Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars
When the Hale impact crater penetrated the martian cryosphere 1Ga, landforms indicating post-impact volatile mobilisation were generated. We have found landforms in the ejecta blanket of Hale Crater similar to ‘permafrost molards’ found in periglacial environments on Earth, and probably related to t...
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2023
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ftunivpadovairis:oai:www.research.unipd.it:11577/3481411 2024-02-27T08:41:13+00:00 Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars Morino C. Conway S. Philippe M. Peignaux C. Svennevig K. Lucas A. Noblet A. Roberti G. Butcher F. Collins-May J. Morino, C. Conway, S. Philippe, M. Peignaux, C. Svennevig, K. Lucas, A. Noblet, A. Roberti, G. Butcher, F. Collins-May, J. 2023 https://hdl.handle.net/11577/3481411 https://doi.org/10.1016/j.icarus.2022.115363 eng eng Academic Press Inc. info:eu-repo/semantics/altIdentifier/wos/WOS:000895776200007 volume:391 firstpage:115363 journal:ICARUS https://hdl.handle.net/11577/3481411 doi:10.1016/j.icarus.2022.115363 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85142534150 info:eu-repo/semantics/openAccess Ejecta flow Ground-ice Molard Permafrost Volatiles info:eu-repo/semantics/article 2023 ftunivpadovairis https://doi.org/10.1016/j.icarus.2022.115363 2024-01-31T17:32:42Z When the Hale impact crater penetrated the martian cryosphere 1Ga, landforms indicating post-impact volatile mobilisation were generated. We have found landforms in the ejecta blanket of Hale Crater similar to ‘permafrost molards’ found in periglacial environments on Earth, and probably related to the past or present presence of volatiles at/near the surface. Permafrost molards are conical mounds of debris associated with landslide deposits, resulting from the degradation of blocks of ice-rich material mobilised by a landslide in periglacial terrains. Here we analyse the spatial and topographic distribution of conical mounds around the Hale crater at regional and local scales, and compare them to those of molards on the deposits of the Mount Meager debris avalanche in Canada. Hale Crater's conical mounds are located at the distal boundary of the thickest ejecta blanket, which is the closest to the main crater. We observe a similar spatial arrangement of molards along the distal parts of the terminal lobe of the Mount Meager debris avalanche. We then compare the morphology and morphometrics of the conical mounds on Hale Crater to those of terrestrial molards on the Paatuut and Niiortuut rock avalanches in western Greenland. We find that morphology and setting of conical mounds within Hale Crater ejecta are consistent with the formation pathway of molards on Earth. We infer that they originated from blocks of ice-cemented regolith that were produced by the Hale-crater-forming impact, transported by the ejecta flows, and finally degraded to cones of debris (molards) on loss of the interstitial ice. The similarities in distribution between the ejecta flows of Hale and Mount Meager debris avalanche on Earth suggest that the mounds resulted from the rheological separation of the ejecta flows, with a relatively fluid-poor phase that allowed the volatile-rich blocks to survive transport. This supports the prevailing hypothesis that the Hale impact event penetrated the martian cryosphere, providing important constraints ... Article in Journal/Newspaper Greenland Ice permafrost Padua Research Archive (IRIS - Università degli Studi di Padova) Canada Greenland Hale ENVELOPE(-86.317,-86.317,-78.067,-78.067) Main Crater ENVELOPE(167.167,167.167,-77.533,-77.533) Paatuut ENVELOPE(-52.750,-52.750,70.250,70.250) Icarus 391 115363 |
institution |
Open Polar |
collection |
Padua Research Archive (IRIS - Università degli Studi di Padova) |
op_collection_id |
ftunivpadovairis |
language |
English |
topic |
Ejecta flow Ground-ice Molard Permafrost Volatiles |
spellingShingle |
Ejecta flow Ground-ice Molard Permafrost Volatiles Morino C. Conway S. Philippe M. Peignaux C. Svennevig K. Lucas A. Noblet A. Roberti G. Butcher F. Collins-May J. Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars |
topic_facet |
Ejecta flow Ground-ice Molard Permafrost Volatiles |
description |
When the Hale impact crater penetrated the martian cryosphere 1Ga, landforms indicating post-impact volatile mobilisation were generated. We have found landforms in the ejecta blanket of Hale Crater similar to ‘permafrost molards’ found in periglacial environments on Earth, and probably related to the past or present presence of volatiles at/near the surface. Permafrost molards are conical mounds of debris associated with landslide deposits, resulting from the degradation of blocks of ice-rich material mobilised by a landslide in periglacial terrains. Here we analyse the spatial and topographic distribution of conical mounds around the Hale crater at regional and local scales, and compare them to those of molards on the deposits of the Mount Meager debris avalanche in Canada. Hale Crater's conical mounds are located at the distal boundary of the thickest ejecta blanket, which is the closest to the main crater. We observe a similar spatial arrangement of molards along the distal parts of the terminal lobe of the Mount Meager debris avalanche. We then compare the morphology and morphometrics of the conical mounds on Hale Crater to those of terrestrial molards on the Paatuut and Niiortuut rock avalanches in western Greenland. We find that morphology and setting of conical mounds within Hale Crater ejecta are consistent with the formation pathway of molards on Earth. We infer that they originated from blocks of ice-cemented regolith that were produced by the Hale-crater-forming impact, transported by the ejecta flows, and finally degraded to cones of debris (molards) on loss of the interstitial ice. The similarities in distribution between the ejecta flows of Hale and Mount Meager debris avalanche on Earth suggest that the mounds resulted from the rheological separation of the ejecta flows, with a relatively fluid-poor phase that allowed the volatile-rich blocks to survive transport. This supports the prevailing hypothesis that the Hale impact event penetrated the martian cryosphere, providing important constraints ... |
author2 |
Morino, C. Conway, S. Philippe, M. Peignaux, C. Svennevig, K. Lucas, A. Noblet, A. Roberti, G. Butcher, F. Collins-May, J. |
format |
Article in Journal/Newspaper |
author |
Morino C. Conway S. Philippe M. Peignaux C. Svennevig K. Lucas A. Noblet A. Roberti G. Butcher F. Collins-May J. |
author_facet |
Morino C. Conway S. Philippe M. Peignaux C. Svennevig K. Lucas A. Noblet A. Roberti G. Butcher F. Collins-May J. |
author_sort |
Morino C. |
title |
Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars |
title_short |
Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars |
title_full |
Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars |
title_fullStr |
Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars |
title_full_unstemmed |
Permafrost molards as an analogue for ejecta-ice interactions at Hale Crater, Mars |
title_sort |
permafrost molards as an analogue for ejecta-ice interactions at hale crater, mars |
publisher |
Academic Press Inc. |
publishDate |
2023 |
url |
https://hdl.handle.net/11577/3481411 https://doi.org/10.1016/j.icarus.2022.115363 |
long_lat |
ENVELOPE(-86.317,-86.317,-78.067,-78.067) ENVELOPE(167.167,167.167,-77.533,-77.533) ENVELOPE(-52.750,-52.750,70.250,70.250) |
geographic |
Canada Greenland Hale Main Crater Paatuut |
geographic_facet |
Canada Greenland Hale Main Crater Paatuut |
genre |
Greenland Ice permafrost |
genre_facet |
Greenland Ice permafrost |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000895776200007 volume:391 firstpage:115363 journal:ICARUS https://hdl.handle.net/11577/3481411 doi:10.1016/j.icarus.2022.115363 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85142534150 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.icarus.2022.115363 |
container_title |
Icarus |
container_volume |
391 |
container_start_page |
115363 |
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