Helicopter-borne magnetic and radiometric gaophysical survey in Kviteseid area, Telemark, Norway

Abstract

In cooperation with the geologist for Buskerud, Telemark and Vestfold, the NGU conducted an airborne geophysical survey in Kviteseid area in May 2012. This report describes and documents the acquisition, processing and visualization of recorded datasets. The geophysical survey results reported herein are 3514 line km. The optically pumped cesium magnetometer and 1024 channels RSX-5 spectrometer was used for data acquisition. The survey was flown with 100 m line spacing, line direction of 130 deg - 210 deg and average speed of 98 km\/h. A smaller area was also flown in 100 m line spacing 50 m away from larger flight lines so that smaller area could be covered with 50 m line spacing. The average terrain clearance of the helicopter was 65 m. Collected data were processed in NGU using Geosoft Oasis Montaj software. Raw total magnetic field data were corrected for diurnal variation and also for International Geomagnetic Reference Field (IGRF). Finally, some along-line noises were removed using standard micro-leveling algorithm. Radiometric data were processed using standard procedures recommended by International Atomic Energy Association (IAEA). Final processed data were gridded with the cell size of 25 m and 12 m for 100 m and 50 m line spacing, respectively. They are presented as shaded relief maps at the scale of 1:20 000 and 1:10 000, respectively