GEOLOGY: A Massive Slam-Slump

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Science  15 Dec 2000:
Vol. 290, Issue 5499, pp. 2035c
DOI: 10.1126/science.290.5499.2035c

The impact of a large comet or asteroid at the end of the Cretaceous had wide-ranging effects on life and geologic processes. It generated fires and a globally distributed layer of debris, blasted material over much of the western Hemisphere, likely released seismic energy equivalent to an earthquake of magnitude 10 to 13, produced giant tsunamis in the Gulf of Mexico region, and led to a global mass extinction. Norris et al. show that the impact also resulted in widespread and massive failure and slumping along much of the eastern North American continental margin and slope. The authors identified mass flow deposits in two drill cores along the margin and correlated these layers, which occur at the Cretaceous-Tertiary boundary, with geophysical data and other studies along the continental margin from Bermuda to the Grand Banks. Collectively, these deposits may represent the largest mass-wasting deposits known on Earth. — BH

Geology 28, 1119 (2000).

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