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The large earthquake generated by the K/T impact may have triggered underwater avalanches and tsunamis report researchers in the Aug 20 edition of the journal Geology. The researchers, led by Cathy Busby of the University of California, have been studying the remains of a massive landslide 200 metres thick, filling what was a valley, on the Baja Peninsular. Analyses of the argon produced by radioactive decay of potassium-40 contained in volcanic ashes within the landslides indicate that they formed 65.5 million years ago at the same time as the impact that caused the extinction of the dinosaurs. Busby and colleages suggest that the giant earthquake, estimated to be 13 on the Richter scale, triggered the underwater avalanches which in turn would have generated tsunamis.
The K/T impact is known to have occurred into a shallow ocean at Chicxulub in the Gulf of Mexico and would have itself generated a series of large tsunamis. Landslide deposits found along the continental slope of the Atlantic ocean may have been triggered by the tsunamis or the earthquake caused by the impact. The deposits that Busby and colleages have discovered, however, were close to the Pacific coastline and were thus probably triggered by the seismic disturbance.
More info: Geology
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