Reprocessing and compilation of radiometrics data from Finnmark and northern Troms
As part of the MINN program (Mineral resources in North Norway), NGU needed a reprocessing of all radiometric data available from the Finnmark and northern Troms counties. It was also of interest to merge and compile these data with the recent radiometric data acquisition from MINN airborne surveys. Each survey area was reprocessed separately using manual and automated procedures. Coarse manual adjustments were often needed to avoid creating artifacts from the various filters applied. Micro-leveling technique was preferred to reduce the linear trends caused along the flown lines. Each radio-element (potassum, thorium and uranium) count grid required different adjustments and filering parameters. Data (in counts per second) were gridded and the coefficients required for the concentration conversion were calculated from a statistical analysis using pre-existing known concentration from the Finnmark area. Concentration grids were calculated and merged to the grids obtained in the recent MINN surveys. Geosoft Oasis Montaj software was used to perform all the processing steps. Maps of each radio-element are presented at a scale of 1:500,000 in UTM 34N projection and WGS-84 datum.