Short Communication: Cosmogenic noble gas depletion in soils by wildfire heating

Abstract. Measurements of cosmic-ray-produced beryllium-10, neon-21, and helium-3 in quartz in a soil profile from a forested landscape in the Oregon Coast Ranges show that the cosmogenic noble gases ²¹Ne and ³He are depleted relative to ¹⁰Be in the shallow subsurface. As the noble gases are mobile in mineral grains by thermally activated diffusion and ¹⁰Be is not, this is most likely the result of surface heating by wildfires and subsequent mixing of partially degassed quartz downward into the soil. Cosmogenic noble gas depletion by wildfire heating of soils is a potential means of estimating wildfire intensity and/or frequency over pre-observational time scales.