Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Planktonic foraminiferal turnover, diversity fluctuations and geochemical signals across the Eocene/Oligocene boundary in Tanzania

Wade, Bridget S. and Pearson, Paul Nicholas 2008. Planktonic foraminiferal turnover, diversity fluctuations and geochemical signals across the Eocene/Oligocene boundary in Tanzania. Marine Micropaleontology 68 (3-4) , pp. 244-255. 10.1016/j.marmicro.2008.04.002

Full text not available from this repository.


A major turnover in planktonic foraminifera occurred across the Eocene/Oligocene (E/O) boundary. New drill holes through the E/O boundary in southern Tanzania contain extremely well-preserved and diverse assemblages of planktonic foraminifera. Here we document a 1.2 million year record of assemblages, diversity and stable isotope fluctuations through this critical interval, which is often dissolved and/or recrystallised in carbonate-rich facies. The E/O boundary is marked by the abrupt extinction of all five remaining species of the family Hantkeninidae and a distinct size reduction in the genus Pseudohastigerina. The boundary is preceded over a short stratigraphic interval by the extinction of Turborotalia cerroazulensis, Turborotalia cocoaensis and Turborotalia cunialensis. Quantitative analysis of planktonic foraminiferal assemblages reveals significant changes in the abundance of certain species and the composition of the assemblages. We compare diversity fluctuations to the stable isotope record of Pseudohastigerina naguewichiensis and use multispecies stable isotope analyses to determine the life habitats of the most important species. A major shift in the evenness occurs at ~ 33.8 Ma associated with the extinction of the T cerroazulensis group suggesting acute ecological disturbance. We propose that the extinction of the T. cerroazulensis group at ~ 33.8 Ma was directly related to cooling of sea surface temperatures, while the extinction of Hantkeninidae was due to modifications in the thermal structure of the oceans and associated productivity changes. After the extinctions, renewed origination and diversification occurred, leading to a characteristic Oligocene planktonic foraminifer assemblage.

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: Planktonic foraminifera; Eocene/Oligocene boundary; Extinction; Tanzania; Stable isotopes; Diversity
Publisher: Elsevier
ISSN: 0377-8398
Last Modified: 04 Jun 2017 02:09

Citation Data

Cited 70 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item