Carbon isotope evidence for deep-water invasion at the Marjumiid-Pterocephaliid biomere boundary, Black Hills, USA: A common origin for biotic crises on Late Cambrian shelves

Abstract

Research Article| May 01, 1999 Carbon isotope evidence for deep-water invasion at the Marjumiid-Pterocephaliid biomere boundary, Black Hills, USA: A common origin for biotic crises on Late Cambrian shelves Patrick J. Perfetta; Patrick J. Perfetta 1Phillips Petroleum Company, 6330 West Loop South, Box 1967, Bellaire, Texas 77251-1967, USA Search for other works by this author on: GSW Google Scholar Kevin L. Shelton; Kevin L. Shelton 2Department of Geological Sciences, University of Missouri, Columbia, Missouri 65211, USA Search for other works by this author on: GSW Google Scholar James H. Stitt James H. Stitt 2Department of Geological Sciences, University of Missouri, Columbia, Missouri 65211, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Patrick J. Perfetta 1Phillips Petroleum Company, 6330 West Loop South, Box 1967, Bellaire, Texas 77251-1967, USA Kevin L. Shelton 2Department of Geological Sciences, University of Missouri, Columbia, Missouri 65211, USA James H. Stitt 2Department of Geological Sciences, University of Missouri, Columbia, Missouri 65211, USA Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1999) 27 (5): 403–406. https://doi.org/10.1130/0091-7613(1999)027<0403:CIEFDW>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 MailTo Tools Icon Tools Get Permissions Search Site Citation Patrick J. Perfetta, Kevin L. Shelton, James H. Stitt; Carbon isotope evidence for deep-water invasion at the Marjumiid-Pterocephaliid biomere boundary, Black Hills, USA: A common origin for biotic crises on Late Cambrian shelves. Geology 1999;; 27 (5): 403–406. doi: https://doi.org/10.1130/0091-7613(1999)027<0403:CIEFDW>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 An integrated carbon isotope, sedimentologic, and biostratigraphic study across a Late Cambrian mass-extinction boundary (Marjumiid-Pterocephaliid biomere boundary) in the Deadwood Formation, Black Hills, South Dakota, indicates invasion of the carbonate shelf by deep, cold, marine waters. Carbonate samples stratigraphically below the extinction boundary show an apparent trend of upwardly increasing δ13C values, from −0.4‰ to +0.1‰ and relate well to secular δ13C trends of Late Cambrian limestones. Coincident with the extinction horizon is a negative shift in δ13C values of 0.4‰ to 0.7‰. This shift can be attributed to introduction of cold, deep, 12C-enriched seawater accompanying invasion of opportunistic, cold-water trilobites onto depopulated shallow-water continental shelves. A similar abrupt negative shift in δ13C values has been observed at the suprajacent Pterocephaliid-Ptychaspid biomere boundary. Others have found that decreases in 87Sr/86Sr values synchronous with increases in δ13C values accompany renewed sea-level rise in this part of the Late Cambrian. Abrupt negative shifts in δ13C values at biomere boundaries require a companion process responsible for the extinction events. This process may be impingement of a shallow thermocline on the shelf or overturning of a stratified Cambrian ocean. Coupling of sea-level rise with location of the thermocline and shelf geometry may create conditions responsible for recurrent extinctions of shallow-shelf communities throughout the Late Cambrian. 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.