Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica
Abrupt changes in crystal-orientation fabric (COF), and therefore viscosity, are observednear the base of the ice sheet throughout West Antarctica. We report on active-source seismicobservations from WAIS Divide, mid-stream and downstream on Thwaites Glacier, and the onset regionof Bindschadler Ice...
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ftunivtasecite:oai:ecite.utas.edu.au:103758 2023-05-15T14:03:25+02:00 Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica Horgan, HJ Anandakrishnan, S Alley, RB Burkett, PG Peters, LE 2011 application/pdf https://doi.org/10.3189/002214311797409686 http://ecite.utas.edu.au/103758 en eng Int Glaciol Soc http://ecite.utas.edu.au/103758/1/Horgan_et_al_[2011_JGlac].pdf http://dx.doi.org/10.3189/002214311797409686 Horgan, HJ and Anandakrishnan, S and Alley, RB and Burkett, PG and Peters, LE, Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica, Journal of Glaciology, 57, (204) pp. 639-650. ISSN 0022-1430 (2011) [Refereed Article] http://ecite.utas.edu.au/103758 Earth Sciences Physical Geography and Environmental Geoscience Glaciology Refereed Article PeerReviewed 2011 ftunivtasecite https://doi.org/10.3189/002214311797409686 2019-12-13T22:05:13Z Abrupt changes in crystal-orientation fabric (COF), and therefore viscosity, are observednear the base of the ice sheet throughout West Antarctica. We report on active-source seismicobservations from WAIS Divide, mid-stream and downstream on Thwaites Glacier, and the onset regionof Bindschadler Ice Stream. These data reveal a prevalence of englacial seismic reflectivity in the bottomquarter of the ice sheet. The observed seismic reflectivity is complex but largely bed-conformable,with long-spatial-wavelength features observed in the flow direction and short-wavelength featuresobserved across flow. A correspondence of englacial structures with bed features is also observed. Wedetermine the origin of the reflectivity to be abrupt changes in the COF of ice, based on the following:(1) observations of englacial reflectivity are consistent with current knowledge of COF within ice sheets,(2) englacial reflectivity caused by COF contrasts requires the simplest genesis, especially at ice divides,and (3) amplitude analysis shows that the observed englacial reflectivity can be explained by contrastsin seismic velocity due to COF changes. We note that the downstream increase in the quantity andcomplexity of observations indicates that direct observations of COF at ice divides likely underestimatethe role that fabric plays in ice-sheet dynamics. Article in Journal/Newspaper Antarc* Antarctica Antarctica Journal Bindschadler Ice Stream Ice Sheet Journal of Glaciology Thwaites Glacier West Antarctica eCite UTAS (University of Tasmania) Bindschadler Ice Stream ENVELOPE(-142.000,-142.000,-81.000,-81.000) Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) West Antarctica Journal of Glaciology 57 204 639 650 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology |
spellingShingle |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology Horgan, HJ Anandakrishnan, S Alley, RB Burkett, PG Peters, LE Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica |
topic_facet |
Earth Sciences Physical Geography and Environmental Geoscience Glaciology |
description |
Abrupt changes in crystal-orientation fabric (COF), and therefore viscosity, are observednear the base of the ice sheet throughout West Antarctica. We report on active-source seismicobservations from WAIS Divide, mid-stream and downstream on Thwaites Glacier, and the onset regionof Bindschadler Ice Stream. These data reveal a prevalence of englacial seismic reflectivity in the bottomquarter of the ice sheet. The observed seismic reflectivity is complex but largely bed-conformable,with long-spatial-wavelength features observed in the flow direction and short-wavelength featuresobserved across flow. A correspondence of englacial structures with bed features is also observed. Wedetermine the origin of the reflectivity to be abrupt changes in the COF of ice, based on the following:(1) observations of englacial reflectivity are consistent with current knowledge of COF within ice sheets,(2) englacial reflectivity caused by COF contrasts requires the simplest genesis, especially at ice divides,and (3) amplitude analysis shows that the observed englacial reflectivity can be explained by contrastsin seismic velocity due to COF changes. We note that the downstream increase in the quantity andcomplexity of observations indicates that direct observations of COF at ice divides likely underestimatethe role that fabric plays in ice-sheet dynamics. |
format |
Article in Journal/Newspaper |
author |
Horgan, HJ Anandakrishnan, S Alley, RB Burkett, PG Peters, LE |
author_facet |
Horgan, HJ Anandakrishnan, S Alley, RB Burkett, PG Peters, LE |
author_sort |
Horgan, HJ |
title |
Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica |
title_short |
Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica |
title_full |
Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica |
title_fullStr |
Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica |
title_full_unstemmed |
Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica |
title_sort |
englacial seismic reflectivity: imaging crystal-orientation fabric in west antarctica |
publisher |
Int Glaciol Soc |
publishDate |
2011 |
url |
https://doi.org/10.3189/002214311797409686 http://ecite.utas.edu.au/103758 |
long_lat |
ENVELOPE(-142.000,-142.000,-81.000,-81.000) ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Bindschadler Ice Stream Thwaites Glacier West Antarctica |
geographic_facet |
Bindschadler Ice Stream Thwaites Glacier West Antarctica |
genre |
Antarc* Antarctica Antarctica Journal Bindschadler Ice Stream Ice Sheet Journal of Glaciology Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctica Antarctica Journal Bindschadler Ice Stream Ice Sheet Journal of Glaciology Thwaites Glacier West Antarctica |
op_relation |
http://ecite.utas.edu.au/103758/1/Horgan_et_al_[2011_JGlac].pdf http://dx.doi.org/10.3189/002214311797409686 Horgan, HJ and Anandakrishnan, S and Alley, RB and Burkett, PG and Peters, LE, Englacial seismic reflectivity: imaging crystal-orientation fabric in West Antarctica, Journal of Glaciology, 57, (204) pp. 639-650. ISSN 0022-1430 (2011) [Refereed Article] http://ecite.utas.edu.au/103758 |
op_doi |
https://doi.org/10.3189/002214311797409686 |
container_title |
Journal of Glaciology |
container_volume |
57 |
container_issue |
204 |
container_start_page |
639 |
op_container_end_page |
650 |
_version_ |
1766274071069196288 |