Use of Airborne Gamma Radiometrics to Infer Soil Properties for a Forested Area in British Columbia, Canada

Abstract

We obtained radiometric data from a public-domain archive maintained by Natural Resources Canada and processed them to produce a ternary image for a portion of the Cariboo region. A field program was used to evaluate what information could be reliably inferred from the available data. This initial investigation confirmed that the radiometrics for this area exhibited consistent and useful patterns to interpret the lithology, mineralogy, depth, and moisture status of the surficial materials. Different colour patterns in the ternary image correlated well with different compositions of the various tills. We noted a clear association between higher values of radioactive emission and more recently deposited aeolian, alluvial, and glaciofluvial sediments that contained higher concentrations of relatively unweathered minerals. We observed a clear pattern of lower emission from wetlands and areas of wet soil. Airborne radiometrics, even at 500-m line spacing, provided invaluable and precise information—not otherwise obtainable—for mapping or modelling spatial variation in properties of the surficial material within the forested study area in British Columbia. We recommend further investigations to develop operational procedures for the use of such data in mapping surficial materials.