The amplitude and origin of sea-level variability during the Pliocene epoch
Earth is heading towards a climate that last existed more than three million years ago (Ma) during the 'mid-Pliocene warm period'(1), when atmospheric carbon dioxide concentrations were about 400 parts per million, global sea level oscillated in response to orbital forcing(2,3) and peak gl...
Published in: | Nature |
---|---|
Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
NATURE PUBLISHING GROUP
2021
|
Subjects: | |
Online Access: | http://repositoriodigital.uct.cl/handle/10925/4059 https://doi.org/10.1038/s41586-019-1619-z |
id |
ftunivctemuco:oai:repositoriodigital.uct.cl:10925/4059 |
---|---|
record_format |
openpolar |
spelling |
ftunivctemuco:oai:repositoriodigital.uct.cl:10925/4059 2023-05-15T13:58:13+02:00 The amplitude and origin of sea-level variability during the Pliocene epoch Grant, G. R. Naish, T. R. Dunbar, G. B. Stocchi, P. Kominz, M. A. Kamp, P. J. J. Tapia Orellana, Claudio McKay, R. M. Levy, R. H. Patterson, M. O. 2021-04-30T17:06:08Z http://repositoriodigital.uct.cl/handle/10925/4059 https://doi.org/10.1038/s41586-019-1619-z en eng NATURE PUBLISHING GROUP NATURE,Vol.574,237-+,2019 http://repositoriodigital.uct.cl/handle/10925/4059 doi:10.1038/s41586-019-1619-z NATURE Article 2021 ftunivctemuco https://doi.org/10.1038/s41586-019-1619-z 2021-05-01T23:50:55Z Earth is heading towards a climate that last existed more than three million years ago (Ma) during the 'mid-Pliocene warm period'(1), when atmospheric carbon dioxide concentrations were about 400 parts per million, global sea level oscillated in response to orbital forcing(2,3) and peak global-mean sea level (GMSL) may have reached about 20 metres above the present-day value(4,5). For sea-level rise of this magnitude, extensive retreat or collapse of the Greenland, West Antarctic and marine-based sectors of the East Antarctic ice sheets is required. Yet the relative amplitude of sea-level variations within glacial-interglacial cycles remains poorly constrained. To address this, we calibrate a theoretical relationship between modern sediment transport by waves and water depth, and then apply the technique to grain size in a continuous 800-metre-thick Pliocene sequence of shallow-marine sediments from Whanganui Basin, New Zealand. Water-depth variations obtained in this way, after corrections for tectonic subsidence, yield cyclic relative sea-level (RSL) variations. Here we show that sea level varied on average by 13 +/- 5 metres over glacial-interglacial cycles during the middle-to-late Pliocene (about 3.3-2.5 Ma). The resulting record is independent of the global ice volume proxy(3) (as derived from the deep-ocean oxygen isotope record) and sea-level cycles are in phase with 20-thousand-year (kyr) periodic changes in insolation over Antarctica, paced by eccentricity-modulated orbital precession(6) between 3.3 and 2.7 Ma. Thereafter, sea-level fluctuations are paced by the 41-kyr period of cycles in Earth's axial tilt as ice sheets stabilize on Antarctica and intensify in the Northern Hemisphere(3,6). Strictly, we provide the amplitude of RSL change, rather than absolute GMSL change. However, simulations of RSL change based on glacio-isostatic adjustment show that our record approximates eustatic sea level, defined here as GMSL unregistered to the centre of the Earth. Nonetheless, under conservative assumptions, our estimates limit maximum Pliocene sea-level rise to less than 25 metres and provide new constraints on polar ice-volume variability under the climate conditions predicted for this century. Article in Journal/Newspaper Antarc* Antarctic Antarctica Greenland Repositorio Académico de la Universidad Católica de Temuco (UCT) Antarctic Greenland New Zealand Nature 574 7777 237 241 |
institution |
Open Polar |
collection |
Repositorio Académico de la Universidad Católica de Temuco (UCT) |
op_collection_id |
ftunivctemuco |
language |
English |
description |
