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National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Horseshoe Mountain Group
  • Modifications:
    • Named
  • Dominant lithology:
    • Sandstone
    • Shale
    • Limestone
    • Dolomite
  • AAPG geologic province:
    • Denver basin
    • Piceance basin
    • South Park basin
Publication:

Gerhard, L.C., 1972, Canadian depositional environments and paleotectonics, central Colorado, IN De Voto, R.H., ed., Paleozoic stratigraphy and structural evolution of Colorado: Colorado School of Mines Quarterly, v. 67, no. 4, p. 1-36.


Summary:

Name Horseshoe Mountain Group applied to all rocks of the Sauk sequence in central CO of Late Cambrian and Early Ordovician age. In its northwest province near Glenwood Springs, Garfield Co in Piceance basin, the group is divided into the Sawatch Sandstone, Dotsero Formation (and its Glenwood Canyon and Clinetop Members) and Manitou Limestone (and its Deadhorse and Tie Gulch Members). In its southeast province--near Salida, Gunnison Co in Piceance basin, Colorado Springs, El Paso Co in Denver basin, and Fairplay, Park Co in South Park basin--the group is divided into the Sawatch Sandstone, Peerless Formation, and Manitou Limestone (and its Helena Canyon, Ptarmigan (provisional), and Fairplay (provisional) Members. The group is named for exposures on Horseshoe Mountain (the type section) near Fairplay in Park Co. Rocks of the group include conglomerate, sandstone, shale, limestone, and dolomite. Correlation chart. Thickness of group at its type section (in the southeast facies--sec. 12, T. 10 S., R. 79 W.) is 352 ft: Manitou, 167 ft; Peerless, 35 ft; and Sawatch, 150 ft. Thickness of group in northwest facies (sec. 15, T. 5 S., R. 87 W.) is 772 ft: Manitou, 156 ft; Dotsero, 96 ft; and Sawatch, 520 ft.

Source: GNU records (USGS DDS-6; Denver GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Horseshoe Mountain Group
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Piceance basin
    • South Park basin
    • Denver basin
Publication:

Gerhard, L.C., 1974, Redescription and new nomenclature of Manitou Formation, Colorado: American Association of Petroleum Geologists Bulletin, v. 58, no. 7, p. 1397-1406. [Available online, with subscription, from AAPG archives: http://www.aapg.org/datasystems or http://search.datapages.com]


Summary:

Name Fairplay Member, provisionally named as the upper member of the Manitou Limestone of Horseshoe Mountain Group in its southeastern province, replaced by name Leavick Tarn Member of Manitou Formation (rank term changed) of Horseshoe Mountain Group in its southeastern facies. This facies is present in the Salida area, Gunnison Co, Piceance basin, Colorado Springs area, El Paso Co in the Denver basin, and at Fairplay, Park Co in the South Park basin. Measured sections of Manitou.

Source: GNU records (USGS DDS-6; Denver GNULEX).


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

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