Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions
Microtektites have been recovered from three horizons in eight middle Eocene to middle Oligocene marine sediment sequences. Five of these occurrences are coeval and of latest Eocene age (37.5 to 38.0 million years ago); three are coeval and of early late Eocene age (38.5 to 39.5 million years ago);...
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American Association for the Advancement of Science (AAAS)
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craaas:10.1126/science.221.4606.150 2024-06-09T07:39:43+00:00 Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions Keller, Gerta D'Hondt, Steven Vallier, Tracy L. 1983 http://dx.doi.org/10.1126/science.221.4606.150 https://www.science.org/doi/pdf/10.1126/science.221.4606.150 en eng American Association for the Advancement of Science (AAAS) Science volume 221, issue 4606, page 150-152 ISSN 0036-8075 1095-9203 journal-article 1983 craaas https://doi.org/10.1126/science.221.4606.150 2024-05-16T12:54:54Z Microtektites have been recovered from three horizons in eight middle Eocene to middle Oligocene marine sediment sequences. Five of these occurrences are coeval and of latest Eocene age (37.5 to 38.0 million years ago); three are coeval and of early late Eocene age (38.5 to 39.5 million years ago); and three are of middle Oligocene age (31 to 32 million years ago). In addition, rare probable microtektites have been found in sediments with ages of about 36.0 to 36.5 million years. The microtektite horizon at 37.5 to 38.0 million years can be correlated with the North American tektite-strewn field, which has a fission track age (minimum) of 34 to 35 million years and a paleomagnetic age of 37.5 to 38.0 million years. There is no evidence for mass faunal extinctions at any of the microtektite horizons. Many of the distinct faunal changes that occurred in the middle Eocene to middle Oligocene can be related to the formation of the Antarctic ice sheet and the associated cooling phenomena and intensification of bottom currents that led to large-scale dissolution of calcium carbonate and erosion, which created areally extensive hiatuses in the deep-sea sediment records. The occurrence of microtektite horizons of several ages and the lack of evidence for faunal extinctions suggest that the effects of extraterrestrial bolide impacts may be unimportant in the biologic realm during middle Eocene to middle Oligocene time. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet AAAS Resource Center (American Association for the Advancement of Science) Antarctic The Antarctic Science 221 4606 150 152 |
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AAAS Resource Center (American Association for the Advancement of Science) |
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English |
description |
Microtektites have been recovered from three horizons in eight middle Eocene to middle Oligocene marine sediment sequences. Five of these occurrences are coeval and of latest Eocene age (37.5 to 38.0 million years ago); three are coeval and of early late Eocene age (38.5 to 39.5 million years ago); and three are of middle Oligocene age (31 to 32 million years ago). In addition, rare probable microtektites have been found in sediments with ages of about 36.0 to 36.5 million years. The microtektite horizon at 37.5 to 38.0 million years can be correlated with the North American tektite-strewn field, which has a fission track age (minimum) of 34 to 35 million years and a paleomagnetic age of 37.5 to 38.0 million years. There is no evidence for mass faunal extinctions at any of the microtektite horizons. Many of the distinct faunal changes that occurred in the middle Eocene to middle Oligocene can be related to the formation of the Antarctic ice sheet and the associated cooling phenomena and intensification of bottom currents that led to large-scale dissolution of calcium carbonate and erosion, which created areally extensive hiatuses in the deep-sea sediment records. The occurrence of microtektite horizons of several ages and the lack of evidence for faunal extinctions suggest that the effects of extraterrestrial bolide impacts may be unimportant in the biologic realm during middle Eocene to middle Oligocene time. |
format |
Article in Journal/Newspaper |
author |
Keller, Gerta D'Hondt, Steven Vallier, Tracy L. |
spellingShingle |
Keller, Gerta D'Hondt, Steven Vallier, Tracy L. Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions |
author_facet |
Keller, Gerta D'Hondt, Steven Vallier, Tracy L. |
author_sort |
Keller, Gerta |
title |
Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions |
title_short |
Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions |
title_full |
Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions |
title_fullStr |
Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions |
title_full_unstemmed |
Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions |
title_sort |
multiple microtektite horizons in upper eocene marine sediments: no evidence for mass extinctions |
publisher |
American Association for the Advancement of Science (AAAS) |
publishDate |
1983 |
url |
http://dx.doi.org/10.1126/science.221.4606.150 https://www.science.org/doi/pdf/10.1126/science.221.4606.150 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_source |
Science volume 221, issue 4606, page 150-152 ISSN 0036-8075 1095-9203 |
op_doi |
https://doi.org/10.1126/science.221.4606.150 |
container_title |
Science |
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221 |
container_issue |
4606 |
container_start_page |
150 |
op_container_end_page |
152 |
_version_ |
1801381410058010624 |