The University of Southampton
University of Southampton Institutional Repository

Equatorial Pacific "stable isotope reference curve" for the Oligocene (abstract of paper presented at AGU Fall Meeting, San Francisco, 5-9 Dec 2005)

Record type: Article

We present an uninterrupted chronology of climate and ocean carbon chemistry from ODP Site 1218 recovered in the equatorial Pacific, from the Eocene / Oligocene to the Oligocene / Miocene boundary, ~34 to 23 Ma. Using astronomically age calibrated data we find a strong imprint of the 405, 127 and 96-thousand-year (kyr) Earth's eccentricity as well as a dominant influence of the 1.2 million year (Myr) obliquity amplitude modulation cycles on periodically re-occurring Oligocene glacial and carbon cycle events. In combination, these astronomical modulations act as the ``heartbeat'' of the Oligocene climate system. The response of the climate system to intricate orbital variations is striking and suggests a fundamental role of the carbon cycle in the interaction between solar forcing and climate. Our record provides a new high-resolution view of the Oligocene climate system, prompts a re-evaluation of the previously hypothesised late Oligocene deglaciation, and sheds new light on Oligocene inter-ocean isotope gradients. Salient observations include foraminiferal benthic stable oxygen and carbon isotopes that co-vary, a phase lag of ?13C w.r.t. ?18O for the 405 kyr cycle, preferential filtering of longer orbital periods in ?13C, presumably due to ?CO2 reservoir buffering. We then use simple orbitally forced carbon cycle box models and manage to re-create the patterns observed in our data, including the overall strong amplitude of 405 kyr cycles in ?13C. Depending on ice-sheet presence and pCO2 concentrations, our model predicts re-occurring conditions favouring glaciations every 2.4 Myr, including the Eocene/Oligocene transition.

HTML AGU2005_abstract.html - Other
Download (5kB)

Citation

Pälike, H., Norris, R.D., Herrle, J.O., Wilson, P.A., Lear, C.H., Coxall, H.K. and Tripati, A.K. (2005) Equatorial Pacific "stable isotope reference curve" for the Oligocene (abstract of paper presented at AGU Fall Meeting, San Francisco, 5-9 Dec 2005) EOS: Transactions American Geophysical Union, 86, (52, Supplement), p.F1334.

More information

Published date: 2005

Identifiers

Local EPrints ID: 41924
URI: http://eprints.soton.ac.uk/id/eprint/41924
ISSN: 0096-3941
PURE UUID: 594170d2-1749-41ec-be29-be9ebc453ae5

Catalogue record

Date deposited: 18 Oct 2006
Last modified: 17 Jul 2017 15:25

Export record

Contributors

Author: H. Pälike
Author: R.D. Norris
Author: J.O. Herrle
Author: P.A. Wilson
Author: C.H. Lear
Author: H.K. Coxall
Author: A.K. Tripati

University divisions


Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×