P. S. Decarli

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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(More)
It has been proposed that fragments of an asteroid or comet impacted Earth, deposited silica- and iron-rich microspherules and other proxies across several continents, and triggered the Younger Dryas cooling episode 12,900 years ago. Although many independent groups have confirmed the impact evidence, the hypothesis remains controversial because some groups(More)
We report the discovery in Lake Cuitzeo in central Mexico of a black, carbon-rich, lacustrine layer, containing nanodiamonds, microspherules, and other unusual materials that date to the early Younger Dryas and are interpreted to result from an extraterrestrial impact. These proxies were found in a 27-m-long core as part of an interdisciplinary effort to(More)
High-pressure minerals in meteorites provide clues for the impact processes that excavated, launched and delivered these samples to Earth. Most Martian meteorites are suggested to have been excavated from 3 to 7 km diameter impact craters. Here we show that the Tissint meteorite, a 2011 meteorite fall, contains virtually all the high-pressure phases (seven(More)
James H. Wittke, James C. Weaver, Ted E. Bunch, James P. Kennett, Douglas J. Kennett, Andrew M. T. 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.(More)
1. Introduction Ringwooodite, produced by shock metamorphism, is common in and adjacent to melt veins in highly shocked chondrites. Although ringwoodite can crystallize from the silicate melt in the shock-vein or pockets, most of the easily observed ringwoodite in shock veins is formed by the transformation of olivine in host-rock fragments entrained in the(More)
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