title: Mass extinctions caused by large bolide impacts.
abstract: Evidence indicates that the collisions of Earth and a large piece of Solar System debris such as a meteoroid, asteroid or comet caused the great extinctions of 65 million years ago, leading to the transition from the age of the dinosaurs to the age of the mammals.
authors.affiliation: Lawrence Berkeley Laboratory, University of California, Berkeley, USA.
authors.forename: L W
authors.initials: LW
authors.lastname: Alvarez
mesh_terms: D005075:Biological Evolution; D018534:Earth, Planet; D019015:Geologic Sediments / Q000737:chemistry; D055593:Geological Phenomena; D005844:Geology; D007495:Iridium / Q000032:analysis; D019110:Meteoroids; D018543:Minor Planets; D008962:Models, Theoretical; D010163:Paleontology; D016082:Solar System
chemical_list: D007495:Iridium