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Basaltic explosive volcanism, but no comet impact, at the Paleocene-Eocene boundary: high-resolution chemical and isotopic records from Egypt, Spain and Denmark

Schmitz, Birger LU ; Peucker-Ehrenbrink, B; Heilmann-Clausen, C; Aberg, G; Asaro, F and Lee, CTA (2004) In Earth and Planetary Science Letters 225(1-2). p.1-17
Abstract
In the search for a triggering mechanism for the Paleocene-Eocene (P-E) boundary event, 55 Ma, centimeter-resolution chemical (e.g., Ir, Os, Pt) and isotope (e.g., (OS)-O-187/Os-188, He-3/He-4, Sr-87/Sr-86) records across this boundary have been established for six uplifted marine sections in Egypt, Spain and Denmark. The sections studied represent some of the stratigraphically most complete records across the onset of the carbon isotopic excursion (CIE) and associated benthic foraminifera extinctions that mark the Paleocene-Eocene boundary. High-sensitivity analyses failed to uncover evidence of extraterrestrial element or isotope enrichments in the six sections, refuting the hypothesis of a major comet impact at the boundary. Preliminary... (More)
In the search for a triggering mechanism for the Paleocene-Eocene (P-E) boundary event, 55 Ma, centimeter-resolution chemical (e.g., Ir, Os, Pt) and isotope (e.g., (OS)-O-187/Os-188, He-3/He-4, Sr-87/Sr-86) records across this boundary have been established for six uplifted marine sections in Egypt, Spain and Denmark. The sections studied represent some of the stratigraphically most complete records across the onset of the carbon isotopic excursion (CIE) and associated benthic foraminifera extinctions that mark the Paleocene-Eocene boundary. High-sensitivity analyses failed to uncover evidence of extraterrestrial element or isotope enrichments in the six sections, refuting the hypothesis of a major comet impact at the boundary. Preliminary searches for other impact-indicative features, such as spherules or shocked quartz, also gave negative results. In the Danish section studied, three basaltic Ir-rich ash layers occur at the Paleocene-Eocene boundary, but no similar ashes were found in Egypt or Spain. The three ashes represent the earliest known manifestation of an unusual I to 2 million year long phase of explosive basaltic volcanism in the Faero-Greenland region. This volcanism is synchronous with major flood basalt effusions in East Greenland and is associated with prominent paleogeographic changes in the high-latitude North Atlantic region. Discharge of mantle-derived Os to seawater during this volcanism may explain a small decrease in (OS)-O-187/(OS)-O-188 ratio at the Paleocene-Eocene boundary in the Zumaya section in Spain. The environmental perturbations at the Paleocene-Eocene boundary appear to have been triggered by basaltic volcanism, but any model for the detailed causal relation remains speculative. (C) 2004 Elsevier B.V. All rights reserved. (Less)
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author
organization
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Contribution to journal
publication status
published
subject
keywords
osmium isotopes, iridium, flood basalt volcanism, comet impact, Paleocene-Eocene boundary, IETM, carbonisotopic excursion
in
Earth and Planetary Science Letters
volume
225
issue
1-2
pages
1 - 17
publisher
Elsevier
external identifiers
  • wos:000223824100001
  • scopus:4344573187
ISSN
1385-013X
DOI
10.1016/j.epsl.2004.06.017
language
English
LU publication?
yes
id
2ead9605-a218-4e18-868f-7655ca17cc2e (old id 267526)
date added to LUP
2007-10-31 13:13:44
date last changed
2017-07-23 03:57:40
@article{2ead9605-a218-4e18-868f-7655ca17cc2e,
  abstract     = {In the search for a triggering mechanism for the Paleocene-Eocene (P-E) boundary event, 55 Ma, centimeter-resolution chemical (e.g., Ir, Os, Pt) and isotope (e.g., (OS)-O-187/Os-188, He-3/He-4, Sr-87/Sr-86) records across this boundary have been established for six uplifted marine sections in Egypt, Spain and Denmark. The sections studied represent some of the stratigraphically most complete records across the onset of the carbon isotopic excursion (CIE) and associated benthic foraminifera extinctions that mark the Paleocene-Eocene boundary. High-sensitivity analyses failed to uncover evidence of extraterrestrial element or isotope enrichments in the six sections, refuting the hypothesis of a major comet impact at the boundary. Preliminary searches for other impact-indicative features, such as spherules or shocked quartz, also gave negative results. In the Danish section studied, three basaltic Ir-rich ash layers occur at the Paleocene-Eocene boundary, but no similar ashes were found in Egypt or Spain. The three ashes represent the earliest known manifestation of an unusual I to 2 million year long phase of explosive basaltic volcanism in the Faero-Greenland region. This volcanism is synchronous with major flood basalt effusions in East Greenland and is associated with prominent paleogeographic changes in the high-latitude North Atlantic region. Discharge of mantle-derived Os to seawater during this volcanism may explain a small decrease in (OS)-O-187/(OS)-O-188 ratio at the Paleocene-Eocene boundary in the Zumaya section in Spain. The environmental perturbations at the Paleocene-Eocene boundary appear to have been triggered by basaltic volcanism, but any model for the detailed causal relation remains speculative. (C) 2004 Elsevier B.V. All rights reserved.},
  author       = {Schmitz, Birger and Peucker-Ehrenbrink, B and Heilmann-Clausen, C and Aberg, G and Asaro, F and Lee, CTA},
  issn         = {1385-013X},
  keyword      = {osmium isotopes,iridium,flood basalt volcanism,comet impact,Paleocene-Eocene boundary,IETM,carbonisotopic excursion},
  language     = {eng},
  number       = {1-2},
  pages        = {1--17},
  publisher    = {Elsevier},
  series       = {Earth and Planetary Science Letters},
  title        = {Basaltic explosive volcanism, but no comet impact, at the Paleocene-Eocene boundary: high-resolution chemical and isotopic records from Egypt, Spain and Denmark},
  url          = {http://dx.doi.org/10.1016/j.epsl.2004.06.017},
  volume       = {225},
  year         = {2004},
}