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National Geologic Map Database
Geologic Unit: Wisconsin
Map showing publication footprint
  • Usage in publication:
    • Wisconsin Episode
  • Modifications:
    • Principal reference
  • AAPG geologic province:
    • Illinois basin
    • Michigan basin
    • Wisconsin arch
Publication:

Hansel, A.K., and Johnson, W.H., 1996, Wedron and Mason Groups; Lithostratigraphic reclassification of deposits of the Wisconsin Episode, Lake Michigan lobe area [Illinois]: Illinois Geological Survey Bulletin, no. 104, 116 p.


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.

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