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. |