Hermosa Group

Usage of Geologic Unit Name: Hermosa Formation (AZ*,CO*,NM*,UT*) Hermosa Group (AZ*,CO*,NM*,UT*)
Age: Pennsylvanian, Middle* Atokan* Desmoinesian* Pennsylvanian, Late* Missourian* Virgilian*
Geologic Province: Black Mesa basin* Paradox basin* San Juan Mountains province* San Juan basin* Plateau sedimentary province*
Areal Extent: AZ(ne)* CO(sw)* NM(nw)* UT(se)*

Type Locality: Not designated. Named for Hermosa Creek, Durango quad, La Plata Co., CO (Spencer, 1900). Composite Type section designated in secs. 26 and 35, T. 37 N., R. 9 W., La Plata Co., CO (Roth, 1934)

Subunits: Group rank (alphabetical): Honaker Trail Formation (AZ*,CO*,NM*,UT*), Lime Ridge Formation (CO,UT), Paradox Formation (CO*,NM,UT), Pinkerton Trail Formation (AZ*,CO*,NM*,UT*) or Pinkerton Trail Limestone (CO,UT). Formation rank: Paradox Member (AZ,CO,UT).
Unit Name History: Named Hermosa Formation (Spencer, 1900). Lower contact revised (Cross and Howe, 1905). Overview (Burbank, 1930). Lower contact revised (Baker and others, 1933). Overview; Composite type section designated (Roth, 1934). Revised, restricted to carbonate-clastic facies above the Paradox Formation (rank raised) and below the Rico facies of Cutler Formation (Wengerd and Strickland, 1954). Overview (Herman and Barkell, 1957). Revised, divided into Lime Ridge, Pinkerton Trail, Paradox, and Honaker Trail formations; Overview (Clair, 1958). Revised, raised to group rank and divided into Pinkerton Trail, Paradox and Honaker Trail Formations (Wengerd and Matheny, 1958). Areal limits (Peterson and Barnum, 1973). Overview (Hite and others, 1984). Upper contact revised (Loope and others, 1990). Overview (Condon, 1992).


Spencer, A.C., 1900, The sedimentary formations, Chapter 2, IN Cross, C.W., and Spencer, A.C., Geology of the Rico Mountains, Colorado: U.S. Geological Survey Annual Report, 21, pt. 2, p. 37-88.

Cross, C.W. and Howe, Ernest, 1905, Geography and general geology of the quadrangle, IN Description of the Silverton quadrangle [Colorado]: U.S. Geological Survey Geologic Atlas of the United States, Silverton folio, no. 120, 34 p.

Burbank, W.S., 1930, Revision of geologic structure and stratigraphy in the Ouray district of Colorado, and its bearing on ore deposition: Colorado Scientific Society Proceedings, v. 12, no. 6, p. 151-232.

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.

Roth, R.I., 1934, Type section of the Hermosa formation, Colorado: American Association of Petroleum Geologists Bulletin, v. 18, no. 7, p. 944-947.

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.

Clair, J.R., 1958, Subsurface stratigraphy of the Pennsylvanian of the Paradox basin [Colorado Plateau], IN Symposium on Pennsylvanian rocks of Colorado and adjacent areas: Rocky Mountain Association of Geologists Field Conference Guidebook, no. 10, p. 31-46.

Peterson, Fred and Barnum, B.E., 1973, Geologic map and coal resources of the northeast quarter of the Cummings Mesa quadrangle, Kane County, Utah: U.S. Geological Survey Coal Investigations Map, C-63, 2 sheets, scale 1:24,000.

Hite, R.J., Anders, D.E. and Ging, T.G., 1984, Organic-rich source rocks of Pennsylvanian age in the Paradox basin of Utah and Colorado, IN Woodward, Jane, Meissner, F.F., and Clayton, J.L., editors, Hydrocarbon source rocks of the greater Rocky Mountain region: Rocky Mountain Association of Geologists Field Conference Guidebook, p. 255-274.

Loope, D.B., Sanderson, G.A. and Verville, G.J., 1990, Abandonment of the name "Elephant Canyon Formation" in southeastern Utah; physical and temporal implications: The Mountain Geologist, v. 27, no. 4, p. 119-130.

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.

Ritter, Scott M., Barrick, James E., and Skinner, M. Randall, 2002, Conodont sequence biostratigraphy of the Hermosa Group (Pennsylvanian) at Honaker Trail, Paradox Basin, Utah: Journal of Paleontology, v. 76, no. 3, p. 495-517.

Gianniny, Gary L., 2000, Possible tectonic origin of basement derived siliciclastics, earliest Desmoinesian Hermosa Group, SW Paradox Basin, Utah: Geological Society of America, Abstracts with Programs, v. 32, no. 7, p. 466.

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., 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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Note that data on this page contains information that has been partly revised from bibliographic resources available via the National Geologic Map Database GEOLEX:
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Last modified: 1/7/2011