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National Geologic Map Database

Geologic Unit: Keweenawan

Usage:

Keweenawan Supergroup (MI*,WI*,MN*)


Subunits:

Bergland Group (MI*,WI*), Bessemer Quartzite (MI*,WI*), Jacobsville Sandstone (MI*), Oronto Group (MI*,MN*,WI*), Powder Mill Group (MI*,WI*), Bayfield Group (WI*), Chengwatana Volcanic Group (WI*,MN*), Beaver Bay Complex (MN), Duluth Complex (MN*), Fond Du Lac Formation (MN*), Hinckley Sandstone (MN*), Hovland Diabase Complex (MN), North Shore Volcanic Group (MN*), Puckwunge Formation (MN), Reservation River Diabase Complex (MN), Solor Church Formation (MN).


Geologic age:

Precambrian*
Proterozoic, Middle*
Proterozoic, Late(?)*


Type section, locality, area and/or origin of name:

Exposures on Keweenaw Peninsula, northern MI (Brooks, 1876).


AAPG geologic province:

Lake Superior region*
Wisconsin arch*
Sioux uplift*


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

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).