Earth is heading towards a climate that last existed more than three million years ago (Ma) during the 'mid-Pliocene warm period'(1), when atmospheric carbon dioxide concentrations were about 400 parts per million, global sea level oscillated in response to orbital forcing(2,3) and peak global-mean sea level (GMSL) may have reached about 20 metres above the present-day value(4,5). For sea-level rise of this magnitude, extensive retreat or collapse of the Greenland, West Antarctic and marine-based sectors of the East Antarctic ice sheets is required. Yet the relative amplitude of sea-level variations within glacial-interglacial cycles remains poorly constrained. To address this, we calibrate a theoretical relationship between modern sediment transport by waves and water depth, and then apply the technique to grain size in a continuous 800-metre-thick Pliocene sequence of shallow-marine sediments from Whanganui Basin, New Zealand. Water-depth variations obtained in this way, after corrections for tectonic subsidence, yield cyclic relative sea-level (RSL) variations. Here we show that sea level varied on average by 13 +/- 5 metres over glacial-interglacial cycles during the middle-to-late Pliocene (about 3.3-2.5 Ma). The resulting record is independent of the global ice volume proxy(3) (as derived from the deep-ocean oxygen isotope record) and sea-level cycles are in phase with 20-thousand-year (kyr) periodic changes in insolation over Antarctica, paced by eccentricity-modulated orbital precession(6) between 3.3 and 2.7 Ma. Thereafter, sea-level fluctuations are paced by the 41-kyr period of cycles in Earth's axial tilt as ice sheets stabilize on Antarctica and intensify in the Northern Hemisphere(3,6). Strictly, we provide the amplitude of RSL change, rather than absolute GMSL change. However, simulations of RSL change based on glacio-isostatic adjustment show that our record approximates eustatic sea level, defined here as GMSL unregistered to the centre of the Earth. Nonetheless, under conservative assumptions, our estimates limit maximum Pliocene sea-level rise to less than 25 metres and provide new constraints on polar ice-volume variability under the climate conditions predicted for this century. |
format |
Article in Journal/Newspaper |
author |
Grant, G. R. Naish, T. R. Dunbar, G. B. Stocchi, P. Kominz, M. A. Kamp, P. J. J. Tapia Orellana, Claudio McKay, R. M. Levy, R. H. Patterson, M. O. |
spellingShingle |
Grant, G. R. Naish, T. R. Dunbar, G. B. Stocchi, P. Kominz, M. A. Kamp, P. J. J. Tapia Orellana, Claudio McKay, R. M. Levy, R. H. Patterson, M. O. The amplitude and origin of sea-level variability during the Pliocene epoch |
author_facet |
Grant, G. R. Naish, T. R. Dunbar, G. B. Stocchi, P. Kominz, M. A. Kamp, P. J. J. Tapia Orellana, Claudio McKay, R. M. Levy, R. H. Patterson, M. O. |
author_sort |
Grant, G. R. |
title |
The amplitude and origin of sea-level variability during the Pliocene epoch |
title_short |
The amplitude and origin of sea-level variability during the Pliocene epoch |
title_full |
The amplitude and origin of sea-level variability during the Pliocene epoch |
title_fullStr |
The amplitude and origin of sea-level variability during the Pliocene epoch |
title_full_unstemmed |
The amplitude and origin of sea-level variability during the Pliocene epoch |
title_sort |
amplitude and origin of sea-level variability during the pliocene epoch |
publisher |
NATURE PUBLISHING GROUP |
publishDate |
2021 |
url |
http://repositoriodigital.uct.cl/handle/10925/4059 https://doi.org/10.1038/s41586-019-1619-z |
geographic |
Antarctic Greenland New Zealand |
geographic_facet |
Antarctic Greenland New Zealand |
genre |
Antarc* Antarctic Antarctica Greenland |
genre_facet |
Antarc* Antarctic Antarctica Greenland |
op_source |
NATURE |
op_relation |
NATURE,Vol.574,237-+,2019 http://repositoriodigital.uct.cl/handle/10925/4059 doi:10.1038/s41586-019-1619-z |
op_doi |
https://doi.org/10.1038/s41586-019-1619-z |
container_title |
Nature |
container_volume |
574 |
container_issue |
7777 |
container_start_page |
237 |
op_container_end_page |
241 |
_version_ |
1766266384609705984 |