A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window
Abstract Paleoshorelines serve as measures of ancient sea level and ice volume but are affected by solid Earth deformation including processes such as glacial isostatic adjustment (GIA) and mantle dynamic topography (DT). The early Pliocene Epoch is an important target for sea‐level reconstructions...
Published in: | Geochemistry, Geophysics, Geosystems |
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ftdoajarticles:oai:doaj.org/article:a71e5d55ed3642d8af7addc8250143c9 2023-12-03T10:24:27+01:00 A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window Andrew Hollyday Jacqueline Austermann Andrew Lloyd Mark Hoggard Fred Richards Alessio Rovere 2023-02-01T00:00:00Z https://doi.org/10.1029/2022GC010648 https://doaj.org/article/a71e5d55ed3642d8af7addc8250143c9 EN eng Wiley https://doi.org/10.1029/2022GC010648 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2022GC010648 https://doaj.org/article/a71e5d55ed3642d8af7addc8250143c9 Geochemistry, Geophysics, Geosystems, Vol 24, Iss 2, Pp n/a-n/a (2023) geodynamics sea‐level change Pliocene glacial isostatic adjustment mantle convection Patagonia Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.1029/2022GC010648 2023-11-05T01:35:59Z Abstract Paleoshorelines serve as measures of ancient sea level and ice volume but are affected by solid Earth deformation including processes such as glacial isostatic adjustment (GIA) and mantle dynamic topography (DT). The early Pliocene Epoch is an important target for sea‐level reconstructions as it contains information about the stability of ice sheets during a climate warmer than today. Along the southeastern passive margin of Argentina, three paleoshorelines date to early Pliocene times (4.8–5.5 Ma), and their variable present‐day elevations (36–180 m) reflect a unique topographic deformation signature. We use a mantle convection model to back‐advect present‐day buoyancy variations, including those that correspond to the Patagonian slab window. Varying the viscosity and initial tomography‐derived mantle buoyancy structures allows us to compute a suite of predictions of DT change that, when compared to GIA‐corrected shoreline elevations, makes it possible to identify both the most likely convection parameters and the most likely DT change. Our simulations illuminate an interplay of upwelling asthenosphere through the Patagonian slab window and coincident downwelling of the subducted Nazca slab in the mantle transition zone. This flow leads to differential upwarping of the southern Patagonian foreland since early Pliocene times, in line with the observations. Using our most likely DT change leads to an estimate of global mean sea level of 17.5 ± 6.4 m (1σ) in the early Pliocene Epoch. This confirms that sea level was significantly higher than present and can be used to calibrate ice sheet models. Article in Journal/Newspaper Ice Sheet Directory of Open Access Journals: DOAJ Articles Argentina Patagonia Geochemistry, Geophysics, Geosystems 24 2 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
geodynamics sea‐level change Pliocene glacial isostatic adjustment mantle convection Patagonia Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
spellingShingle |
geodynamics sea‐level change Pliocene glacial isostatic adjustment mantle convection Patagonia Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 Andrew Hollyday Jacqueline Austermann Andrew Lloyd Mark Hoggard Fred Richards Alessio Rovere A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window |
topic_facet |
geodynamics sea‐level change Pliocene glacial isostatic adjustment mantle convection Patagonia Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
description |
Abstract Paleoshorelines serve as measures of ancient sea level and ice volume but are affected by solid Earth deformation including processes such as glacial isostatic adjustment (GIA) and mantle dynamic topography (DT). The early Pliocene Epoch is an important target for sea‐level reconstructions as it contains information about the stability of ice sheets during a climate warmer than today. Along the southeastern passive margin of Argentina, three paleoshorelines date to early Pliocene times (4.8–5.5 Ma), and their variable present‐day elevations (36–180 m) reflect a unique topographic deformation signature. We use a mantle convection model to back‐advect present‐day buoyancy variations, including those that correspond to the Patagonian slab window. Varying the viscosity and initial tomography‐derived mantle buoyancy structures allows us to compute a suite of predictions of DT change that, when compared to GIA‐corrected shoreline elevations, makes it possible to identify both the most likely convection parameters and the most likely DT change. Our simulations illuminate an interplay of upwelling asthenosphere through the Patagonian slab window and coincident downwelling of the subducted Nazca slab in the mantle transition zone. This flow leads to differential upwarping of the southern Patagonian foreland since early Pliocene times, in line with the observations. Using our most likely DT change leads to an estimate of global mean sea level of 17.5 ± 6.4 m (1σ) in the early Pliocene Epoch. This confirms that sea level was significantly higher than present and can be used to calibrate ice sheet models. |
format |
Article in Journal/Newspaper |
author |
Andrew Hollyday Jacqueline Austermann Andrew Lloyd Mark Hoggard Fred Richards Alessio Rovere |
author_facet |
Andrew Hollyday Jacqueline Austermann Andrew Lloyd Mark Hoggard Fred Richards Alessio Rovere |
author_sort |
Andrew Hollyday |
title |
A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window |
title_short |
A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window |
title_full |
A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window |
title_fullStr |
A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window |
title_full_unstemmed |
A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window |
title_sort |
revised estimate of early pliocene global mean sea level using geodynamic models of the patagonian slab window |
publisher |
Wiley |
publishDate |
2023 |
url |
https://doi.org/10.1029/2022GC010648 https://doaj.org/article/a71e5d55ed3642d8af7addc8250143c9 |
geographic |
Argentina Patagonia |
geographic_facet |
Argentina Patagonia |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Geochemistry, Geophysics, Geosystems, Vol 24, Iss 2, Pp n/a-n/a (2023) |
op_relation |
https://doi.org/10.1029/2022GC010648 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2022GC010648 https://doaj.org/article/a71e5d55ed3642d8af7addc8250143c9 |
op_doi |
https://doi.org/10.1029/2022GC010648 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
24 |
container_issue |
2 |
_version_ |
1784272869576933376 |