End-cretaceous cooling and mass extinction driven by a dark cloud encounter
We have identified iridium in an ~5 m-thick section of pelagic sediment cored in the deep sea floor at Site 886C, in addition to a distinct spike in iridium at the K-Pg boundary related to the Chicxulub asteroid impact. We distinguish the contribution of the extraterrestrial matter in the sediments...
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ftdatacite:10.48550/arxiv.1603.06136 2023-05-15T16:41:28+02:00 End-cretaceous cooling and mass extinction driven by a dark cloud encounter Nimura, Tokuhiro Ebisuzaki, Toshikazu Maruyama, Shigenori 2016 https://dx.doi.org/10.48550/arxiv.1603.06136 https://arxiv.org/abs/1603.06136 unknown arXiv arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences Preprint Article article CreativeWork 2016 ftdatacite https://doi.org/10.48550/arxiv.1603.06136 2022-04-01T11:34:15Z We have identified iridium in an ~5 m-thick section of pelagic sediment cored in the deep sea floor at Site 886C, in addition to a distinct spike in iridium at the K-Pg boundary related to the Chicxulub asteroid impact. We distinguish the contribution of the extraterrestrial matter in the sediments from those of the terrestrial matter through a Co-Ir diagram, calling it the "extraterrestrial index" fEX. This new index reveals a broad iridium anomaly around the Chicxulub spike. Any mixtures of materials on the surface of the Earth cannot explain the broad iridium component. On the other hand, we find that an encounter of the solar system with a giant molecular cloud can aptly explain the component, especially if the molecular cloud has a size of ~100 pc and the central density of over 2000 protons/cm^3. Kataoka et al. (2013, 2014) pointed that an encounter with a dark cloud would drive an environmental catastrophe leading to mass extinction. Solid particles from the hypothesized dark cloud would combine with the global environment of Earth, remaining in the stratosphere for at least several months or years. With a sunshield effect estimated to be as large as -9.3 W m^-2, the dark cloud would have caused global climate cooling in the last 8 Myr of the Cretaceous period, consistent with the variations of stable isotope ratios in oxygen (Barrera and Huber, 1990; Li and Keller, 1998; Barrera and Savin, 1999; Li and Keller, 1999) and strontium (Barrera and Huber, 1990; Ingram, 1995; Sugarman et al., 1995). The resulting growth of the continental ice sheet also resulted in a regression of the sea level. The global cooling, which appears to be associated with a decrease in the diversity of fossils, eventually led to the mass extinction at the K-Pg boundary. : 7 pages, 8 figures, 2 tables Report Ice Sheet DataCite Metadata Store (German National Library of Science and Technology) Keller ENVELOPE(-58.406,-58.406,-62.073,-62.073) |
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Open Polar |
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DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences |
spellingShingle |
Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences Nimura, Tokuhiro Ebisuzaki, Toshikazu Maruyama, Shigenori End-cretaceous cooling and mass extinction driven by a dark cloud encounter |
topic_facet |
Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences |
description |
We have identified iridium in an ~5 m-thick section of pelagic sediment cored in the deep sea floor at Site 886C, in addition to a distinct spike in iridium at the K-Pg boundary related to the Chicxulub asteroid impact. We distinguish the contribution of the extraterrestrial matter in the sediments from those of the terrestrial matter through a Co-Ir diagram, calling it the "extraterrestrial index" fEX. This new index reveals a broad iridium anomaly around the Chicxulub spike. Any mixtures of materials on the surface of the Earth cannot explain the broad iridium component. On the other hand, we find that an encounter of the solar system with a giant molecular cloud can aptly explain the component, especially if the molecular cloud has a size of ~100 pc and the central density of over 2000 protons/cm^3. Kataoka et al. (2013, 2014) pointed that an encounter with a dark cloud would drive an environmental catastrophe leading to mass extinction. Solid particles from the hypothesized dark cloud would combine with the global environment of Earth, remaining in the stratosphere for at least several months or years. With a sunshield effect estimated to be as large as -9.3 W m^-2, the dark cloud would have caused global climate cooling in the last 8 Myr of the Cretaceous period, consistent with the variations of stable isotope ratios in oxygen (Barrera and Huber, 1990; Li and Keller, 1998; Barrera and Savin, 1999; Li and Keller, 1999) and strontium (Barrera and Huber, 1990; Ingram, 1995; Sugarman et al., 1995). The resulting growth of the continental ice sheet also resulted in a regression of the sea level. The global cooling, which appears to be associated with a decrease in the diversity of fossils, eventually led to the mass extinction at the K-Pg boundary. : 7 pages, 8 figures, 2 tables |
format |
Report |
author |
Nimura, Tokuhiro Ebisuzaki, Toshikazu Maruyama, Shigenori |
author_facet |
Nimura, Tokuhiro Ebisuzaki, Toshikazu Maruyama, Shigenori |
author_sort |
Nimura, Tokuhiro |
title |
End-cretaceous cooling and mass extinction driven by a dark cloud encounter |
title_short |
End-cretaceous cooling and mass extinction driven by a dark cloud encounter |
title_full |
End-cretaceous cooling and mass extinction driven by a dark cloud encounter |
title_fullStr |
End-cretaceous cooling and mass extinction driven by a dark cloud encounter |
title_full_unstemmed |
End-cretaceous cooling and mass extinction driven by a dark cloud encounter |
title_sort |
end-cretaceous cooling and mass extinction driven by a dark cloud encounter |
publisher |
arXiv |
publishDate |
2016 |
url |
https://dx.doi.org/10.48550/arxiv.1603.06136 https://arxiv.org/abs/1603.06136 |
long_lat |
ENVELOPE(-58.406,-58.406,-62.073,-62.073) |
geographic |
Keller |
geographic_facet |
Keller |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1603.06136 |
_version_ |
1766031912880570368 |