The University of Southampton
University of Southampton Institutional Repository

The evolution of pCO2, ice volume and climate during the middle Miocene

Foster, Gavin L., Lear, Caroline H. and Rae, James W.B. (2012) The evolution of pCO2, ice volume and climate during the middle Miocene Earth and Planetary Science Letters, 341-344, pp. 243-254. (doi:10.1016/j.epsl.2012.06.007).

Record type: Article

Abstract

The middle Miocene Climatic Optimum (17–15 Ma; MCO) is a period of global warmth and relatively high CO2 and is thought to be associated with a significant retreat of the Antarctic Ice Sheet (AIS). We present here a new planktic foraminiferal ?11B record from 16.6 to 11.8 Ma from two deep ocean sites currently in equilibrium with the atmosphere with respect to CO2. These new data demonstrate that the evolution of global climate during the middle Miocene (as reflected by changes in the cyrosphere) was well correlated to variations in the concentration of atmospheric CO2. What is more, within our sampling resolution (?1 sample per 300 kyr) there is no evidence of hysteresis in the response of ice volume to CO2 forcing during the middle Miocene, contrary to what is understood about the Antarctic Ice Sheet from ice sheet modelling studies. In agreement with previous data, we show that absolute levels of CO2 during the MCO were relatively modest (350–400 ppm) and levels either side of the MCO are similar or lower than the pre-industrial (200–260 ppm). These new data imply the presence of either a very dynamic AIS at relatively low CO2 during the middle Miocene or the advance and retreat of significant northern hemisphere ice. Recent drilling on the Antarctic margin and shore based studies indicate significant retreat and advance beyond the modern limits of the AIS did occur during the middle Miocene, but the complete loss of the AIS was unlikely. Consequently, it seems that ice volume and climate variations during the middle Miocene probably involved a more dynamic AIS than the modern but also some component of land-based ice in the northern hemisphere.

Full text not available from this repository.

More information

Published date: August 2012
Keywords: boron isotopes, middle Miocene, pCO2, climate change
Organisations: Geochemistry

Identifiers

Local EPrints ID: 342633
URI: http://eprints.soton.ac.uk/id/eprint/342633
ISSN: 0012-821X
PURE UUID: b1484f89-1f92-407d-bff0-810023284909

Catalogue record

Date deposited: 10 Sep 2012 15:58
Last modified: 18 Jul 2017 05:27

Export record

Altmetrics

Contributors

Author: Gavin L. Foster
Author: Caroline H. Lear
Author: James W.B. Rae

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.

×