Composition of biotite phenocrysts in Ordovician tephras casts doubt on the proposed trans-Atlantic correlation of the Millbrig K-bentonite (United States) and the Kinnekulle K-bentonite (Sweden)

Abstract

Research Article| September 01, 1995 Composition of biotite phenocrysts in Ordovician tephras casts doubt on the proposed trans-Atlantic correlation of the Millbrig K-bentonite (United States) and the Kinnekulle K-bentonite (Sweden) John T. Haynes; John T. Haynes 1Department of Mineral Sciences, National Museum of Natural History, MRC-119, Smithsonian Institution, Washington, D.C. 20560 Search for other works by this author on: GSW Google Scholar William G. Melson; William G. Melson 1Department of Mineral Sciences, National Museum of Natural History, MRC-119, Smithsonian Institution, Washington, D.C. 20560 Search for other works by this author on: GSW Google Scholar Michael J. Kunk Michael J. Kunk 2U.S. Geological Survey, MS-981, National Center, Reston, Virginia 22092 Search for other works by this author on: GSW Google Scholar Author and Article Information John T. Haynes 1Department of Mineral Sciences, National Museum of Natural History, MRC-119, Smithsonian Institution, Washington, D.C. 20560 William G. Melson 1Department of Mineral Sciences, National Museum of Natural History, MRC-119, Smithsonian Institution, Washington, D.C. 20560 Michael J. Kunk 2U.S. Geological Survey, MS-981, National Center, Reston, Virginia 22092 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1995) 23 (9): 847–850. https://doi.org/10.1130/0091-7613(1995)023<0847:COBPIO>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation John T. Haynes, William G. Melson, Michael J. Kunk; Composition of biotite phenocrysts in Ordovician tephras casts doubt on the proposed trans-Atlantic correlation of the Millbrig K-bentonite (United States) and the Kinnekulle K-bentonite (Sweden). Geology 1995;; 23 (9): 847–850. doi: https://doi.org/10.1130/0091-7613(1995)023<0847:COBPIO>2.3.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 Biotite phenocryst compositions in three thick, widespread Ordovician K-bentonites, the Deicke and Millbrig from Big Ridge, Alabama, and the Kinnekulle from Mossen, Västergötland, Sweden, fall into three distinct groups, and so the proposed intercontinental correlation of the Millbrig and the Kinnekulle is suspect. Because the biotites are nearly pristine compositionally, electron microprobe analyses provide a precise geochemical fingerprint of each bed. Millbrig and Kinnekulle biotites contain more FeO* and MnO and less MgO and TiO2 than do Deicke biotites. Millbrig biotites contain more MgO and less TiO2 than Kinnekulle biotites, and Kinnekulle biotites contain appreciably more Al2O3 than either Deicke or Millbrig biotites. Each of these tephras was unmistakably the product of a gigantic explosive volcanic eruption, but the differences in phenocryst chemistry point to derivation from three compositionally different magma batches. 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.