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Durham University

Department of Geography

Departmental Research Projects

Reconstructing Intermediate Water Temperature Response to Pliocene - Pleistocene Climates

A research project of the Department of Geography.

Background

This NERC-funded research investigates changes to the ocean-climate system from the warm mid-Pliocene to present day (~4 million years ago to the present) in the southwest Pacific Ocean (Figure A). This time period is particularly interesting as it encompasses large climatic transitions of the Pliocene-Pleistocene boundary (~2.6 million years ago), the mid-Pleistocene Transition (~1.2 million years ago), and glacial-interglacial scale climatic variability (encompassing both 100,000- and 41,000- year cyclicity). Additionally, this research aims to examine causes for the unexplained benthic foraminifera Stilostomella Extinction across the mid-Pleistocene Transition.

Specifically, we aim to answer the following three key questions:

(i) did intermediate waters cool from the Pliocene to the Pleistocene?
(ii) did cooling in intermediate waters drive benthic foraminiferal extinctions?
(iii) did surface-ocean cooling in the Southern Ocean drive cooling in the intermediate waters?

To answer these questions, our research will focus on reconstructing 3 distinct aspects of the ocean-climate system using deep sea sediments from DSDP site 593 (Figure B):

(i) use the Mg/Ca ratio of the benthic foraminifera, Uvigerina spp. (Figure C) to estimate past intermediate water temperature;
(ii) characterise changes in benthic foraminiferal species assemblages to identify extinction events;
(iii) use the alkenone UK37' index to examine sea surface temperature changes.


Figure A: The location of our sediment core, DSDP 593 on the Western Flank of the Challenger Plateau.

Figure B: Sampling of a section of sediment core DSDP 593 at the KCC Core facility in Kochi, Japan
(Photograph by A. Elmore).
Figure C: Image of a microscopic foraminifera Uvigerina peregrina that will be used for Mg/Ca analyses (image from http://forambarcoding.unige.ch).

External Collaborators

  • Professor Harry Elderfield (Cambridge University, Collaborator)
  • Dr Sev Kender (British Geologic Survey, Collaborator)

Staff

From the Department of Geography

From other departments