Anatomy of a young impact crater in Central Alberta: prospects for the ‘missing’ Holocene impact record
absolute age, aerial photography, Alberta, Quaternary
Small impact events recorded on the surface of Earth are significantly underrepresented based on expected magnitude-frequency relations. We report the discovery of a 36-m-diameter late Holocene impact crater located in a forested area near the town of Whitecourt, Alberta, Canada. Although undetectable using visible imagery, the presence of the crater is revealed using a bare-Earth digital elevation model obtained through airborne light detection and ranging (LiDAR). The target material comprises deglacial Quaternary sediments, with impact ejecta burying a late Holocene soil dated to ca. 1100 14C yr B.P. Most of the 74 iron meteorites (0.1–1196 g) recovered have an angular exterior morphology. These meteorites were buried at depths <25 cm and are interpreted to result from fragmentation of the original projectile mass, either at low altitude or during the impact event. Impact of the main mass formed the simple bowl-shaped impact structure associated with an ejecta blanket and crater fill. The increasing availability of LiDAR data for many terrestrial surfaces will serve as a useful tool in the discovery of additional small impact features.
Herd, C. K., Froese, D. G., Walton, E. L., Kofman, R. S., Herd, E. K., & Duke, M. M. (2008). Anatomy of a young impact event in central Alberta, Canada; prospects for the missing Holocene impact record. Geology, 36(12), 955-958. doi:10.1130/G25236A.1
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