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Mass extinction caused by large bolide impactsA history and development status assessment is presented for the hypothesis that the great extinction of living species 65 million years ago, at the boundary between the Tertiary and Cretaceous geological ages, was due to the collision of a meteoroid, asteroid, or comet with the earth. The initial, deeply suggestive indication of the extraterrestial origin of the extinction-initiating mechanism was the detection of an exceptionally high concentration of iridium at the stratigraphic position of the extinction. Detailed computer modeling of the atmospheric effect of such a bolide impact has shown that the earth would have first grown intensely cold during a period of darkness due to particulate debris clouds in the upper atmosphere, followed by an enormous increase in global temperatures as the debris cleared, created by the persistence of greenhouse-effect gases; this heating would have been especially lethal to numerous forms of life.
Document ID
19870061224
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Alvarez, Luis W.
(California, University Berkeley, United States)
Date Acquired
August 13, 2013
Publication Date
July 1, 1987
Publication Information
Publication: Physics Today
Volume: 40
ISSN: 0031-9228
Subject Category
Geosciences (General)
Accession Number
87A48498
Distribution Limits
Public
Copyright
Other

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