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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Uppsala universitet, Luft-, vatten- och landskapslära
2020
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ftuppsalauniv:oai:DiVA.org:uu-406598 2023-05-15T14:00:26+02:00 Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica Kassab, Christine M. Licht, Kathy J. Pettersson, Rickard Lindback, Katrin Graly, Joseph A. Kaplan, Michael R. 2020 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-406598 https://doi.org/10.1017/jog.2019.83 eng eng Uppsala universitet, Luft-, vatten- och landskapslära Indiana Univ Purdue Univ, Dept Earth Sci, 723 W Michigan St,SL118, Indianapolis, IN 46202 USA Norwegian Polar Res Inst, Fram Ctr, POB 6606, NO-9296 Tromso, Norway Indiana Univ Purdue Univ, Dept Earth Sci, 723 W Michigan St,SL118, Indianapolis, IN 46202 USA;Northumbria Univ, Dept Geog & Environm Sci, Ellison Pl, Newcastle Upon Tyne NE1 8ST, Tyne & Wear, England Lamont Doherty Earth Observ, Div Geochem, Palisades, NY 10964 USA CAMBRIDGE UNIV PRESS Journal of Glaciology, 0022-1430, 2020, 66:255, s. 49-60 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-406598 doi:10.1017/jog.2019.83 ISI:000509742700005 info:eu-repo/semantics/openAccess Blue ice ground-penetrating radar moraine formation Physical Geography Naturgeografi Article in journal info:eu-repo/semantics/article text 2020 ftuppsalauniv https://doi.org/10.1017/jog.2019.83 2023-02-23T21:52:13Z 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 Uppsala University: Publications (DiVA) Achernar ENVELOPE(160.933,160.933,-84.200,-84.200) Mount Achernar ENVELOPE(160.933,160.933,-84.200,-84.200) Transantarctic Mountains Journal of Glaciology 66 255 49 60 |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Blue ice ground-penetrating radar moraine formation Physical Geography Naturgeografi |
spellingShingle |
Blue ice ground-penetrating radar moraine formation Physical Geography Naturgeografi Kassab, Christine M. Licht, Kathy J. Pettersson, Rickard Lindback, Katrin Graly, Joseph A. Kaplan, Michael R. Formation and evolution of an extensive blue ice moraine in central Transantarctic Mountains, Antarctica |
topic_facet |
Blue ice ground-penetrating radar moraine formation Physical Geography Naturgeografi |
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 |
Kassab, Christine M. Licht, Kathy J. Pettersson, Rickard Lindback, Katrin Graly, Joseph A. Kaplan, Michael R. |
author_facet |
Kassab, Christine M. Licht, Kathy J. Pettersson, Rickard Lindback, Katrin Graly, Joseph A. Kaplan, Michael R. |
author_sort |
Kassab, Christine M. |
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 |
Uppsala universitet, Luft-, vatten- och landskapslära |
publishDate |
2020 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-406598 https://doi.org/10.1017/jog.2019.83 |
long_lat |
ENVELOPE(160.933,160.933,-84.200,-84.200) ENVELOPE(160.933,160.933,-84.200,-84.200) |
geographic |
Achernar Mount Achernar Transantarctic Mountains |
geographic_facet |
Achernar Mount Achernar Transantarctic Mountains |
genre |
Antarc* Antarctica Ice Sheet Journal of Glaciology |
genre_facet |
Antarc* Antarctica Ice Sheet Journal of Glaciology |
op_relation |
Journal of Glaciology, 0022-1430, 2020, 66:255, s. 49-60 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-406598 doi:10.1017/jog.2019.83 ISI:000509742700005 |
op_rights |
info:eu-repo/semantics/openAccess |
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_ |
1766269527756111872 |