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The case for extraterrestrial causes of extinctionThe dramatic increase in our knowledge of large-body impacts that have occurred in Earth's history has led to strong arguments for the plausibility of meteorite impact as a cause of extinction. Proof of causation is often hampered, however, by our inability to demonstrate the synchronism of specific impacts and extinctions. A central problem is range truncation: the last reported occurrences of fossil taxa generally underestimate the true times of extinction. Range truncation, because of gaps in sedimentation, lack of preservation, or lack of discovery, can make sudden extinctions appear gradual and gradual extinctions appear sudden. Also, stepwise extinction may appear as an artefact of range truncation. These effects are demonstrated by experiments performed on data from field collections of Cretaceous ammonities from Zumaya (Spain). The challenge for future research is to develop a new calculus for treating biostratigraphic data so that fossils can provide more accurate assessments of the timing of extinctions.
Document ID
20040089984
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Raup, D. M.
(University of Chicago Illinois 60637, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Philosophical transactions of the Royal Society of London. Series B, Biological sciences
Volume: 325
ISSN: 0962-8436
Subject Category
Geosciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG2-237
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Exobiology

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