| Basis for focus area |
Archean gneiss terrane of the Southern Complex (Wisconsin/Michigan) and the Minnesota River Valley terrane (Minnesota). Minnesota: bedrock constrained by the Great Lakes Tectonic Zone north) and the Spirit Lake discontinuity (south), and the Midcontinent Rift System (east); Michigan/Wisconsin: bedrock bounded by the Great Lakes Tectonic Zone (north) and Niagara fault zone (south), and the Midcontinent Rift System (east and west). |
| Identified resources |
Unknown. |
| Production |
Unknown. |
| Status |
Unknown. |
| Estimated resources |
Unknown. |
| Geologic maps |
Jirsa and others (2012), scale 1: 500,000; Cannon and Ottke (1999), compilation scale 1:100,000. |
| Geophysical data |
Mostly (>50%) inadequate aeromagnetic coverage; inadequate aeroradiometric coverage. |
| Favorable rocks and structures |
Archean granites with some known pegmatites, also some Paleoproterozoic granites. |
| Deposits |
No data. |
| Evidence from mineral occurrences |
Reported occurrences of enrichment in LREE and HREE, as well as Ta and F in pegmatites. |
| Geochemical evidence |
No data. |
| Geophysical evidence |
No data. |
| Evidence from other sources |
No data. |
| Comments |
No reported mineralization, but rock type is permissive for possible critical mineral deposits. |
| Cover thickness and description |
Some surface exposures; glacial cover (<50 m). |
| Authors |
Benjamin J. Drenth, Klaus Schulz. |
| New data needs |
New mapping, high resolution geophysics. |
| Geologic mapping and modeling needs |
Need new geologic mapping. |
| Geophysical survey and modeling needs |
Need aeromagnetic, radiometric, and gravity data collection. |
| Digital elevation data needs |
Lidar adequate. |
