Anatomy of a young impact crater in Central Alberta: prospects for the ‘missing’ Holocene impact record

Author
Herd, C. D. K.
Froese, D. F.
Walton, Erin L.
Herd, E. P. K.
Duke, J.
Faculty Advisor
Date
2008
Keywords
absolute age , aerial photography , Alberta , Quaternary
Abstract (summary)
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.
Publication Information
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
DOI
Notes
Item Type
Article
Language
English
Rights
All Rights Reserved