Significant Southern Ocean warming event in the late middle Eocene

Abstract

Research Article| November 01, 2003 Significant Southern Ocean warming event in the late middle Eocene Steven M. Bohaty; Steven M. Bohaty 1Earth Sciences Department, University of California, Santa Cruz, California 95064, USA Search for other works by this author on: GSW Google Scholar James C. Zachos James C. Zachos 1Earth Sciences Department, University of California, Santa Cruz, California 95064, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Steven M. Bohaty 1Earth Sciences Department, University of California, Santa Cruz, California 95064, USA James C. Zachos 1Earth Sciences Department, University of California, Santa Cruz, California 95064, USA Publisher: Geological Society of America Received: 20 May 2003 Revision Received: 21 Jul 2003 Accepted: 22 Jul 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2003) 31 (11): 1017–1020. https://doi.org/10.1130/G19800.1 Article history Received: 20 May 2003 Revision Received: 21 Jul 2003 Accepted: 22 Jul 2003 First Online: 02 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 Steven M. Bohaty, James C. Zachos; Significant Southern Ocean warming event in the late middle Eocene. Geology 2003;; 31 (11): 1017–1020. doi: https://doi.org/10.1130/G19800.1 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 A prominent middle Eocene warming event is identified in Southern Ocean deep-sea cores, indicating that long-term cooling through the middle and late Eocene was not monotonic. At sites on Maud Rise and the Kerguelen Plateau, a distinct negative shift in δ18O values (∼1.0‰) is observed ca. 41.5 Ma. This excursion is interpreted as primarily a temperature signal, with a transient warming of 4 °C over 600 k.y. affecting both surface and middle-bathyal deep waters in the Indian-Atlantic region of the Southern Ocean. This isotopic event is designated as the middle Eocene climatic optimum, and is interpreted to represent a significant climatic reversal in the midst of middle to late Eocene deep-sea cooling. The lack of a significant negative carbon isotope excursion, as observed during the Paleocene–Eocene thermal maximum, and the gradual rate of high-latitude warming suggest that this event was not triggered by methane hydrate dissociation. Rather, a transient rise in pCO2 levels is suspected, possibly as a result of metamorphic decarbonation in the Himalayan orogen or increased ridge/arc volcanism during the late middle Eocene. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.