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Isotopic evidence of cool winter conditions in the mid-Piacenzian (Pliocene) of the southern North Sea Basin

Valentine, Annemarie; Johnson, Andrew L.A.; Leng, Melanie J.; Sloane, Hilary J.; Balson, Peter S.. 2011 Isotopic evidence of cool winter conditions in the mid-Piacenzian (Pliocene) of the southern North Sea Basin. Palaeogeography, Palaeoclimatology, Palaeoecology, 309 (1-2). 9-16. 10.1016/j.palaeo.2011.05.015

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Abstract/Summary

Oxygen isotope thermometry of Aequipecten opercularis and Atrina fragilis bivalves (which demonstrate all-year growth), provides quantitative evidence of cool-temperate winter conditions (below 10 °C) during deposition of the mid-Piacenzian Oorderen Sands and time-equivalent strata in the southern North Sea Basin (SNSB). Isotopic summer temperatures (seafloor) are within or only marginally above, the cool-temperate range (upper limit 20 °C). The occurrence of warm-temperate dinoflagellate cysts alongside (and presumably contemporaneous with) the bivalves, indicates the development of a correspondingly warm surface layer in summer (encystment allowing the dinoflagellates to survive cool winter conditions).This evidence of greater surface seasonality than now is consistent with greater global warmth and a reduction in the vigour of the Gulf Stream/North Atlantic Drift (GS/NAD), leading to a reduced supply of winter heat. This reduction in GS/NAD strength may be linked to breaching of the emerging Isthmus of Panama.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1016/j.palaeo.2011.05.015
Programmes: BGS Programmes 2010 > Marine Geoscience
ISSN: 0031-0182
Date made live: 02 Aug 2011 11:36
URI: http://nora.nerc.ac.uk/id/eprint/14809

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