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Title: What caused the mass extinction An extraterrestrial impact

The authors and other investigators discovered iridium in the clays that mark the sudden disappearance of dinosaurs from the fossil record. Because iridium is rare in the earth's crust but abundant in some meteorites, they concluded that a giant meteorite collided with the earth, hurling megatons of debris into the atmosphere. This paper describes and discusses the accumulating evidence that suggests an asteroid or comet caused the Cretaceous extinction.
Authors:
 [1] ;  [2]
  1. (Univ. of California, Berkeley (USA))
  2. (Lawrence Berkeley Laboratory, CA (USA))
Publication Date:
OSTI Identifier:
5316291
Resource Type:
Journal Article
Resource Relation:
Journal Name: Scientific American; (United States); Journal Volume: 263:4
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; CRETACEOUS PERIOD; BOUNDARY CONDITIONS; IRIDIUM; ECOLOGICAL CONCENTRATION; TERTIARY PERIOD; ANIMALS; BIOLOGICAL EXTINCTION; CONTINENTAL CRUST; CRYSTAL STRUCTURE; FOSSILS; GEOLOGIC HISTORY; GEOLOGIC SURVEYS; IMPACT SHOCK; LAYERS; METEORITES; QUARTZ; CENOZOIC ERA; CHALCOGENIDES; EARTH CRUST; ELEMENTS; GEOLOGIC AGES; MESOZOIC ERA; METALS; MINERALS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; PLATINUM METALS; SILICON COMPOUNDS; SILICON OXIDES; SURVEYS; TRANSITION ELEMENTS 580000* -- Geosciences