Gigantic Ordovician volcanic ash fall in North America and Europe: Biological, tectonomagmatic, and event-stratigraphic significance

Research Article| October 01, 1992 Gigantic Ordovician volcanic ash fall in North America and Europe: Biological, tectonomagmatic, and event-stratigraphic significance Warren D. Huff; Warren D. Huff 1Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221 Search for other works by this author on: GSW Google Scholar Stig M. Bergström; Stig M. Bergström 2Department of Geological Sciences, Ohio State University, 125 S. Oval Mall, Columbus, Ohio 43210 Search for other works by this author on: GSW Google Scholar Dennis R. Kolata Dennis R. Kolata 3Illinois State Geological Survey, 615 E. Peabody Drive, Champaign, Illinois 61820 Search for other works by this author on: GSW Google Scholar Geology (1992) 20 (10): 875–878. https://doi.org/10.1130/0091-7613(1992)0202.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Warren D. Huff, Stig M. Bergström, Dennis R. Kolata; Gigantic Ordovician volcanic ash fall in North America and Europe: Biological, tectonomagmatic, and event-stratigraphic significance. Geology 1992;; 20 (10): 875–878. doi: https://doi.org/10.1130/0091-7613(1992)0202.3.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 Biostratigraphical, geochemical, isotopic, and paleogeographic data suggest that the Millbrig K-bentonite, one of the thickest and most widespread Ordovician volcanic ash beds in eastern North America, is the same as the so-called "Big Bentonite" in Baltoscandia. This is the first time that the same K-bentonite has been identified in both North America and Europe, and it serves as a unique event-stratigraphic marker over a large portion of the Northern Hemisphere. This eruption produced at least 340 km3of dense-rock-equivalent ash that was deposited in a layer up to 1-2 m thick over several million square kilometres. As much as 800 km3 of additional ash may have fallen into the Iapetus Ocean, for a total of 1140 km3. Trace element geochemistry shows that the ash was derived from a felsic cale-alkalic magmatic source characteristic of volcanism in a continental crust-based, destructive plate-margin setting. This is one of the largest, if not the largest, ash falls recorded in Earth's Phanerozoic stratigraphic record, but its recognizable effect on faunas and floras was minimal, and it did not result in a global extinction event. The Millbrig-Big Bentonite bed provides accurate time control for sedimentologic, paleoecologic, and paleogeographic reconstructions across plates positioned in tropical (Laurentia) and temperate (Baltica) latitudes during Middle Ordovician time. 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.