Research Article| April 01, 2010 Cometary airbursts and atmospheric chemistry: Tunguska and a candidate Younger Dryas event Adrian L. Melott; Adrian L. Melott 1Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045, USA Search for other works by this author on: GSW Google Scholar Brian C. Thomas; Brian C. Thomas 2Department of Physics and Astronomy, Washburn University, Topeka, Kansas 66621, USA Search for other works by this author on: GSW Google Scholar Gisela Dreschhoff; Gisela Dreschhoff 1Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045, USA Search for other works by this author on: GSW Google Scholar Carey K. Johnson Carey K. Johnson 3Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Adrian L. Melott 1Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045, USA Brian C. Thomas 2Department of Physics and Astronomy, Washburn University, Topeka, Kansas 66621, USA Gisela Dreschhoff 1Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045, USA Carey K. Johnson 3Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA Publisher: Geological Society of America Received: 07 Jul 2009 Revision Received: 28 Oct 2009 Accepted: 04 Nov 2009 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2010 Geological Society of America Geology (2010) 38 (4): 355–358. https://doi.org/10.1130/G30508.1 Article history Received: 07 Jul 2009 Revision Received: 28 Oct 2009 Accepted: 04 Nov 2009 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Adrian L. Melott, Brian C. Thomas, Gisela Dreschhoff, Carey K. Johnson; Cometary airbursts and atmospheric chemistry: Tunguska and a candidate Younger Dryas event. Geology 2010;; 38 (4): 355–358. doi: https://doi.org/10.1130/G30508.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract We find agreement between models of atmospheric chemistry changes from ionization for the A.D. 1908 Tunguska (Siberia region, Russia) airburst event and nitrate enhancement in Greenland Ice Sheet Project 2 (GISP2H and GISP2) ice cores, plus an unexplained ammonium spike. We then consider a candidate cometary impact at the Younger Dryas onset (YD). The large estimated NOx production and O3 depletion are beyond accurate extrapolation, but the ice core peak is much lower, possibly because of insufficient sampling resolution. Ammonium and nitrate spikes in both Greenland Ice Core Project (GRIP) and GISP2 ice cores have been attributed to biomass burning at the onset of the YD. A similar result is well resolved in Tunguska ice core data, but that forest fire was far too small to account for this. Direct input of ammonia from a comet into the atmosphere is adequate for YD ice core data, but not for the Tunguska data. An analog of the Haber process with hydrogen contributed by cometary or surface water, atmospheric nitrogen, high pressures, and possibly catalytic iron from a comet could in principle produce ammonia, accounting for the peaks in both data sets. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.