Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica
An up to 180 m-thick debris avalanche deposit related to Ferrar large igneous province magmatism is observed at central Allan Hills, Antarctica. This Jurassic debris avalanche deposit forms the lower part (member m₁) of the Mawson Formation and is overlain by thick volcaniclastic layers containing a...
Published in: | Geological Society of America Bulletin |
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Online Access: | https://espace.inrs.ca/id/eprint/1897/ https://espace.inrs.ca/id/eprint/1897/1/Reubi-et-al%28central-AH%292005-web%5B1%5D.pdf https://doi.org/10.1130/B25766.1 |
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ftinrsquebec:oai:espace.inrs.ca:1897 2023-05-15T13:52:40+02:00 Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica Reubi, Olivier Ross, Pierre-Simon White, James D. L. 2005 application/pdf https://espace.inrs.ca/id/eprint/1897/ https://espace.inrs.ca/id/eprint/1897/1/Reubi-et-al%28central-AH%292005-web%5B1%5D.pdf https://doi.org/10.1130/B25766.1 en eng https://espace.inrs.ca/id/eprint/1897/1/Reubi-et-al%28central-AH%292005-web%5B1%5D.pdf Reubi, Olivier, Ross, Pierre-Simon et White, James D. L. (2005). Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica Geological Society of America Bulletin , vol. 117 , nº 11-12. p. 1615-1628. DOI:10.1130/B25766.1 <https://doi.org/10.1130/B25766.1>. doi:10.1130/B25766.1 avalanche débris volcanisme formation de Mawson Central Allan Hills Antarctique Article Évalué par les pairs 2005 ftinrsquebec https://doi.org/10.1130/B25766.1 2023-02-10T11:41:35Z An up to 180 m-thick debris avalanche deposit related to Ferrar large igneous province magmatism is observed at central Allan Hills, Antarctica. This Jurassic debris avalanche deposit forms the lower part (member m₁) of the Mawson Formation and is overlain by thick volcaniclastic layers containing a mixture of basaltic and sedimentary debris (member m₂). The m1 deposit consists of a chaotic assemblage of breccia panels and megablocks up to 80 m across. In contrast to m₂, it is composed essentially of sedimentary material derived from the underlying Beacon Supergroup. The observed structures and textures suggest that the breccias in m1 were mostly produced by progressive fragmentation of megablocks during transport but also to a lesser extent by disruption and ingestion of the substrate by the moving debris avalanche. The upper surface of the debris avalanche deposit lacks large hummocks, and sandstone breccias dominate volumetrically over megablocks within the deposits. This indicates pervasive and relatively uniform fragmentation of the moving mass, and probably reflects the weak and relatively homogenous nature of the material involved. The avalanche flowed into a pre-existing topographic depression carved into the Beacon sequence, and flow indicators reveal a northeastward movement. The source area is probably now hidden under the Antarctic ice sheet. Sparse basaltic bodies, which were hot and plastic during transport in m₁, reveal the role of Ferrar magmatism in triggering the avalanche, possibly in relation to the emplacement of large sub-surface intrusions. The documented deposits indicate that debris avalanches are among the various phenomena that can accompany the early stages of large igneous province magmatism, despite the common absence of large central volcanic edifices. Where large igneous provinces develop in association with faulting, or slow pre-eruptive uplift accompanied by deep valley incision, there is a high probability that feeder dikes will approach the surface in areas of steep ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Antarctique* Ice Sheet Institut national de la recherche scientifique, Québec: Espace INRS Antarctic The Antarctic Allan Hills ENVELOPE(159.667,159.667,-76.717,-76.717) Geological Society of America Bulletin 117 11 1615 |
institution |
Open Polar |
collection |
Institut national de la recherche scientifique, Québec: Espace INRS |
op_collection_id |
ftinrsquebec |
language |
English |
topic |
avalanche débris volcanisme formation de Mawson Central Allan Hills Antarctique |
spellingShingle |
avalanche débris volcanisme formation de Mawson Central Allan Hills Antarctique Reubi, Olivier Ross, Pierre-Simon White, James D. L. Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica |
topic_facet |
avalanche débris volcanisme formation de Mawson Central Allan Hills Antarctique |
description |
An up to 180 m-thick debris avalanche deposit related to Ferrar large igneous province magmatism is observed at central Allan Hills, Antarctica. This Jurassic debris avalanche deposit forms the lower part (member m₁) of the Mawson Formation and is overlain by thick volcaniclastic layers containing a mixture of basaltic and sedimentary debris (member m₂). The m1 deposit consists of a chaotic assemblage of breccia panels and megablocks up to 80 m across. In contrast to m₂, it is composed essentially of sedimentary material derived from the underlying Beacon Supergroup. The observed structures and textures suggest that the breccias in m1 were mostly produced by progressive fragmentation of megablocks during transport but also to a lesser extent by disruption and ingestion of the substrate by the moving debris avalanche. The upper surface of the debris avalanche deposit lacks large hummocks, and sandstone breccias dominate volumetrically over megablocks within the deposits. This indicates pervasive and relatively uniform fragmentation of the moving mass, and probably reflects the weak and relatively homogenous nature of the material involved. The avalanche flowed into a pre-existing topographic depression carved into the Beacon sequence, and flow indicators reveal a northeastward movement. The source area is probably now hidden under the Antarctic ice sheet. Sparse basaltic bodies, which were hot and plastic during transport in m₁, reveal the role of Ferrar magmatism in triggering the avalanche, possibly in relation to the emplacement of large sub-surface intrusions. The documented deposits indicate that debris avalanches are among the various phenomena that can accompany the early stages of large igneous province magmatism, despite the common absence of large central volcanic edifices. Where large igneous provinces develop in association with faulting, or slow pre-eruptive uplift accompanied by deep valley incision, there is a high probability that feeder dikes will approach the surface in areas of steep ... |
format |
Article in Journal/Newspaper |
author |
Reubi, Olivier Ross, Pierre-Simon White, James D. L. |
author_facet |
Reubi, Olivier Ross, Pierre-Simon White, James D. L. |
author_sort |
Reubi, Olivier |
title |
Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica |
title_short |
Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica |
title_full |
Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica |
title_fullStr |
Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica |
title_full_unstemmed |
Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica |
title_sort |
debris avalanche deposits associated with large igneous province volcanism: an example from the mawson formation, central allan hills, antarctica |
publishDate |
2005 |
url |
https://espace.inrs.ca/id/eprint/1897/ https://espace.inrs.ca/id/eprint/1897/1/Reubi-et-al%28central-AH%292005-web%5B1%5D.pdf https://doi.org/10.1130/B25766.1 |
long_lat |
ENVELOPE(159.667,159.667,-76.717,-76.717) |
geographic |
Antarctic The Antarctic Allan Hills |
geographic_facet |
Antarctic The Antarctic Allan Hills |
genre |
Antarc* Antarctic Antarctica Antarctique* Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Antarctique* Ice Sheet |
op_relation |
https://espace.inrs.ca/id/eprint/1897/1/Reubi-et-al%28central-AH%292005-web%5B1%5D.pdf Reubi, Olivier, Ross, Pierre-Simon et White, James D. L. (2005). Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica Geological Society of America Bulletin , vol. 117 , nº 11-12. p. 1615-1628. DOI:10.1130/B25766.1 <https://doi.org/10.1130/B25766.1>. doi:10.1130/B25766.1 |
op_doi |
https://doi.org/10.1130/B25766.1 |
container_title |
Geological Society of America Bulletin |
container_volume |
117 |
container_issue |
11 |
container_start_page |
1615 |
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1766257094075351040 |