Publication Date:
1998-10-30
Description:
High-precision mass spectrometric analysis of chromium in sediment samples from the Cretaceous-Tertiary (K-T) boundary coincident with the extinction of numerous organisms on Earth confirms the cosmic origin of the K-T phenomenon. The isotopic composition of chromium in K-T boundary samples from Stevns Klint, Denmark, and Caravaca, Spain, is different from that of Earth and indicates its extraterrestrial source. The chromium isotopic signature is consistent with a carbonaceous chondrite-type impactor. The observed differences in the chromium isotopic composition among various meteorite classes can serve as a diagnostic tool for deciphering the nature of impactors that have collided with Earth during its history.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shukolyukov, A -- Lugmair, G W -- New York, N.Y. -- Science. 1998 Oct 30;282(5390):927-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0212, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9794759" target="_blank"〉PubMed〈/a〉
Keywords:
Chromium/analysis
;
Chromium Isotopes/*analysis
;
Denmark
;
*Earth (Planet)
;
Geologic Sediments/*chemistry
;
Mass Spectrometry
;
*Meteoroids
;
Spain
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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