Departures from eustasy in Pliocene sea-level records

Proxy data suggest that atmospheric CO 2 levels during the middle of the Pliocene epoch (about 3g€‰Myr ago) were similar to today, leading to the use of this interval as a potential analogue for future climate change. Estimates for mid-Pliocene sea levels range from 10 to 40'm above present, an...

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Main Authors: Raymo, M., Mitrovica, J., O'Leary, Mick, DeConto, R., Hearty, P.
Format: Journal Article
Published: Nature Publishing Group, Macmillan Publishers Ltd 2011
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/12361
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author Raymo, M.
Mitrovica, J.
O'Leary, Mick
DeConto, R.
Hearty, P.
author_facet Raymo, M.
Mitrovica, J.
O'Leary, Mick
DeConto, R.
Hearty, P.
author_sort Raymo, M.
building Curtin Institutional Repository
collection Online Access
description Proxy data suggest that atmospheric CO 2 levels during the middle of the Pliocene epoch (about 3g€‰Myr ago) were similar to today, leading to the use of this interval as a potential analogue for future climate change. Estimates for mid-Pliocene sea levels range from 10 to 40'm above present, and a value of +25'm is often adopted in numerical climate model simulations. A eustatic change of such magnitude implies the complete deglaciation of the West Antarctic and Greenland ice sheets, and significant loss of mass in the East Antarctic ice sheet. However, the effects of glacial isostatic adjustments have not been accounted for in Pliocene sea-level reconstructions. Here we numerically model these effects on Pliocene shoreline features using a gravitationally self-consistent treatment of post-glacial sea-level change. We find that the predicted modern elevation of Pliocene shoreline features can deviate significantly from the eustatic signal, even in the absence of subsequent tectonically-driven movements of the Earth's surface. In our simulations, this non-eustatic sea-level change, at individual locations, is caused primarily by residual isostatic adjustments associated with late Pleistocene glaciation. We conclude that a combination of model results and field observations can help to better constrain sea level in the past, and hence lend insight into the stability of ice sheets under varying climate conditions
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spelling curtin-20.500.11937-123612017-09-13T14:59:51Z Departures from eustasy in Pliocene sea-level records Raymo, M. Mitrovica, J. O'Leary, Mick DeConto, R. Hearty, P. eustacy glaciation climate modeling climate variation proxy climate record shoreline change ice sheet deglaciation carbon dioxide Pliocene paleoclimate reconstruction climate conditions Proxy data suggest that atmospheric CO 2 levels during the middle of the Pliocene epoch (about 3g€‰Myr ago) were similar to today, leading to the use of this interval as a potential analogue for future climate change. Estimates for mid-Pliocene sea levels range from 10 to 40'm above present, and a value of +25'm is often adopted in numerical climate model simulations. A eustatic change of such magnitude implies the complete deglaciation of the West Antarctic and Greenland ice sheets, and significant loss of mass in the East Antarctic ice sheet. However, the effects of glacial isostatic adjustments have not been accounted for in Pliocene sea-level reconstructions. Here we numerically model these effects on Pliocene shoreline features using a gravitationally self-consistent treatment of post-glacial sea-level change. We find that the predicted modern elevation of Pliocene shoreline features can deviate significantly from the eustatic signal, even in the absence of subsequent tectonically-driven movements of the Earth's surface. In our simulations, this non-eustatic sea-level change, at individual locations, is caused primarily by residual isostatic adjustments associated with late Pleistocene glaciation. We conclude that a combination of model results and field observations can help to better constrain sea level in the past, and hence lend insight into the stability of ice sheets under varying climate conditions 2011 Journal Article http://hdl.handle.net/20.500.11937/12361 10.1038/NGEO1118 Nature Publishing Group, Macmillan Publishers Ltd restricted
spellingShingle eustacy
glaciation
climate modeling
climate variation
proxy climate record
shoreline change
ice sheet
deglaciation
carbon dioxide
Pliocene
paleoclimate
reconstruction
climate conditions
Raymo, M.
Mitrovica, J.
O'Leary, Mick
DeConto, R.
Hearty, P.
Departures from eustasy in Pliocene sea-level records
title Departures from eustasy in Pliocene sea-level records
title_full Departures from eustasy in Pliocene sea-level records
title_fullStr Departures from eustasy in Pliocene sea-level records
title_full_unstemmed Departures from eustasy in Pliocene sea-level records
title_short Departures from eustasy in Pliocene sea-level records
title_sort departures from eustasy in pliocene sea-level records
topic eustacy
glaciation
climate modeling
climate variation
proxy climate record
shoreline change
ice sheet
deglaciation
carbon dioxide
Pliocene
paleoclimate
reconstruction
climate conditions
url http://hdl.handle.net/20.500.11937/12361