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Map showing publication footprint
  • Usage in publication:
    • Grand Detour formation
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Dolomite
    • Limestone
  • AAPG geologic province:
    • Wisconsin arch
Publication:

Templeton, J.S., and Willman, H.B., 1952, Guidebook for the 16th annual field conference, central northern Illinois: Tri-State Annual Field Conference Guidebook, October 11-12, 1952, no. 16, 47 p., Also issued as Illinois State Geol. Survey Gdbk., 2nd ser., 1952. http://archive.org/details/guidebookforsixt02tris


Summary:

Pg. 6, fig. 3. Grand Detour formation of Platteville group. Consists of dolomite or limestone, alternately pure and argillaceous, partly cherty, thin- to thick-bedded. Thickness about 500 feet. Subdivided into seven members (ascending): Dement, Walgreen, Stillman, Clement, Hely, Victory, and Forreston (all new). Underlies Nachusa formation (new); overlies Mifflin formation. Age is Middle Ordovician.
[Notable exposures in Dixon-Oregon area, northern IL.]

Source: US geologic names lexicon (USGS Bull. 1200, p. 1563).


Map showing publication footprint
  • Usage in publication:
    • Grand Detour Formation
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Wisconsin arch
Publication:

Willman, H.B., and Kolata, D.R., 1978, The Platteville and Galena Groups in northern Illinois: Illinois Geological Survey Circular, no. 502, __ p.


Summary:

Pg. 30. Grand Detour Formation. Revised in Illinois to include Cowen Member at base, below Stillman Member. Overlies Mifflin Formation. Age is Middle Ordovician. [See entry under Cowen.]

Source: Inferred from US geologic names lexicon (USGS Bull. 1564, p. 41).


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 ( ).

Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).

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