Valanginian Weissert oceanic anoxic event

Abstract

Research Article| February 01, 2004 Valanginian Weissert oceanic anoxic event Elisabetta Erba; Elisabetta Erba 1Dipartimento di Scienze della Terra "A.Desio," Università degli Studi di Milano, via Mangiagalli, 34, 20133 Milano, Italy Search for other works by this author on: GSW Google Scholar Annachiara Bartolini; Annachiara Bartolini 2R 32 du Centre National de la Recherche Scientifique, Micropaléontologie, case 104, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris 05, France Search for other works by this author on: GSW Google Scholar Roger L. Larson Roger L. Larson 3Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Elisabetta Erba 1Dipartimento di Scienze della Terra "A.Desio," Università degli Studi di Milano, via Mangiagalli, 34, 20133 Milano, Italy Annachiara Bartolini 2R 32 du Centre National de la Recherche Scientifique, Micropaléontologie, case 104, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris 05, France Roger L. Larson 3Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA Publisher: Geological Society of America Received: 16 Jul 2003 Revision Received: 20 Oct 2003 Accepted: 21 Oct 2003 First Online: 03 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2004) 32 (2): 149–152. https://doi.org/10.1130/G20008.1 Article history Received: 16 Jul 2003 Revision Received: 20 Oct 2003 Accepted: 21 Oct 2003 First Online: 03 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 Elisabetta Erba, Annachiara Bartolini, Roger L. Larson; Valanginian Weissert oceanic anoxic event. Geology 2004;; 32 (2): 149–152. doi: https://doi.org/10.1130/G20008.1 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 Biotic changes in nannofossils and radiolarians associated with the Valanginian δ13C anomaly are documented at Ocean Drilling Program Hole 1149B in the Pacific Ocean: they are coeval and similar to those previously documented in the Tethys, suggesting a global perturbation of marine ecosystems. A marked increase in abundance of Diazomatolithus, absence of nannoconids, and a Pantanellium peak characterize the Valanginian δ13C excursion. Such changes are interpreted as being due to global enhanced fertility and a biocalcification crisis under conditions of excess CO2. The occurrence of organic C–rich black shales in the Southern Alps and in the Pacific in the interval corresponding to the δ13C excursion suggests a Valanginian oceanic anoxic event (OAE). Volcanism of the Paranà-Etendeka large igneous province (ca. 132 Ma) was presumably responsible for an increase of CO2, triggering a climate change and accelerated hydrological cycling, possibly causing an indirect fertilization of the oceans. Widespread nutrification via introduction of biolimiting metals at spreading ridges could have significantly increased during the Gondwana breakup and simultaneous tectonic events in three separate oceans. There is no paleontological or δ18O evidence of warming during the Valanginian OAE. On the contrary, both nannofossils and oxygen isotopes record a cooling event at the climax of the δ13C excursion. Weathering of basalts and burial of organic C–rich black shales were presumably responsible for CO2 drawdown and establishment of reversed greenhouse conditions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.