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A Cretaceous-Tertiary mass extinction? Were most of Earth's species killed off?For the past decade, the scientific and popular press have carried frequent articles about a catastrophic mass extinction that supposedly destroyed the majority of the earth's species, including the dinosaurs, approximately 65 million years ago. Since 1980, more than 2000 papers and books have dealt with some aspect of a mass extinction at the Cretaceous-Tertiary (K/T) boundary. One authoritative estimate of the severity of the extinctions is that 60-80% of all the living species became extinct at this boundary (Raup 1988). There appears to be a general acceptance of the fact that such a great catastrophe did occur. Most of the argument among scientists now is devoted to the determination of the cause. In this article, I argue that the species changes at the K/T boundary were neither sudden nor catastrophic. They were most likely caused by a regression of sea level that led to a decrease in primary production.
Document ID
20040090106
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Briggs, J. C.
(University of South Florida St. Petersburg, FL 33701, United States)
Date Acquired
August 21, 2013
Publication Date
October 1, 1991
Publication Information
Publication: Bioscience
Volume: 41
Issue: 9
ISSN: 0006-3568
Subject Category
Geosciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
Non-NASA Center
NASA Discipline Number 52-40
NASA Program Exobiology

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