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Antarctic ice sheet and oceanographic response to eccentricity forcing during the early Miocene

Antarctic ice sheet and oceanographic response to eccentricity forcing during the early Miocene
Antarctic ice sheet and oceanographic response to eccentricity forcing during the early Miocene
Stable isotope records of benthic foraminifera from ODP Site 1264 in the southeastern Atlantic Ocean are presented which resolve the latest Oligocene to early Miocene (~24–19 Ma) climate changes at high temporal resolution (<3 kyr). Using an inverse modelling technique, we decomposed the oxygen isotope record into temperature and ice volume and found that the Antarctic ice sheet expanded episodically during the declining phase of the long-term (~400 kyr) eccentricity cycle and subsequent low short-term (~100 kyr) eccentricity cycle. The largest glaciations are separated by multiple long-term eccentricity cycles, indicating the involvement of a non-linear response mechanism. Our modelling results suggest that during the largest (Mi-1) event, Antarctic ice sheet volume expanded up to its present-day configuration. In addition, we found that distinct ~100 kyr variability occurs during the termination phases of the major Antarctic glaciations, suggesting that climate and ice-sheet response was more susceptible to short-term eccentricity forcing at these times. During two of these termination-phases, ?18O bottom water gradients in the Atlantic ceased to exist, indicating a direct link between global climate, enhanced ice-sheet instability and major oceanographic reorganisations.
1814-9332
869-880
Liebrand, Diederik
bef7cbd7-4fa7-453c-9961-c950a5b87795
Lourens, L.J.
61c02597-1860-45e5-9b78-a1473c7c86dd
Hodell, D.A.
9f55a984-300c-40b9-8f10-ed47d62b46c6
de Boer, B.
e70d5a4d-5b89-49cf-8a09-115bc8732b70
van de Wal, R.S.W.
541169da-bfec-4510-943c-bb114d9d7481
Pälike, H.
b9bf7798-ad8c-479b-8487-dd9a30a61fa5
Liebrand, Diederik
bef7cbd7-4fa7-453c-9961-c950a5b87795
Lourens, L.J.
61c02597-1860-45e5-9b78-a1473c7c86dd
Hodell, D.A.
9f55a984-300c-40b9-8f10-ed47d62b46c6
de Boer, B.
e70d5a4d-5b89-49cf-8a09-115bc8732b70
van de Wal, R.S.W.
541169da-bfec-4510-943c-bb114d9d7481
Pälike, H.
b9bf7798-ad8c-479b-8487-dd9a30a61fa5

Liebrand, Diederik, Lourens, L.J., Hodell, D.A., de Boer, B., van de Wal, R.S.W. and Pälike, H. (2011) Antarctic ice sheet and oceanographic response to eccentricity forcing during the early Miocene. Climate of the Past, 7 (3), 869-880. (doi:10.5194/cp-7-869-2011).

Record type: Article

Abstract

Stable isotope records of benthic foraminifera from ODP Site 1264 in the southeastern Atlantic Ocean are presented which resolve the latest Oligocene to early Miocene (~24–19 Ma) climate changes at high temporal resolution (<3 kyr). Using an inverse modelling technique, we decomposed the oxygen isotope record into temperature and ice volume and found that the Antarctic ice sheet expanded episodically during the declining phase of the long-term (~400 kyr) eccentricity cycle and subsequent low short-term (~100 kyr) eccentricity cycle. The largest glaciations are separated by multiple long-term eccentricity cycles, indicating the involvement of a non-linear response mechanism. Our modelling results suggest that during the largest (Mi-1) event, Antarctic ice sheet volume expanded up to its present-day configuration. In addition, we found that distinct ~100 kyr variability occurs during the termination phases of the major Antarctic glaciations, suggesting that climate and ice-sheet response was more susceptible to short-term eccentricity forcing at these times. During two of these termination-phases, ?18O bottom water gradients in the Atlantic ceased to exist, indicating a direct link between global climate, enhanced ice-sheet instability and major oceanographic reorganisations.

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Published date: 2011
Organisations: Paleooceanography & Palaeoclimate

Identifiers

Local EPrints ID: 201427
URI: http://eprints.soton.ac.uk/id/eprint/201427
ISSN: 1814-9332
PURE UUID: a98a4029-f480-423b-bd40-a3ae6aa13edf

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Date deposited: 27 Oct 2011 13:11
Last modified: 14 Mar 2024 04:22

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Contributors

Author: Diederik Liebrand
Author: L.J. Lourens
Author: D.A. Hodell
Author: B. de Boer
Author: R.S.W. van de Wal
Author: H. Pälike

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