The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction
The onset of>1000 years of Younger Dryas cooling, broad-scale extinctions, and the disappearance of the Clovis culture in North America simultaneously occurred 12,900 years ago followed immediately by the appearance of a carbon-rich black layer at many locations. In situ bones of extinct megafaun...
Main Author: | |
---|---|
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Lawrence Berkeley National Laboratory
2009
|
Subjects: | |
Online Access: | https://digital.library.unt.edu/ark:/67531/metadc833059/ |
id |
ftunivnotexas:info:ark/67531/metadc833059 |
---|---|
record_format |
openpolar |
spelling |
ftunivnotexas:info:ark/67531/metadc833059 2023-05-15T16:35:33+02:00 The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction Firestone, Richard B. Lawrence Berkeley National Laboratory. Nuclear Science Division. 2009-10-26 30 Text https://digital.library.unt.edu/ark:/67531/metadc833059/ English eng Lawrence Berkeley National Laboratory rep-no: LBNL-4684E grantno: DE-AC02-05CH11231 osti: 1023382 https://digital.library.unt.edu/ark:/67531/metadc833059/ ark: ark:/67531/metadc833059 Journal Name: Journal of Cosmology; Journal Volume: 2; Related Information: Journal Publication Date: October 27, 2009 Charcoal 38 58 54 Carbon 14 37 Meteorites Soot Younger Dryas Extinctions Extraterrestrial Impacts Black Mat Clovis Mammoth Megafauna Belgium Isotope Dating Sediments Great Lakes Iridium Comets 07 Fullerenes Younger Dryas Archaeological Sites 59 Biological Extinction Polycyclic Aromatic Hydrocarbons North America 73 Diamonds 79 Article 2009 ftunivnotexas 2019-03-23T23:08:08Z The onset of>1000 years of Younger Dryas cooling, broad-scale extinctions, and the disappearance of the Clovis culture in North America simultaneously occurred 12,900 years ago followed immediately by the appearance of a carbon-rich black layer at many locations. In situ bones of extinct megafauna and Clovis tools occur only beneath this black layer and not within or above it. At the base of the black mat at 9 Clovis-age sites in North America and a site in Belgium numerous extraterrestrial impact markers were found including magnetic grains highly enriched in iridium, magnetic microspherules, vesicular carbon spherules enriched in cubic, hexagonal, and n-type nanodiamonds, glass-like carbon containing Fullerenes and nanodiamonds, charcoal, soot, and polycyclic aromatic hydrocarbons. The same impact markers were found mixed throughout the sediments of 15 Carolina Bays, elliptical depressions along the Atlantic coast, whose parallel major axes point towards either the Great Lakes or Hudson Bay. The magnetic grains and spherules have an unusual Fe/Ti composition similar to lunar Procellarum KREEP Terrane and the organic constituents are enriched in 14C leading to radiocarbon dates often well into the future. These characteristics are inconsistent with known meteorites and suggest that the impact was by a previous unobserved, possibly extrasolar body. The concentration of impact markers peaks near the Great Lakes and their unusually high water content suggests that a 4.6 km-wide comet fragmented and exploded over the Laurentide Ice Sheet creating numerous craters that now persist at the bottom of the Great Lakes. The coincidence of this impact, the onset of Younger Dryas cooling, extinction of the megafauna, and the appearance of a black mat strongly suggests that all these events are directly related. These results have unleashed an avalanche of controversy which I will address in this paper. Article in Journal/Newspaper Hudson Bay Ice Sheet University of North Texas: UNT Digital Library Hudson Hudson Bay |
institution |
Open Polar |
collection |
University of North Texas: UNT Digital Library |
op_collection_id |
ftunivnotexas |
language |
English |
topic |
Charcoal 38 58 54 Carbon 14 37 Meteorites Soot Younger Dryas Extinctions Extraterrestrial Impacts Black Mat Clovis Mammoth Megafauna Belgium Isotope Dating Sediments Great Lakes Iridium Comets 07 Fullerenes Younger Dryas Archaeological Sites 59 Biological Extinction Polycyclic Aromatic Hydrocarbons North America 73 Diamonds 79 |
