| Basis for focus area |
Archean and younger granites suspected to have significant potential for LCT pegmatites, based on their setting (see Selway and others, 2005). |
| Identified resources |
None known. |
| Production |
No known production. |
| Status |
Unknown. |
| Estimated resources |
No data. |
| Geologic maps |
Sims and others (1991), scale 1:1,000,000. |
| Geophysical data |
Inadequate Rank 5 aeromagnetic data with poor ground gravity coverage in central and western North and South Dakota. Inadequate Rank 3 aeromagnetic data in coverage areas of northern and southern MN. Inadequate aeroradiometric coverage. |
| Favorable rocks and structures |
Archean and Paleoproterozoic granites, some with known pegmatites. |
| Deposits |
No data. |
| Evidence from mineral occurrences |
No data. |
| Geochemical evidence |
No data. |
| Geophysical evidence |
Weakly magnetized granites. |
| Evidence from other sources |
Favorable comparisons to areas with known potential (see Selway and others, 2005). |
| Cover thickness and description |
Total cover is variable from 0-1000 feet; The most common overburden is Quaternary glacial sediment (till) which can range from 0-over 500 feet thick. Patchy Mesozoic (Cretaceous) and Paleozoic strata up to ~300 feet thick are locally present beneath glacial sediments. Locally saprolite of several tens of feet covers solid Precambrian bedrock. |
| Authors |
Benjamin J. Drenth, Amy Block. |
| New data needs |
New mapping; high resolution geophysics. |
| Geologic mapping and modeling needs |
More detailed mapping, to the extent allowed by glacial cover. |
| Geophysical survey and modeling needs |
Rank 1 aeromagnetic data, also radiometric data. |
| Digital elevation data needs |
Lidar adequate over part of focus area, inadequate over others. |
