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Major shifts in calcareous phytoplankton assemblages through the Eocene-Oligocene transition of Tanzania and their implications for low-latitude primary production

Dunkley Jones, T; Bown, PR; Pearson, PN; Wade, BS; Coxall, HK; Lear, CH; (2008) Major shifts in calcareous phytoplankton assemblages through the Eocene-Oligocene transition of Tanzania and their implications for low-latitude primary production. Paleoceanography , 23 (4) , Article PA4204. 10.1029/2008PA001640. Green open access

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Abstract

A high-resolution record of exceptionally well preserved calcareous nannofossil assemblages from Tanzania is marked by two key transitions closely related to the climatic events of the Eocene-Oligocene transition (EOT). The first transition, at similar to 34.0 Ma, precedes the first positive shift in delta O-18 and coincides with a distinct interval of very low nannofossil abundance and a cooling in sea surface temperatures (SST). The second, at similar to 33.63 Ma, is immediately above the Eocene-Oligocene boundary (EOB) and is associated with a significant drop in nannofossil diversity. Both transitions involve significant reductions in the abundance of holococcoliths and other oligotrophic taxa. These changes in calcareous phytoplankton assemblages indicate (1) a widespread and significant perturbation to the low-latitude surface ocean closely tied to the EOB, (2) a potential role for reduced carbonate primary production at the onset of global cooling, and (3) a significant increase in nutrient availability in the low-latitude surface ocean through the EOT.

Type:Article
Title:Major shifts in calcareous phytoplankton assemblages through the Eocene-Oligocene transition of Tanzania and their implications for low-latitude primary production
Open access status:An open access version is available from UCL Discovery
DOI:10.1029/2008PA001640
Publisher version:http://dx.doi.org/10.1029/2008PA001640
Language:English
Additional information:Copyright 2008 by the American Geophysical Union
Keywords:Indian-ocean, Atlantic-ocean, Eocene/oligocene boundary, Antarctic glaciation, Earliest oligocene, Coastal Tanzania, Thermal maximum, Stable-isotope, Climate-change, Nannofossil assemblages
UCL classification:UCL > School of Arts and Social Sciences > Faculty of Social and Historical Sciences > Geography
UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Earth Sciences

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