Authors
James H Wittke, James C Weaver, Ted E Bunch, James P Kennett, Douglas J Kennett, Andrew MT Moore, Gordon C Hillman, Kenneth B Tankersley, Albert C Goodyear, Christopher R Moore, I Randolph Daniel Jr, Jack H Ray, Neal H Lopinot, David Ferraro, Isabel Israde-Alcántara, James L Bischoff, Paul S DeCarli, Robert E Hermes, Johan B Kloosterman, Zsolt Revay, George A Howard, David R Kimbel, Gunther Kletetschka, Ladislav Nabelek, Carl P Lipo, Sachiko Sakai, Allen West, Richard B Firestone
Publication date
2013/6/4
Journal
Proceedings of the National Academy of Sciences
Volume
110
Issue
23
Pages
E2088-E2097
Publisher
National Academy of Sciences
Description
Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses …
Scholar articles
Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago
JH Wittke, JC Weaver, TE Bunch, JP Kennett… - Proceedings of the National Academy of Sciences, 2013