| Basis for focus area |
Focus area represents an extension of similar magnetic anomalies associated with known IOA-IOCG deposits in the Southeast Missouri Iron Metallogenic Province (aeromagnetic anomalies > 50 nT in a 1.4 Ga granite-rhyolite terrane and a depth to crystalline basement filter of <1 km). |
| Identified resources |
None outside of Missouri where there was historical production of iron. |
| Production |
Unknown. |
| Status |
Past mining only in Missouri for Fe. |
| Estimated resources |
Unknown. |
| Geologic maps |
Horton and others (2017), scale 1: 500,000. |
| Geophysical data |
Adequate Rank 1 aeromagnetic, gravity gradiometry, and aeroradiometric data over known deposits within the St. Francois Mountains (McCafferty, 2016a,b; McCafferty and others, 2016 ; McCafferty and Johnson, 2019); inadequate data surrounding the St. Francois Mountains and through the focus area permissive for IOA/IOCG mineralization. |
| Favorable rocks and structures |
1.4 Ga felsic volcanic rocks, shallow intermediate intrusive rocks, and hypabyssal andesite-dacite intrusions. |
| Deposits |
Missouri: Pea Ridge (MRDS dep_id: 10090126; USMIN Site_ID: MO00012), Pilot Knob (MRDS dep_id: 10072191), Iron Mountain. |
| Evidence from mineral occurrences |
MRDS; USMIN. |
| Geochemical evidence |
None. |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Previous work from other sources is cited in Slack and others (2016) and references therein. |
| Cover thickness and description |
Variably covered by younger rocks. |
| Authors |
Albert H. Hofstra, Anne E. McCafferty, Warren C. Day. |
| New data needs |
Geologic mapping, high resolution geophysics. |
| Geologic mapping and modeling needs |
1:100,000 scale (estimated) map of the Precambrian surface composed of mafic to intermediate volcanic and intrusive rocks and felsic volcanic and plutonic rocks based on drill hole intercepts and geophysics. |
| Geophysical survey and modeling needs |
Aeromagnetic, gravity, magnetotelluric mapping of covered areas. Radiometric data useful for areas of exposed Precambrian rocks and mine waste piles. |
| Digital elevation data needs |
Variable lidar quality; some complete, some planned/funded, some inadequate. |
