Aeromagnetic data

aeromagnetic map of Stearns County
This image, derived from airborne magnetometer data, reflects the variable magnetic character of the Precambrian bedrock units in Stearns County. Flight lines were spaced 400-500 meters apart and averaged 150 meters above the ground. Maps such as this are an essential tool for geologists, especially in Minnesota where much of the bedrock is covered by thick Quaternary glacial deposits. The accompanying Precambrian bedrock map of Stearns County shows a geologic interpretation of the magnetic data. The contacts, diabase dikes, and faults from that map are shown on the map above.
* Minnesota geology