Neo E.B. McAdams, Bradley D. Cramer, Alyssa M. Bancroft, Michael J. Melchin, Joseph A. Devera, James E. Day
· 2018
Abstract
Research Article| August 15, 2018 Integrated δ13Ccarb, conodont, and graptolite biochemostratigraphy of the Silurian from the Illinois Basin and stratigraphic revision of the Bainbridge Group Neo E.B. McAdams; Neo E.B. McAdams † 1Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa 52242, USA †Present address: Department of Geosciences, Texas Tech University, P.O. Box 41053, Lubbock, Texas 79409-1053, USA; neomcadams@gmail.com. Search for other works by this author on: GSW Google Scholar Bradley D. Cramer; Bradley D. Cramer 1Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa 52242, USA Search for other works by this author on: GSW Google Scholar Alyssa M. Bancroft; Alyssa M. Bancroft 2Indiana Geological and Water Survey, Indiana University, Bloomington, Indiana 47405, USA Search for other works by this author on: GSW Google Scholar Michael J. Melchin; Michael J. Melchin 3Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada Search for other works by this author on: GSW Google Scholar Joseph A. Devera; Joseph A. Devera 4Illinois State Geological Survey, Prairie Research Institute, University of Illinois, Champaign, Illinois 61820, USA Search for other works by this author on: GSW Google Scholar James E. Day James E. Day 5Department of Geography-Geology, Illinois State University, Normal, Illinois 61790, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Neo E.B. McAdams † 1Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa 52242, USA Bradley D. Cramer 1Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa 52242, USA Alyssa M. Bancroft 2Indiana Geological and Water Survey, Indiana University, Bloomington, Indiana 47405, USA Michael J. Melchin 3Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 2W5, Canada Joseph A. Devera 4Illinois State Geological Survey, Prairie Research Institute, University of Illinois, Champaign, Illinois 61820, USA James E. Day 5Department of Geography-Geology, Illinois State University, Normal, Illinois 61790, USA †Present address: Department of Geosciences, Texas Tech University, P.O. Box 41053, Lubbock, Texas 79409-1053, USA; neomcadams@gmail.com. Publisher: Geological Society of America Received: 14 Feb 2018 Revision Received: 31 May 2018 Accepted: 16 Jul 2018 First Online: 15 Aug 2018 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2018 Geological Society of America GSA Bulletin (2019) 131 (1-2): 335–352. https://doi.org/10.1130/B32033.1 Article history Received: 14 Feb 2018 Revision Received: 31 May 2018 Accepted: 16 Jul 2018 First Online: 15 Aug 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Neo E.B. McAdams, Bradley D. Cramer, Alyssa M. Bancroft, Michael J. Melchin, Joseph A. Devera, James E. Day; Integrated δ13Ccarb, conodont, and graptolite biochemostratigraphy of the Silurian from the Illinois Basin and stratigraphic revision of the Bainbridge Group. GSA Bulletin 2018;; 131 (1-2): 335–352. doi: https://doi.org/10.1130/B32033.1 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 SocietyGSA Bulletin Search Advanced Search Abstract The Illinois Basin of southwestern Illinois and southeastern Missouri contains one of the most extensive Silurian records in North America and is a potentially critical area for global sea-level and paleoclimatic/paleoceanographic studies. Unfortunately, the Silurian stratigraphy regionally remains understudied and often can only be correlated globally at series level. Silurian strata from southwestern Illinois and southeastern Missouri are currently assigned to the Sexton Creek Limestone, Seventy-Six Shale, St. Clair Limestone, and Moccasin Springs Formation. The latter three units are variously considered members of the Bainbridge Formation or formations within the Bainbridge Group. We advocate the formalization of the term Bainbridge at the group level throughout its area of use, composed of (in ascending order) the Seventy-Six Formation (raised in rank and geographically expanded herein), the St. Clair Formation (stratigraphically expanded herein), and the Moccasin Springs Formation with four members: the Greens Ferry, Sheppard Point, Lithium (proposed herein), and Randol members. The Bainbridge Group is unconformably underlain by the Silurian Sexton Creek Formation and conformably overlain by the ?Pridoli–Devonian Bailey Formation. Herein, additional nomenclatural changes are presented to the Cason Formation of Arkansas as well.Integrated carbon isotope (δ13C), conodont, and graptolite biochemostratigraphy of three localities in the southwestern Illinois and southeastern Missouri area indicate the presence of the early Sheinwoodian "Ireviken," Homerian "Mulde," and Ludfordian "Lau" positive carbon isotope excursions in the Bainbridge Group (the first published consecutive occurrence from North America). The stratigraphic revisions presented in this study provide a consistent and widely applicable lithostratigraphic nomenclature for the Bainbridge Group throughout its areal extent. This study also provides the first detailed integrated biochemostratigraphic record of all three major Wenlock–Ludfordian δ13C excursions from this important Laurentian basin, and it enables the first precise correlation of the Bainbridge Group into the global Silurian chronostratigraphic scheme. 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