Usage:
Ironwood Iron-Formation of Menominee Group of Marquette Range Supergroup (recognized locally in MI*,WI*)
Notable exposures in Gogebic iron range, Northern Peninsula.
Subunits:
(alphabetical) --all in MI*,WI*: Anvil Member, Norrie Member, Pence Member, Plymouth Member, Yale Member.
Geologic age:
Paleoproterozoic*
Type section, locality, area and/or origin of name:
Ironwood, Gogebic Co., Northern Peninsula, northwestern MI (Van Hise, 1901).
AAPG geologic province:
Lake Superior region*
Wisconsin arch*
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 ([ ]).