Mass mortality and extraterrestrial impacts
The discovery of iridium enrichment at the Cretaceous/Tertiary boundary resulted in formulation of hypothesis of a cometary or asteroid impact as the cause of the biological extinctions at this boundary. Subsequent discoveries of geochemical anomalies at major stratigraphic boundaries like the Preca...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19890011964 2023-05-15T17:13:13+02:00 Mass mortality and extraterrestrial impacts Pierre-Aubry, M. Gradstein, F. M. Jansa, L. F. Unclassified, Unlimited, Publicly available JAN 1, 1988 application/pdf http://hdl.handle.net/2060/19890011964 unknown Document ID: 19890011964 Accession ID: 89N21335 http://hdl.handle.net/2060/19890011964 No Copyright CASI ENVIRONMENT POLLUTION Lunar and Planetary Inst., Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality; p 85-86 1988 ftnasantrs 2015-03-15T05:57:13Z The discovery of iridium enrichment at the Cretaceous/Tertiary boundary resulted in formulation of hypothesis of a cometary or asteroid impact as the cause of the biological extinctions at this boundary. Subsequent discoveries of geochemical anomalies at major stratigraphic boundaries like the Precambrian/Cambrian, Permian/Triassic, Middle/Late Jurassic, resulted in the application of similar extraterrestrial impact theories to explain biological changes at these boundaries. Until recently the major physical evidence, as is the location of the impact crater site, to test the impact induced biological extinction was lacking. The diameter of such a crater would be in the range of 60 to 100 km. The recent discovery of the first impact crater in the ocean provide the first opportunity to test the above theory. The crater, named Montagnais and located on the outer shelf off Nova Scotia, Canada, has a minimum diameter of 42 km, with some evidence to a diameter of more than 60 km. At the Montagnais impact site, micropaleontological analysis of the uppermost 80 m of the fall-back breccia represented by a mixture of pre-impact sediments and basement rocks which fills the crater and of the basal 50 m of post-impact marine sediments which overly the impact deposits, revealed presence of diversified foraminiferal and nannoplankton assemblages. The sediments which are intercalated within the uppermost part of the fall-back breccia, had to be deposited before the meteorite impact. The post-impact deposits were laid down almost immediately after the impact as also supported by the micropaleontological data. In conclusion, micropaleontological studies of sediments from the first submarine impact crater site identified in the ocean did not reveal any mass extinction or significant biological changes at the impact site or in the proximal deep ocean basin. Other/Unknown Material montagnais NASA Technical Reports Server (NTRS) Canada |
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ENVIRONMENT POLLUTION |
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ENVIRONMENT POLLUTION Pierre-Aubry, M. Gradstein, F. M. Jansa, L. F. Mass mortality and extraterrestrial impacts |
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ENVIRONMENT POLLUTION |
description |
The discovery of iridium enrichment at the Cretaceous/Tertiary boundary resulted in formulation of hypothesis of a cometary or asteroid impact as the cause of the biological extinctions at this boundary. Subsequent discoveries of geochemical anomalies at major stratigraphic boundaries like the Precambrian/Cambrian, Permian/Triassic, Middle/Late Jurassic, resulted in the application of similar extraterrestrial impact theories to explain biological changes at these boundaries. Until recently the major physical evidence, as is the location of the impact crater site, to test the impact induced biological extinction was lacking. The diameter of such a crater would be in the range of 60 to 100 km. The recent discovery of the first impact crater in the ocean provide the first opportunity to test the above theory. The crater, named Montagnais and located on the outer shelf off Nova Scotia, Canada, has a minimum diameter of 42 km, with some evidence to a diameter of more than 60 km. At the Montagnais impact site, micropaleontological analysis of the uppermost 80 m of the fall-back breccia represented by a mixture of pre-impact sediments and basement rocks which fills the crater and of the basal 50 m of post-impact marine sediments which overly the impact deposits, revealed presence of diversified foraminiferal and nannoplankton assemblages. The sediments which are intercalated within the uppermost part of the fall-back breccia, had to be deposited before the meteorite impact. The post-impact deposits were laid down almost immediately after the impact as also supported by the micropaleontological data. In conclusion, micropaleontological studies of sediments from the first submarine impact crater site identified in the ocean did not reveal any mass extinction or significant biological changes at the impact site or in the proximal deep ocean basin. |
format |
Other/Unknown Material |
author |
Pierre-Aubry, M. Gradstein, F. M. Jansa, L. F. |
author_facet |
Pierre-Aubry, M. Gradstein, F. M. Jansa, L. F. |
author_sort |
Pierre-Aubry, M. |
title |
Mass mortality and extraterrestrial impacts |
title_short |
Mass mortality and extraterrestrial impacts |
title_full |
Mass mortality and extraterrestrial impacts |
title_fullStr |
Mass mortality and extraterrestrial impacts |
title_full_unstemmed |
Mass mortality and extraterrestrial impacts |
title_sort |
mass mortality and extraterrestrial impacts |
publishDate |
1988 |
url |
http://hdl.handle.net/2060/19890011964 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Canada |
geographic_facet |
Canada |
genre |
montagnais |
genre_facet |
montagnais |
op_source |
CASI |
op_relation |
Document ID: 19890011964 Accession ID: 89N21335 http://hdl.handle.net/2060/19890011964 |
op_rights |
No Copyright |
_version_ |
1766070143419416576 |