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Onset of main Phanerozoic marine radiation sparked by emerging Mid Ordovician icehouse.
Rasmussen, Christian M Ø; Ullmann, Clemens V; Jakobsen, Kristian G; Lindskog, Anders; Hansen, Jesper; Hansen, Thomas; Eriksson, Mats E; Dronov, Andrei; Frei, Robert; Korte, Christoph; Nielsen, Arne T; Harper, David A T.
Affiliation
  • Rasmussen CM; Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen K, Denmark.
  • Ullmann CV; Department of Geology, Lund University, Sölvegatan 12, S-223 62 Lund, Sweden.
  • Jakobsen KG; Center for Macroecology, Evolution and Climate, University of Copenhagen.
  • Lindskog A; Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark.
  • Hansen J; Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, U.K.
  • Hansen T; Ministry of Mineral Resources, Maneq 1A, 201, P.O. Box 930, 3900 Nuuk, Greenland.
  • Eriksson ME; Department of Geology, Lund University, Sölvegatan 12, S-223 62 Lund, Sweden.
  • Dronov A; Akvaplan-Niva, High North Research Centre 9296 Tromsø, Norway.
  • Frei R; Akvaplan-Niva, High North Research Centre 9296 Tromsø, Norway.
  • Korte C; Department of Geology, Lund University, Sölvegatan 12, S-223 62 Lund, Sweden.
  • Nielsen AT; Geological Institute of the Russian Academy of Sciences, Moscow, Russian Federation.
  • Harper DA; Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark.
Sci Rep ; 6: 18884, 2016 Jan 06.
Article in En | MEDLINE | ID: mdl-26733399
ABSTRACT
The Great Ordovician Biodiversification Event (GOBE) was the most rapid and sustained increase in marine Phanerozoic biodiversity. What generated this biotic response across Palaeozoic seascapes is a matter of debate; several intrinsic and extrinsic drivers have been suggested. One is Ordovician climate, which in recent years has undergone a paradigm shift from a text-book example of an extended greenhouse to an interval with transient cooling intervals - at least during the Late Ordovician. Here, we show the first unambiguous evidence for a sudden Mid Ordovician icehouse, comparable in magnitude to the Quaternary glaciations. We further demonstrate the initiation of this icehouse to coincide with the onset of the GOBE. This finding is based on both abiotic and biotic proxies obtained from the most comprehensive geochemical and palaeobiological dataset yet collected through this interval. We argue that the icehouse conditions increased latitudinal and bathymetrical temperature and oxygen gradients initiating an Early Palaeozoic Great Ocean Conveyor Belt. This fuelled the GOBE, as upwelling zones created new ecospace for the primary producers. A subsequent rise in δ(13)C ratios known as the Middle Darriwilian Isotopic Carbon Excursion (MDICE) may reflect a global response to increased bioproductivity encouraged by the onset of the GOBE.
Subject(s)

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Radiation / Ecosystem / Biodiversity / Aquatic Organisms Type of study: Prognostic_studies Language: En Journal: Sci Rep Year: 2016 Document type: Article Affiliation country: Denmark

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Radiation / Ecosystem / Biodiversity / Aquatic Organisms Type of study: Prognostic_studies Language: En Journal: Sci Rep Year: 2016 Document type: Article Affiliation country: Denmark