spellingShingle |
Charcoal 38 58 54 Carbon 14 37 Meteorites Soot Younger Dryas Extinctions Extraterrestrial Impacts Black Mat Clovis Mammoth Megafauna Belgium Isotope Dating Sediments Great Lakes Iridium Comets 07 Fullerenes Younger Dryas Archaeological Sites 59 Biological Extinction Polycyclic Aromatic Hydrocarbons North America 73 Diamonds 79 Firestone, Richard B. The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction |
topic_facet |
Charcoal 38 58 54 Carbon 14 37 Meteorites Soot Younger Dryas Extinctions Extraterrestrial Impacts Black Mat Clovis Mammoth Megafauna Belgium Isotope Dating Sediments Great Lakes Iridium Comets 07 Fullerenes Younger Dryas Archaeological Sites 59 Biological Extinction Polycyclic Aromatic Hydrocarbons North America 73 Diamonds 79 |
description |
The onset of>1000 years of Younger Dryas cooling, broad-scale extinctions, and the disappearance of the Clovis culture in North America simultaneously occurred 12,900 years ago followed immediately by the appearance of a carbon-rich black layer at many locations. In situ bones of extinct megafauna and Clovis tools occur only beneath this black layer and not within or above it. At the base of the black mat at 9 Clovis-age sites in North America and a site in Belgium numerous extraterrestrial impact markers were found including magnetic grains highly enriched in iridium, magnetic microspherules, vesicular carbon spherules enriched in cubic, hexagonal, and n-type nanodiamonds, glass-like carbon containing Fullerenes and nanodiamonds, charcoal, soot, and polycyclic aromatic hydrocarbons. The same impact markers were found mixed throughout the sediments of 15 Carolina Bays, elliptical depressions along the Atlantic coast, whose parallel major axes point towards either the Great Lakes or Hudson Bay. The magnetic grains and spherules have an unusual Fe/Ti composition similar to lunar Procellarum KREEP Terrane and the organic constituents are enriched in 14C leading to radiocarbon dates often well into the future. These characteristics are inconsistent with known meteorites and suggest that the impact was by a previous unobserved, possibly extrasolar body. The concentration of impact markers peaks near the Great Lakes and their unusually high water content suggests that a 4.6 km-wide comet fragmented and exploded over the Laurentide Ice Sheet creating numerous craters that now persist at the bottom of the Great Lakes. The coincidence of this impact, the onset of Younger Dryas cooling, extinction of the megafauna, and the appearance of a black mat strongly suggests that all these events are directly related. These results have unleashed an avalanche of controversy which I will address in this paper. |
author2 |
Lawrence Berkeley National Laboratory. Nuclear Science Division. |
format |
Article in Journal/Newspaper |
author |
Firestone, Richard B. |
author_facet |
Firestone, Richard B. |
author_sort |
Firestone, Richard B. |
title |
The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction |
title_short |
The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction |
title_full |
The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction |
title_fullStr |
The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction |
title_full_unstemmed |
The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna and Clovis Extinction |
title_sort |
case for the younger dryas extraterrestrial impact event: mammoth, megafauna and clovis extinction |
publisher |
Lawrence Berkeley National Laboratory |
publishDate |
2009 |
url |
https://digital.library.unt.edu/ark:/67531/metadc833059/ |
geographic |
Hudson Hudson Bay |
geographic_facet |
Hudson Hudson Bay |
genre |
Hudson Bay Ice Sheet |
genre_facet |
Hudson Bay Ice Sheet |
op_source |
Journal Name: Journal of Cosmology; Journal Volume: 2; Related Information: Journal Publication Date: October 27, 2009 |
op_relation |
rep-no: LBNL-4684E grantno: DE-AC02-05CH11231 osti: 1023382 https://digital.library.unt.edu/ark:/67531/metadc833059/ ark: ark:/67531/metadc833059 |
_version_ |
1766025791629426688 |