Decoupling of the carbon cycle during Ocean Anoxic Event 2

Abstract

Research Article| July 01, 2014 Decoupling of the carbon cycle during Ocean Anoxic Event 2 James S. Eldrett; James S. Eldrett * Shell International Exploration and Production Inc., Shell Houston Technology Center, 3333 Highway 6 South, Houston, Texas 77082, USA *E-mail: [e-mail]. Search for other works by this author on: GSW Google Scholar Daniel Minisini; Daniel Minisini Shell International Exploration and Production Inc., Shell Houston Technology Center, 3333 Highway 6 South, Houston, Texas 77082, USA Search for other works by this author on: GSW Google Scholar Steven C. Bergman Steven C. Bergman Shell International Exploration and Production Inc., Shell Houston Technology Center, 3333 Highway 6 South, Houston, Texas 77082, USA Search for other works by this author on: GSW Google Scholar Geology (2014) 42 (7): 567–570. https://doi.org/10.1130/G35520.1 Article history received: 29 Jan 2014 rev-recd: 31 Mar 2014 accepted: 01 Apr 2014 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation James S. Eldrett, Daniel Minisini, Steven C. Bergman; Decoupling of the carbon cycle during Ocean Anoxic Event 2. Geology 2014;; 42 (7): 567–570. doi: https://doi.org/10.1130/G35520.1 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 SocietyGeology Search Advanced Search Abstract The Cenomanian to Turonian boundary transition (ca. 95–93 Ma) represents one of the most profound global perturbations in the carbon cycle of the past 140 m.y. This interval is characterized by widespread deposition of organic-rich fine-grained sediment marked by a globally recognized positive carbon isotope excursion (CIE) reflecting the widespread removal of 12C-enriched organic matter in marine sediments under global anoxic greenhouse conditions. However, the exact timing and trigger of this inferred global phenomenon, termed Oceanic Anoxic Event 2 (OAE-2), is still debated, with recent studies showing diachroneity between the deposition of the organic-rich sediment and the CIE, and conflicting interpretations on detailed redox analyses in several of these inferred anoxic settings. Here we present the first evidence for widespread and persistent oxygenation during OAE-2 based primarily on the distribution of redox-sensitive trace metals and biota preserved in sedimentary rocks from the Western Interior Seaway of North America. Our data indicate anoxic-euxinic conditions in the mid- to late Cenomanian, but improved bottom-water oxygenation prior to and during the CIE. Trace metal enrichments support large volumes of mafic volcanism possibly from the High Arctic large igneous province (HALIP), which occur within the middle of the CIE indicating that the emplacement of LIPs was not the primary trigger of the Cenomanian-Turonian CIE. The apparent paradox of an oxygenated phase within OAE-2 suggests a much more complex carbon cycle during these global perturbations than previously thought. These findings have important implications for greenhouse carbon cycle changes over time scales of 0.1–10 m.y. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.