Toward a theory of impact crises



In a certain sense, the impact explanation for the mass extinction at the end of the Cretaceous had its origin in Lamont Hall. A couple of years after I came to Lamont in 1971, I started working with another new Lamonter, Bill Lowrie, now at Eidgenössiche Technische Hochschule (ETH), Zürich, on the paleomagnetism of pelagic limestones in Italy. We went to the little medieval city of Gubbio because of the very complete section of Upper Cretaceous and Lower Tertiary limestones that is exposed in the Bottaccione Gorge, which cuts through the mountains behind the town.