2025-07-15 アリゾナ大学
Schematic illustration outlining the locations of the dam and the ancient lake caused by blocking of the Colorado River.
Courtesy of Chris Baisan
＜関連情報＞
- https://news.arizona.edu/news/did-meteor-impact-trigger-landslide-grand-canyon
- https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G53571.1/659552/Grand-Canyon-landslide-dam-and-paleolake-triggered
グランドキャニオンの地すべりダムと古生物：56 kaのメテオクレーター衝突が引き金となった
Grand Canyon landslide-dam and paleolake triggered by the Meteor Crater impact at 56 ka
K.E. Karlstrom;C.H. Baisan;D.A. Kring;R. Hereford;C. Turney;A. Hogg;L.M. Norman;P. O’Brien;J.G. Palmer;T.M. Rittenour;J. Ballensky;L.J. Crossey
Geology Published:July 15, 2025
DOI:https://doi.org/10.1130/G53571.1
This paper hypothesizes that the Meteor Crater impact in Arizona, USA, 56,000 years ago triggered landslides in Grand Canyon that dammed the Colorado River and formed Nankoweap paleolake. This is compatible with shock and earthquake physics for the impact that infer a M5.4 seismic event, attenuated to an effective magnitude of M3.5 at Grand Canyon. Results that support the hypothesis include radiocarbon dating of driftwood and luminescence dating of associated slack-water lake sediments that are preserved in caves up to 60 m above the modern Colorado River. Radiocarbon ages from two locations, including Stanton’s Cave, date the driftwood as 55.25 ± 2.44 ka (n = 4). Sediments associated with the driftwood gave a luminescence age of 56.00 ± 6.39 ka (n = 2). These six Grand Canyon dates, and three published ages for the Meteor Crater impact, show statistically indistinguishable results that support the hypothesis for a geologically instantaneous series of events with a mean age of 55.60 ± 1.30 ka. This work highlights the value of radiocarbon dating near the limits of the technique, integration of multiple dating methods, and seismic and landslide hazards associated with meteorite impacts in regions of extreme topography like Grand Canyon.
