Airborne magnetic and radiometric survey, southeastern Illinois, western Kentucky, and southern Indiana, 2019; Radiometric Data

This publication provides digital flight line data for a high-resolution magnetic and radiometric survey over an area of southeast Illinois, western Kentucky, and southern Indiana. The survey includes airborne geophysical data collected as part of the U.S. Geological Survey (USGS) Earth Mapping Resource Initiative (Earth MRI) effort (Day, 2019). Earth MRI is a cooperative effort between the USGS, the Association of American State Geologists, and other Federal, State, and private sector organizations to improve our knowledge of the geologic framework of the United States. Data for this survey were collected by EON Geosciences under contract with the USGS using a fixed wing aircraft with a magnetometer mounted in the tail stinger and a fully calibrated gamma ray spectrometer. The survey operated out of the Paducah, Kentucky airport from October of 2019 to December of 2019. The survey covers a 91-kilometer x 128-kilometer area centered on the igneous complex around Hicks Dome in Hardin County, Illinois. Data were collected along east-west flight lines spaced 200 meters apart with north-south tie lines flown every 3,000 meters. A mean terrain clearance of 116 meters was maintained except where safety dictated a higher elevation. A total of 61,974-line kilometers of data were collected. Files that are available in this publication include flight line data for the magnetic survey, flight line data for the radiometric survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. A zip file is provided that contains the contractor's deliverable products that includes Geosoft databases and grids for the magnetic and radiometric survey and the report describing the survey and data reduction.