Extinction and environmental change across the Eocene-Oligocene boundary in Tanzania

Pearson, Paul Nicholas ORCID: https://orcid.org/0000-0003-4628-9818, McMillan, Ian Kenneth, Wade, Bridget S., Jones, Tom Dunkley, Coxall, Helen Kathrine, Bown, Paul R. and Lear, Caroline Helen ORCID: https://orcid.org/0000-0002-7533-4430 2008. Extinction and environmental change across the Eocene-Oligocene boundary in Tanzania. Geology 36 (2) , pp. 179-182. 10.1130/G24308A.1

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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 ∼34.0 Ma, precedes the first positive shift in δ 18O and coincides with a distinct interval of very low nannofossil abundance and a cooling in sea surface temperatures (SST). The second, at ∼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.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	G Geography. Anthropology. Recreation > GC Oceanography Q Science > QE Geology
Uncontrolled Keywords:	mass extinction; Eocene; Oligocene; foraminifera; nannofossils
Publisher:	Geological Society of America
ISSN:	0091-7613
Last Modified:	11 May 2023 19:57
URI:	https://orca.cardiff.ac.uk/id/eprint/10120

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