- Usage in publication:
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- Wisconsin Episode
- Modifications:
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- Principal reference
- AAPG geologic province:
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- Illinois basin
- Michigan basin
- Wisconsin arch
Summary:
Pg. 19-23. Wisconsin Episode. Generally similar in concept to Wisconsinan Age of Willman and Frye (1970, Illinois Geol. Survey Bull., no. 94). In Illinois, divided into (ascending): (1) Athens Subepisode (middle Wisconsinan) representing intervals of loess deposition (Roxana Silt) and soil formation (Farmdale Geosol); and (2) Michigan Subepisode (late Wisconsinan), representing interval of the last major glaciation (Wedron Group and part of Mason Group). Age is Pleistocene (Sangamonian to Wisconsinan Age), based on radiocarbon dating.
[Type area: Lake Michigan Lobe extending from south of Peoria, IL, to Straits of Mackinac, MI, encompassing the type sections of the constituent lithostratigraphic units.]
Source: Publication.
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 ([ ]).