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Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus
It has recently been suggested that deformed crustal plateaus on Venus may be composed of felsic (silica-rich) rocks, possibly supporting the idea of an ancient ocean there. However, these plateaus have a tendency to collapse owing to flow of the viscous lower crust. Felsic minerals, especially wate...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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National Academy of Sciences
2023
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9934203/ https://www.ncbi.nlm.nih.gov/pubmed/36623181 http://dx.doi.org/10.1073/pnas.2216311120 |
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author | Nimmo, Francis Mackwell, Stephen |
author_facet | Nimmo, Francis Mackwell, Stephen |
author_sort | Nimmo, Francis |
collection | PubMed |
description | It has recently been suggested that deformed crustal plateaus on Venus may be composed of felsic (silica-rich) rocks, possibly supporting the idea of an ancient ocean there. However, these plateaus have a tendency to collapse owing to flow of the viscous lower crust. Felsic minerals, especially water-bearing ones, are much weaker and thus lead to more rapid collapse, than more mafic minerals. We model plateau topographic evolution using a non-Newtonian viscous relaxation code. Despite uncertainties in the likely crustal thickness and surface heat flux, we find that quartz-dominated rheologies relax too rapidly to be plausible plateau-forming material. For plateaus dominated by a dry anorthite rheology, survival is possible only if the background crustal thickness is less than 29 km, unless the heat flux on Venus is less than the radiogenic lower bound of 34 [Formula: see text]. Future spacecraft determinations of plateau crustal thickness and mineralogy will place firmer constraints on Venus’s heat flux. |
format | Online Article Text |
id | pubmed-9934203 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | National Academy of Sciences |
record_format | MEDLINE/PubMed |
spelling | pubmed-99342032023-07-09 Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus Nimmo, Francis Mackwell, Stephen Proc Natl Acad Sci U S A Physical Sciences It has recently been suggested that deformed crustal plateaus on Venus may be composed of felsic (silica-rich) rocks, possibly supporting the idea of an ancient ocean there. However, these plateaus have a tendency to collapse owing to flow of the viscous lower crust. Felsic minerals, especially water-bearing ones, are much weaker and thus lead to more rapid collapse, than more mafic minerals. We model plateau topographic evolution using a non-Newtonian viscous relaxation code. Despite uncertainties in the likely crustal thickness and surface heat flux, we find that quartz-dominated rheologies relax too rapidly to be plausible plateau-forming material. For plateaus dominated by a dry anorthite rheology, survival is possible only if the background crustal thickness is less than 29 km, unless the heat flux on Venus is less than the radiogenic lower bound of 34 [Formula: see text]. Future spacecraft determinations of plateau crustal thickness and mineralogy will place firmer constraints on Venus’s heat flux. National Academy of Sciences 2023-01-09 2023-01-17 /pmc/articles/PMC9934203/ /pubmed/36623181 http://dx.doi.org/10.1073/pnas.2216311120 Text en Copyright © 2023 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) . |
spellingShingle | Physical Sciences Nimmo, Francis Mackwell, Stephen Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus |
title | Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus |
title_full | Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus |
title_fullStr | Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus |
title_full_unstemmed | Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus |
title_short | Viscous relaxation as a probe of heat flux and crustal plateau composition on Venus |
title_sort | viscous relaxation as a probe of heat flux and crustal plateau composition on venus |
topic | Physical Sciences |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9934203/ https://www.ncbi.nlm.nih.gov/pubmed/36623181 http://dx.doi.org/10.1073/pnas.2216311120 |
work_keys_str_mv | AT nimmofrancis viscousrelaxationasaprobeofheatfluxandcrustalplateaucompositiononvenus AT mackwellstephen viscousrelaxationasaprobeofheatfluxandcrustalplateaucompositiononvenus |