulletin, v. 51, no. 3, p. 393-403.

Bartleson, B.L., Bryant, Bruce and Mutschler, F.E., 1968, Permian and Pennsylvanian stratigraphy and nomenclature, Elk Mountains, Colorado, IN Geological Survey research 1968: U.S. Geological Survey Professional Paper, 600-C, p. C53-C60.

Condon, S.M., 1992, Geologic framework of pre-Cretaceous rocks in the Southern Ute Indian Reservation and adjacent areas, southwestern Colorado and northwestern New Mexico, IN Geology and mineral resources of the Southern Ute Indian Reservation: U.S. Geological Survey Professional Paper, 1505-A, p. A1-A56.

Huffman, A.C., Jr. and Condon, S.M., 1993, Stratigraphy, structure, and paleogeography of Pennsylvanian and Permian rocks, San Juan basin and adjacent areas, Utah, Colorado, Arizona, and New Mexico, IN Evolution of sedimentary basins, San Juan basin: U.S. Geological Survey Bulletin, 1808-O, p. O1-O44

Chidsey, Thomas C., Jr., Morgan, Craig D., Eby, David E., Brinton, Lise., and Hartman, Kris, 1996, Carbonate mound reservoirs in the Paradox Formation., an outcrop analogue along the San Juan River, southeastern Utah: AAPG Bulletin, v. 80, no. 6, p. 968.

Rueger, Bruce F., 1996, Palynology and its relationship to climatically induced depositional cycles in the Middle Pennsylvanian (Desmoinesian) Paradox Formation of southeastern Utah: U. S. Geological Survey Bulletin B 2000-K, p. Kl-K22.

Raup, Omer B., and Hite, Robert J., 1996, Bromine geochemistry of chloride rocks of the Middle Pennsylvanian Paradox Formation of the Hermosa Group, Paradox Basin, Utah and Colorado: U.S. Geological Survey Bulletin B 2000-M, p. M1-M116.

Tuttle, Michele L., Klett, Timothy R., Richardson, Mark., and Breit, George N., 1996, Geochemistry of two interbeds in the Pennsylvanian Paradox Formation, Utah and Colorado; a record of deposition and diagenesis of repetitive cycles in a marine basin: U.S. Geological Survey Bulletin B 2000-N, p. N1-N86.

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Last modified: 1/7/2011