Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica
Recent seismic measurements from upper Thwaites Glacier indicate that the bed-type variability is closely related to the along-flow basal topography. In high-relief subglacial highlands, stoss sides of topographic highs have a relatively higher acoustic impedance (‘hard’ bed) with lower acoustic imp...
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ftdoajarticles:oai:doaj.org/article:cd9a19d11b31406db1c2b6264081c7a0 2023-05-15T13:29:34+02:00 Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica Atsuhiro Muto Richard B. Alley Byron R. Parizek Sridhar Anandakrishnan 2019-12-01T00:00:00Z https://doi.org/10.1017/aog.2019.32 https://doaj.org/article/cd9a19d11b31406db1c2b6264081c7a0 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0260305519000326/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2019.32 0260-3055 1727-5644 https://doaj.org/article/cd9a19d11b31406db1c2b6264081c7a0 Annals of Glaciology, Vol 60, Pp 82-90 (2019) Antarctic glaciology seismic subglacial exploration geophysics subglacial processes subglacial sediments Meteorology. Climatology QC851-999 article 2019 ftdoajarticles https://doi.org/10.1017/aog.2019.32 2023-03-12T01:31:55Z Recent seismic measurements from upper Thwaites Glacier indicate that the bed-type variability is closely related to the along-flow basal topography. In high-relief subglacial highlands, stoss sides of topographic highs have a relatively higher acoustic impedance (‘hard’ bed) with lower acoustic impedance (‘soft’ till) on lee sides. This pattern is similar to observations of many deglaciated terrains. Subglacial hydraulic-potential gradient and its divergence show a tendency for water to diverge over the stoss sides and converge into the lee sides. Convergence favors a thicker or more widespread water system, which can more efficiently decouple ice from the underlying till. Under such circumstances, till deformation does occur but, fluxes are relatively small. Till carried from the lee sides onto stoss sides of downstream bumps should couple to the ice more efficiently, increasing the ability for transport by till deformation. In turn, this suggests that steady-state till transport can be achieved if the stoss-side till layer is thin or discontinuous. In addition, the large basal shear stress generated in the highlands seems too high for a bed lubricated by a continuous although thin deforming till, suggesting till discontinuity, which would allow debris-laden ice to erode bedrock on stoss sides, supplying additional till for transport. Article in Journal/Newspaper Annals of Glaciology Antarc* Antarctic Antarctica Thwaites Glacier West Antarctica Directory of Open Access Journals: DOAJ Articles Antarctic Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) West Antarctica Annals of Glaciology 60 80 82 90 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Antarctic glaciology seismic subglacial exploration geophysics subglacial processes subglacial sediments Meteorology. Climatology QC851-999 |
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Antarctic glaciology seismic subglacial exploration geophysics subglacial processes subglacial sediments Meteorology. Climatology QC851-999 Atsuhiro Muto Richard B. Alley Byron R. Parizek Sridhar Anandakrishnan Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica |
topic_facet |
Antarctic glaciology seismic subglacial exploration geophysics subglacial processes subglacial sediments Meteorology. Climatology QC851-999 |
description |
Recent seismic measurements from upper Thwaites Glacier indicate that the bed-type variability is closely related to the along-flow basal topography. In high-relief subglacial highlands, stoss sides of topographic highs have a relatively higher acoustic impedance (‘hard’ bed) with lower acoustic impedance (‘soft’ till) on lee sides. This pattern is similar to observations of many deglaciated terrains. Subglacial hydraulic-potential gradient and its divergence show a tendency for water to diverge over the stoss sides and converge into the lee sides. Convergence favors a thicker or more widespread water system, which can more efficiently decouple ice from the underlying till. Under such circumstances, till deformation does occur but, fluxes are relatively small. Till carried from the lee sides onto stoss sides of downstream bumps should couple to the ice more efficiently, increasing the ability for transport by till deformation. In turn, this suggests that steady-state till transport can be achieved if the stoss-side till layer is thin or discontinuous. In addition, the large basal shear stress generated in the highlands seems too high for a bed lubricated by a continuous although thin deforming till, suggesting till discontinuity, which would allow debris-laden ice to erode bedrock on stoss sides, supplying additional till for transport. |
format |
Article in Journal/Newspaper |
author |
Atsuhiro Muto Richard B. Alley Byron R. Parizek Sridhar Anandakrishnan |
author_facet |
Atsuhiro Muto Richard B. Alley Byron R. Parizek Sridhar Anandakrishnan |
author_sort |
Atsuhiro Muto |
title |
Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica |
title_short |
Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica |
title_full |
Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica |
title_fullStr |
Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica |
title_full_unstemmed |
Bed-type variability and till (dis)continuity beneath Thwaites Glacier, West Antarctica |
title_sort |
bed-type variability and till (dis)continuity beneath thwaites glacier, west antarctica |
publisher |
Cambridge University Press |
publishDate |
2019 |
url |
https://doi.org/10.1017/aog.2019.32 https://doaj.org/article/cd9a19d11b31406db1c2b6264081c7a0 |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Antarctic Thwaites Glacier West Antarctica |
geographic_facet |
Antarctic Thwaites Glacier West Antarctica |
genre |
Annals of Glaciology Antarc* Antarctic Antarctica Thwaites Glacier West Antarctica |
genre_facet |
Annals of Glaciology Antarc* Antarctic Antarctica Thwaites Glacier West Antarctica |
op_source |
Annals of Glaciology, Vol 60, Pp 82-90 (2019) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0260305519000326/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2019.32 0260-3055 1727-5644 https://doaj.org/article/cd9a19d11b31406db1c2b6264081c7a0 |
op_doi |
https://doi.org/10.1017/aog.2019.32 |
container_title |
Annals of Glaciology |
container_volume |
60 |
container_issue |
80 |
container_start_page |
82 |
op_container_end_page |
90 |
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1766001304531894272 |