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Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling

Overview of attention for article published in Proceedings of the National Academy of Sciences of the United States of America, September 2007
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About this Attention Score

  • In the top 5% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (99th percentile)
  • High Attention Score compared to outputs of the same age and source (99th percentile)

Mentioned by

news
42 news outlets
blogs
16 blogs
policy
1 policy source
twitter
77 tweeters
facebook
8 Facebook pages
wikipedia
5 Wikipedia pages
googleplus
3 Google+ users
reddit
1 Redditor
pinterest
1 Pinner
video
3 video uploaders

Citations

dimensions_citation
311 Dimensions

Readers on

mendeley
671 Mendeley
citeulike
4 CiteULike
connotea
3 Connotea
Title
Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling
Published in
Proceedings of the National Academy of Sciences of the United States of America, September 2007
DOI 10.1073/pnas.0706977104
Pubmed ID
Authors

R. B. Firestone, A. West, J. P. Kennett, L. Becker, T. E. Bunch, Z. S. Revay, P. H. Schultz, T. Belgya, D. J. Kennett, J. M. Erlandson, O. J. Dickenson, A. C. Goodyear, R. S. Harris, G. A. Howard, J. B. Kloosterman, P. Lechler, P. A. Mayewski, J. Montgomery, R. Poreda, T. Darrah, S. S. Q. Hee, A. R. Smith, A. Stich, W. Topping, J. H. Wittke, W. S. Wolbach

Abstract

A carbon-rich black layer, dating to approximately 12.9 ka, has been previously identified at approximately 50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at approximately equal 12.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at approximately 12.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.

Twitter Demographics

The data shown below were collected from the profiles of 77 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 671 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
United States 32 5%
Canada 5 <1%
Brazil 5 <1%
Germany 4 <1%
Chile 4 <1%
United Kingdom 3 <1%
Belgium 3 <1%
Italy 2 <1%
Australia 2 <1%
Other 21 3%
Unknown 590 88%

Demographic breakdown

Readers by professional status Count As %
Student > Ph. D. Student 161 24%
Researcher 121 18%
Student > Bachelor 102 15%
Student > Master 85 13%
Professor 39 6%
Other 131 20%
Unknown 32 5%
Readers by discipline Count As %
Earth and Planetary Sciences 271 40%
Agricultural and Biological Sciences 118 18%
Environmental Science 80 12%
Social Sciences 73 11%
Arts and Humanities 34 5%
Other 41 6%
Unknown 54 8%

Attention Score in Context

This research output has an Altmetric Attention Score of 527. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 12 December 2019.
All research outputs
#16,615
of 14,354,509 outputs
Outputs from Proceedings of the National Academy of Sciences of the United States of America
#544
of 82,385 outputs
Outputs of similar age
#16,159
of 13,563,188 outputs
Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#543
of 82,187 outputs
Altmetric has tracked 14,354,509 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 99th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 82,385 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 25.6. This one has done particularly well, scoring higher than 99% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 13,563,188 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 99% of its contemporaries.
We're also able to compare this research output to 82,187 others from the same source and published within six weeks on either side of this one. This one has done particularly well, scoring higher than 99% of its contemporaries.