AffiliationUniv Arizona, Dept Anthropol
Univ Arizona, Dept Geosci
MetadataShow full item record
PublisherPublic Library of Science
CitationA Blind Test of the Younger Dryas Impact Hypothesis 2016, 11 (7):e0155470 PLOS ONE
Rights© 2016 Holliday et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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AbstractThe Younger Dryas Impact Hypothesis (YDIH) states that North America was devastated by some sort of extraterrestrial event similar to 12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB), i.e., similar to 12.8k cal yrs BP? A test reported here presents the results of analyses that address these questions. Two different labs analyzed identical splits of samples collected at, above, and below the similar to 12.8ka zone at the Lubbock Lake archaeological site (LL) in northwest Texas. Both labs reported similar variation in levels of magnetic micrograins (>300 mg/kg >12.8ka and <11.5ka, but <150 mg/kg 12.8ka to 11.5ka). Analysis for magnetic microspheres in one split, reported elsewhere, produced very low to nonexistent levels throughout the section. In the other split, reported here, the levels of magnetic microspherules and nanodiamonds are low or nonexistent at, below, and above the YDB with the notable exception of a sample <11,500 cal years old. In that sample the claimed impact proxies were recovered at abundances two to four orders of magnitude above that from the other samples. Reproducibility of at least some analyses are problematic. In particular, no standard criteria exist for identification of magnetic spheres. Moreover, the purported impact proxies are not unique to the YDB.
NoteOpen Access Journal
VersionFinal published version
SponsorsArgonaut Archaeological Research Fund University of Arizona; College of Arts and Sciences, University of Wyoming