Spheroids at the Cretaceous-Tertiary boundary are altered impact droplets of basaltic composition

Research Article| November 01, 1983 Spheroids at the Cretaceous-Tertiary boundary are altered impact droplets of basaltic composition Alessandro Montanari; Alessandro Montanari 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Richard L. Hay; Richard L. Hay 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Walter Alvarez; Walter Alvarez 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Frank Asaro; Frank Asaro 2Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Helen V. Michel; Helen V. Michel 2Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Luis W. Alvarez; Luis W. Alvarez 2Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Jan Smit Jan Smit 3Geological Institute, University of Amsterdam, Nieuwe Prinsengracht 130 1018 VZ Amsterdam, Netherlands Search for other works by this author on: GSW Google Scholar Author and Article Information Alessandro Montanari 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Richard L. Hay 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Walter Alvarez 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Frank Asaro 2Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 Helen V. Michel 2Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 Luis W. Alvarez 2Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 Jan Smit 3Geological Institute, University of Amsterdam, Nieuwe Prinsengracht 130 1018 VZ Amsterdam, Netherlands Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1983) 11 (11): 668–671. https://doi.org/10.1130/0091-7613(1983)11<668:SATCBA>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Alessandro Montanari, Richard L. Hay, Walter Alvarez, Frank Asaro, Helen V. Michel, Luis W. Alvarez, Jan Smit; Spheroids at the Cretaceous-Tertiary boundary are altered impact droplets of basaltic composition. Geology 1983;; 11 (11): 668–671. doi: https://doi.org/10.1130/0091-7613(1983)11<668:SATCBA>2.0.CO;2 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 Sand-size spheroids of K-feldspar in the Cretaceous-Tertiary (C-T) boundary clay at Caravaca, southern Spain, were interpreted by Smit and Klaver as having solidified from a melt resulting from the impact of a large extraterrestrial body. Sand-size spheroids of K-feldspar, glauconite, and magnetite-quartz have been found in the C-T bondary clay in northern Italy, and spheroids of K-feldspar and pyrite were found in the boundary clay at Deep Sea Drilling Project Site 465A, in the central Pacific. These spheroids have textures similar to those of rapidly crystallized feldspar and mafic silicates. They are interpreted as diagenetically altered microcrystalline spherules of basaltic composition produced by the impact of a large asteroid in an ocean basin at the end of the Cretaceous. They are analogous to the glassy microtektites produced by impacts on more siliceous target rocks. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.