Investigating subglacial till dispersal using remotely piloted aircraft systems

Remotely piloted aircraft systems (RPAS) fitted with gamma-ray spectrometer and magnetometer payloads were used to detect dispersal in subglacial tills down-ice of porphyry occurrences in the Guichon Creek batholith, British Columbia, Canada. Elevation models derived from RPAS lidar and air photos were used for surficial geology mapping at 1:5000 scale (up to 0.25 m resolution). Five areas were surveyed, and results were compared to traditional equivalents (geochemistry and mineralogy samples and handheld measurements) to assess their capabilities as supplements to till sampling and surficial geology mapping. Radiogenic potassium surveys may be used to detect sediment eroded from a porphyry system; however, environmental and pedological conditions and the miniaturized RPAS system affect measurements of till. Quantifiable magnetic signals of surface sediments cannot be separated from bedrock. RPAS lidar and photogrammetry provide high-resolution digital elevation and hillshade models for mapping surficial geology and ice flow.