We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

Onset of main Phanerozoic marine radiation sparked by emerging Mid Ordovician icehouse.

Rasmussen, C. M. Ø. and Ullmann, C. V. and Jakobsen, K. G. and Lindskog, A. and Hansen, J. and Hansen, T. and Eriksson, M. E. and Dronov, A. and Frei, R. and Korte, C. and Nielsen, A. T. and Harper, D. A. T. (2016) 'Onset of main Phanerozoic marine radiation sparked by emerging Mid Ordovician icehouse.', Scientific reports., 6 . p. 18884.


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 δ13C 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.

Item Type:Article
Full text:(VoR) Version of Record
Available under License - Creative Commons Attribution.
Download PDF
Publisher Web site:
Publisher statement:This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit
Date accepted:30 November 2015
Date deposited:15 March 2016
Date of first online publication:06 January 2016
Date first made open access:15 March 2016

Save or Share this output

Look up in GoogleScholar