The 65 Ma Chicxulub impact is known to have triggered large submarine slope
failures near the crater in the Gulf of Mexico and Caribbean. Here we show
that the impact also precipitated massive submarine failure of the contine
ntal margin around the western North Atlantic. We have identified mass-flow
deposits containing impact ejecta of Cretaceous-Paleogene boundary age in
two deep-sea cores more than 700 km from the continental margin. The mass f
lows must have originated from the continental margin because they contain
microfossils typical of shallow-water environments and sedimentary features
indicative of deposition by gravity currents. Geophysical data suggest tha
t the mass-wasting deposits may be present over the entire western North At
lantic from Puerto Rico to the Grand Banks of Canada, and that much of the
eastern margin of North America catastrophically failed during the Cretaceo
us-Paleogene impact.