Earth & Space Science · 1980
Extraterrestrial Cause for the Cretaceous–Tertiary Extinction
Luis W. Alvarez, Walter Alvarez, Frank Asaro, Helen V. Michel
Overview
The Alvarez team proposed that a giant asteroid impact caused the mass extinction that killed the dinosaurs. Their evidence was a worldwide layer of iridium — an element rare on Earth but common in asteroids — at the geological boundary.
Established impact-driven mass extinction; later confirmed by the Chicxulub crater.
Key findings
Methods
Geochemical analysis of boundary-clay samples from multiple continents measured iridium and other trace elements by neutron activation, with quantitative modelling of the impact and its atmospheric effects.
Keywords
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