美国新墨西哥大学L.J. Crossey团队揭示了大峡谷的滑坡坝和古湖泊是由56年前的陨石坑撞击引发的。相关论文于2025年7月15日发表在《地质学》杂志上。

研究组假设56000年前美国亚利桑那州的陨石坑撞击引发了大峡谷的山体滑坡，从而阻塞了科罗拉多河，形成了Nankoweap古湖泊。这与冲击和地震物理兼容，可以推断出5.4级地震事件，在大峡谷减弱到3.5级的有效震级。支持这一假设的结果包括漂流木的放射性碳定年法和相关的淡水湖沉积物的发光定年法，这些沉积物保存在距离现代科罗拉多河60米以上的洞穴中。

包括斯坦顿洞穴在内的两个地点的放射性碳年龄测定表明，浮木的年龄为55.25±2.44 ka （n = 4）。与浮木相关的沉积物的发光年龄为56.00±6.39 ka （n = 2）。这6个大峡谷的日期，以及3个已公布的陨石坑撞击的年龄，在统计学上显示了难以区分的结果，支持了平均年龄为55.60±1.30 ka的一系列地质瞬时事件的假设。这项工作强调了接近技术极限的放射性碳测年的价值，多种测年方法的整合，以及与大峡谷等极端地形地区陨石撞击相关的地震和滑坡危险。

附：英文原文

Title: Grand Canyon landslide-dam and paleolake triggered by the Meteor Crater impact at 56 ka

Author: 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

Issue&Volume: 2025-07-15

Abstract: 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.

DOI: 10.1130/G53571.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G53571.1/659552/Grand-Canyon-landslide-dam-and-paleolake-triggered