The lower peninsula contains the Michigan Basin, an area of sedimentary rocks covered by glacial deposits. The upper peninsula is more mineralogically diverse with large deposits of native copper (the Keweenaw peninsula) in Keweenaw, Houghton and Ontonagon counties. Precambrian iron formation was mined in the Gogebic, Marquette and Menominee iron ranges in Gogebic, Iron, Dickinson and Marquette counties. There are also kimberlites and gold deposits in this part of the state.
This general locality has been created so people who have copper, silver and other specimens from the Keweenaw peninsula but with no specific known locality can associate images with this locality and not have to take a guess and hope that they come from say Keweenaw County. The specimens have a much better chance of having been found in Keweenaw, Houghton and Ontonagon counties than just taking a guess at one of the more specific localities.
[Rock Currier 2009]
References:
- E. W. Heinrich and G. W. Robinson (2004): Mineralogy of Michigan, xx pp.
Mineral List:14 entries listed. 11 valid minerals.
The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database!