Abstract: Although the presence of radon has been reported in Yukon, the controls on radon soil gas fluxes in Yukon have not been studied. Here we report 328 radon concentration measurements collected in surficial sediment at 30 sites throughout Whitehorse during the summer of 2020 for the purpose of examining the controlling factors. The sediment types include till, glaciofluvial sand and gravel, glaciolacustrine silt, fluvial sand and gravel, and eolian sand. Average radon concentrations were compared to bedrock lithology, thickness of surficial sediment, surficial sediment type, surficial sediment grain size distribution, sorting, sediment maturity, and soil moisture to determine the first-order geological controls. Pronounced interseasonal variation was observed, but intraseasonal summer readings were relatively consistent. Positive correlation is apparent between radon concentration and grain size distribution, as well as between radon concentration and soil moisture. Negative correlation is observed between radon concentration and sediment maturity, with till and weathered bedrock displaying the highest concentrations of radon. No appreciable correlation was observed with depth to bedrock or with bedrock type. Additional data are being collected to complete the analyses in order to establish which geological and environmental factors are primary controls on radon concentration in near surface sediments.

Authors: Kishchuk, M.J., Lipovsky, P.S., Bond, J.D. and Gosse, J.C.

NTS Mapsheet(s): 105D11, 105D14

Citation: Kishchuk, M.J., Lipovsky, P.S., Bond, J.D. and Gosse, J.C., 2021. Preliminary investigation of geological controls on radon concentration in surficial sediment in Whitehorse, Yukon (NTS 105D/11, 14). In: Yukon Exploration and Geology 2020, K.E. MacFarlane (ed.), Yukon Geological Survey, p. 115–135.

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