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Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance

The three large volcanoes in the Tharsis region of Mars: Arsia, Pavonis, and Ascraeus Montes all have fan-shaped deposits (FSDs) on their northern or western flanks consisting of a combination of parallel ridges, knobby/hummocky terrain, and a smooth, viscous flow-like unit. The FSDs are hypothesize...

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Autores principales: Parsons, Reid A., Kanzaki, Tomohiro, Hemmi, Ryodo, Miyamoto, Hideaki
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7194259/
https://www.ncbi.nlm.nih.gov/pubmed/32382472
http://dx.doi.org/10.1186/s40645-020-0323-9
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author Parsons, Reid A.
Kanzaki, Tomohiro
Hemmi, Ryodo
Miyamoto, Hideaki
author_facet Parsons, Reid A.
Kanzaki, Tomohiro
Hemmi, Ryodo
Miyamoto, Hideaki
author_sort Parsons, Reid A.
collection PubMed
description The three large volcanoes in the Tharsis region of Mars: Arsia, Pavonis, and Ascraeus Montes all have fan-shaped deposits (FSDs) on their northern or western flanks consisting of a combination of parallel ridges, knobby/hummocky terrain, and a smooth, viscous flow-like unit. The FSDs are hypothesized to have formed in the Amazonian during a period of high spin-axis obliquity which redistributed polar ice to the equatorial Tharsis region resulting in thick (> 2 km), flowing ice deposits. Based on previous ice flow simulations and crater surveys, the ridges are interpreted to be recessional drop moraines formed as debris on the ice sheet surface was transported to the ice margin—forming a long ridge sequence over an extended (∼100 Myr) period of ice sheet retreat. We test this hypothesis using a high-resolution, thermomechanical ice sheet model assuming a lower ice loss rate (~ 0.5 mm/year) than prior work based on new experimental results of ice sublimation below a protective debris layer. Our ice flow simulation results, when combined with topographic observations from a long sequence of ridges located interior of the Pavonis FSD, show that the ridged units were more likely deposited during one or more periods of glacial advance (instead of retreat) when repetitive pulses (approx. 120 kyr periodicity) of ice accumulation during high obliquity produced kinematic waves which advected a large volume of surface debris to the ice margin. If ridge deposition does occur during glacial advance, it could explain the cyclic pattern of ridge spacing and would link the dominant, 120 kyr periodicity in obliquity to the time interval between adjacent ridges. By measuring the spacing between these ridges and applying this timescale, we constrain the velocity of glacial margin to be between 0.2 and 4 cm/Earth year—in close agreement with the numerical simulation. This re-interpretation of the FSD ridged unit suggests that the timescale of FSD formation (and perhaps the duration of the Amazonian high obliquity period) was shorter than previously reported. [Image: see text]
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spelling pubmed-71942592020-05-05 Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance Parsons, Reid A. Kanzaki, Tomohiro Hemmi, Ryodo Miyamoto, Hideaki Prog Earth Planet Sci Research Article The three large volcanoes in the Tharsis region of Mars: Arsia, Pavonis, and Ascraeus Montes all have fan-shaped deposits (FSDs) on their northern or western flanks consisting of a combination of parallel ridges, knobby/hummocky terrain, and a smooth, viscous flow-like unit. The FSDs are hypothesized to have formed in the Amazonian during a period of high spin-axis obliquity which redistributed polar ice to the equatorial Tharsis region resulting in thick (> 2 km), flowing ice deposits. Based on previous ice flow simulations and crater surveys, the ridges are interpreted to be recessional drop moraines formed as debris on the ice sheet surface was transported to the ice margin—forming a long ridge sequence over an extended (∼100 Myr) period of ice sheet retreat. We test this hypothesis using a high-resolution, thermomechanical ice sheet model assuming a lower ice loss rate (~ 0.5 mm/year) than prior work based on new experimental results of ice sublimation below a protective debris layer. Our ice flow simulation results, when combined with topographic observations from a long sequence of ridges located interior of the Pavonis FSD, show that the ridged units were more likely deposited during one or more periods of glacial advance (instead of retreat) when repetitive pulses (approx. 120 kyr periodicity) of ice accumulation during high obliquity produced kinematic waves which advected a large volume of surface debris to the ice margin. If ridge deposition does occur during glacial advance, it could explain the cyclic pattern of ridge spacing and would link the dominant, 120 kyr periodicity in obliquity to the time interval between adjacent ridges. By measuring the spacing between these ridges and applying this timescale, we constrain the velocity of glacial margin to be between 0.2 and 4 cm/Earth year—in close agreement with the numerical simulation. This re-interpretation of the FSD ridged unit suggests that the timescale of FSD formation (and perhaps the duration of the Amazonian high obliquity period) was shorter than previously reported. [Image: see text] Springer Berlin Heidelberg 2020-03-12 2020 /pmc/articles/PMC7194259/ /pubmed/32382472 http://dx.doi.org/10.1186/s40645-020-0323-9 Text en © The Author(s). 2020 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Research Article
Parsons, Reid A.
Kanzaki, Tomohiro
Hemmi, Ryodo
Miyamoto, Hideaki
Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance
title Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance
title_full Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance
title_fullStr Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance
title_full_unstemmed Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance
title_short Cold-based glaciation of Pavonis Mons, Mars: evidence for moraine deposition during glacial advance
title_sort cold-based glaciation of pavonis mons, mars: evidence for moraine deposition during glacial advance
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7194259/
https://www.ncbi.nlm.nih.gov/pubmed/32382472
http://dx.doi.org/10.1186/s40645-020-0323-9
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