Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica
Mount Achernar moraine is a terrestrial sediment archive that preserves a record of ice-sheet dynamics and climate over multiple glacial cycles. Similar records exist in other blue ice moraines elsewhere on the continent, but an understanding of how these moraines form is limited. We propose a model...
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ftdoajarticles:oai:doaj.org/article:7ff050a6b0044c6d9cdb86c88d7216f9 2023-05-15T14:01:53+02:00 Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica Christine M. Kassab Kathy J. Licht Rickard Petersson Katrin Lindbäck Joseph A. Graly Michael R. Kaplan 2020-02-01T00:00:00Z https://doi.org/10.1017/jog.2019.83 https://doaj.org/article/7ff050a6b0044c6d9cdb86c88d7216f9 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0022143019000832/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2019.83 0022-1430 1727-5652 https://doaj.org/article/7ff050a6b0044c6d9cdb86c88d7216f9 Journal of Glaciology, Vol 66, Pp 49-60 (2020) Blue ice ground-penetrating radar moraine formation Environmental sciences GE1-350 Meteorology. Climatology QC851-999 article 2020 ftdoajarticles https://doi.org/10.1017/jog.2019.83 2023-03-12T01:30:57Z Mount Achernar moraine is a terrestrial sediment archive that preserves a record of ice-sheet dynamics and climate over multiple glacial cycles. Similar records exist in other blue ice moraines elsewhere on the continent, but an understanding of how these moraines form is limited. We propose a model to explain the formation of extensive, coherent blue ice moraine sequences based on the integration of ground-penetrating radar (GPR) data with ice velocity and surface exposure ages. GPR transects (100 and 25 MHz) both perpendicular and parallel to moraine ridges at Mount Achernar reveal an internal structure defined by alternating relatively clean ice and steeply dipping debris bands extending to depth, and where visible, to the underlying bedrock surface. Sediment is carried to the surface from depth along these debris bands, and sublimates out of the ice, accumulating over time (>300 ka). The internal pattern of dipping reflectors, combined with increasing surface exposure ages, suggest sequential exposure of the sediment where ice and debris accretes laterally to form the moraine. Subsurface structure varies across the moraine and can be linked to changes in basal entrainment conditions. We speculate that higher concentrations of debris may have been entrained in the ice during colder glacial periods or entrained more proximal to the moraine sequence. Article in Journal/Newspaper Antarc* Antarctica Ice Sheet Journal of Glaciology Directory of Open Access Journals: DOAJ Articles Transantarctic Mountains Achernar ENVELOPE(160.933,160.933,-84.200,-84.200) Mount Achernar ENVELOPE(160.933,160.933,-84.200,-84.200) Journal of Glaciology 66 255 49 60 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Blue ice ground-penetrating radar moraine formation Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
spellingShingle |
Blue ice ground-penetrating radar moraine formation Environmental sciences GE1-350 Meteorology. Climatology QC851-999 Christine M. Kassab Kathy J. Licht Rickard Petersson Katrin Lindbäck Joseph A. Graly Michael R. Kaplan Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica |
topic_facet |
Blue ice ground-penetrating radar moraine formation Environmental sciences GE1-350 Meteorology. Climatology QC851-999 |
description |
Mount Achernar moraine is a terrestrial sediment archive that preserves a record of ice-sheet dynamics and climate over multiple glacial cycles. Similar records exist in other blue ice moraines elsewhere on the continent, but an understanding of how these moraines form is limited. We propose a model to explain the formation of extensive, coherent blue ice moraine sequences based on the integration of ground-penetrating radar (GPR) data with ice velocity and surface exposure ages. GPR transects (100 and 25 MHz) both perpendicular and parallel to moraine ridges at Mount Achernar reveal an internal structure defined by alternating relatively clean ice and steeply dipping debris bands extending to depth, and where visible, to the underlying bedrock surface. Sediment is carried to the surface from depth along these debris bands, and sublimates out of the ice, accumulating over time (>300 ka). The internal pattern of dipping reflectors, combined with increasing surface exposure ages, suggest sequential exposure of the sediment where ice and debris accretes laterally to form the moraine. Subsurface structure varies across the moraine and can be linked to changes in basal entrainment conditions. We speculate that higher concentrations of debris may have been entrained in the ice during colder glacial periods or entrained more proximal to the moraine sequence. |
format |
Article in Journal/Newspaper |
author |
Christine M. Kassab Kathy J. Licht Rickard Petersson Katrin Lindbäck Joseph A. Graly Michael R. Kaplan |
author_facet |
Christine M. Kassab Kathy J. Licht Rickard Petersson Katrin Lindbäck Joseph A. Graly Michael R. Kaplan |
author_sort |
Christine M. Kassab |
title |
Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica |
title_short |
Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica |
title_full |
Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica |
title_fullStr |
Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica |
title_full_unstemmed |
Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica |
title_sort |
formation and evolution of an extensive blue ice moraine in central transantarctic mountains, antarctica |
publisher |
Cambridge University Press |
publishDate |
2020 |
url |
https://doi.org/10.1017/jog.2019.83 https://doaj.org/article/7ff050a6b0044c6d9cdb86c88d7216f9 |
long_lat |
ENVELOPE(160.933,160.933,-84.200,-84.200) ENVELOPE(160.933,160.933,-84.200,-84.200) |
geographic |
Transantarctic Mountains Achernar Mount Achernar |
geographic_facet |
Transantarctic Mountains Achernar Mount Achernar |
genre |
Antarc* Antarctica Ice Sheet Journal of Glaciology |
genre_facet |
Antarc* Antarctica Ice Sheet Journal of Glaciology |
op_source |
Journal of Glaciology, Vol 66, Pp 49-60 (2020) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0022143019000832/type/journal_article https://doaj.org/toc/0022-1430 https://doaj.org/toc/1727-5652 doi:10.1017/jog.2019.83 0022-1430 1727-5652 https://doaj.org/article/7ff050a6b0044c6d9cdb86c88d7216f9 |
op_doi |
https://doi.org/10.1017/jog.2019.83 |
container_title |
Journal of Glaciology |
container_volume |
66 |
container_issue |
255 |
container_start_page |
49 |
op_container_end_page |
60 |
_version_ |
1766271933750444032 |