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Busby, C.J., G. Yip, et al. 2002. Coastal landsliding and catastrophic sedimentation triggered by Cretaceous-Tertiary bolide impact: A Pacific margin example? Geology 30(Aug.):687-690.

Evidence for a catastrophic underwater landsliding attributed to bolide impact-related seismic shocking at the K/Pg boundary is found whitin coastal paleovalley in Baja California, Mexico (near El Rosario) at depths of about 4,000 meters.

This 5-km-wide, 15-km-long, and 200-m-deep coastal paleovalley formed by massive gravitational collapses and rapidly filled with coastal (shallow marine and lesser fluvial) gravels and sands, as well as slide sheets of marine mudstone that range from meters to kilometers in length. Laser-heating 40Ar/39Ar data for biotite, hornblende, and plagioclase (single crystal and bulk step heating) on a 20-m-thick pumice lapilli tuff in the middle of the valley fill give an age of 65.5 ± 0.6 Ma.

This research provides evidence of giant landslides and catastrophic sedimentation 1800 km from the bolide impact site. The Yucatan impact was setting off earthquakes with magnitudes estimated at 10 to 13. The seismic shock waves generated meter-high vibrations in Earth\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s crust all along the east coast of North America. Sediment from shallow waters where sliding off the continental shelf. Once the ooze settled, it may have blanketed a region as large as 3.9 million square kilometers on the deep ocean floor.

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