Publication Date:
2001-02-27
Description:
The Permian-Triassic boundary (PTB) event, which occurred about 251.4 million years ago, is marked by the most severe mass extinction in the geologic record. Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C60 to C200) from sediments at the PTB contain trapped helium and argon with isotope ratios similar to the planetary component of carbonaceous chondrites. These data imply that an impact event (asteroidal or cometary) accompanied the extinction, as was the case for the Cretaceous-Tertiary extinction event about 65 million years ago.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Becker, L -- Poreda, R J -- Hunt, A G -- Bunch, T E -- Rampino, M -- New York, N.Y. -- Science. 2001 Feb 23;291(5508):1530-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 USA. lbeck00@u.washington.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11222855" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Argon/analysis
;
Carbon/*analysis
;
China
;
Fossils
;
*Fullerenes
;
Geologic Sediments/*chemistry
;
Helium/analysis
;
Hungary
;
Isotopes
;
Japan
;
*Meteoroids
;
*Minor Planets
;
*Paleontology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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