variants: or Alvarez hypothesis
Definition of Alvarez theory
: a theory in paleontology: the majority of dinosaurs were rendered extinct at the end of the Cretaceous period by the effects (such as volcanic activity, fires, intensely acidic rain, and the blocking of sunlight) of a giant asteroid impacting the earth Then geologists traced the ghostly outlines of the buried Chicxulub crater, and the Alvarez theory became so widely accepted that the menace of death from above is now part of popular lore.— Timothy Ferris, New York Times, 25 May 1997 The Alvarez theory is based on the fact that there is a worldwide geologic layer of iridium deposited at about the same time that fossil records show extinction of the dinosaurs and many other animal species. — Toronto Star, 14 June 1991 Many other scientists—especially traditional geologists and paleontologists—greeted the Alvarez hypothesis with great skepticism, sometimes with open derision.— Robert C. Cowen, Christian Science Monitor, 20 June 1989
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