Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica
The grounding line of the Siple Coast incorporates six major ice streams, which together drain around a third of the West Antarctic Ice Sheet. Previously, the ~2000 km-long feature had only been sampled and directly observed at Whillans Ice Stream. This thesis examines glaciomarine sediment and proc...
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ftvictoriauwfig:oai:figshare.com:article/16906837 2023-05-15T13:35:14+02:00 Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica Calkin, Theo 2021-10-30T00:00:00Z https://doi.org/10.26686/wgtn.16906837.v1 https://figshare.com/articles/thesis/Sedimentology_of_the_grounding_zone_of_the_Kamb_Ice_Stream_Siple_Coast_West_Antarctica/16906837 unknown doi:10.26686/wgtn.16906837.v1 https://figshare.com/articles/thesis/Sedimentology_of_the_grounding_zone_of_the_Kamb_Ice_Stream_Siple_Coast_West_Antarctica/16906837 Author Retains Copyright Sedimentology grounding line grounding zone Siple Coast structure from motion rainout melt out hot water drill sedimentary facies diamicton School: School of Geography Environment and Earth Sciences Unit: Antarctic Research Centre 040310 Sedimentology 960399 Climate and Climate Change not elsewhere classified Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science Text Thesis 2021 ftvictoriauwfig https://doi.org/10.26686/wgtn.16906837.v1 2021-11-25T00:02:45Z The grounding line of the Siple Coast incorporates six major ice streams, which together drain around a third of the West Antarctic Ice Sheet. Previously, the ~2000 km-long feature had only been sampled and directly observed at Whillans Ice Stream. This thesis examines glaciomarine sediment and processes operating at the presently stagnant Kamb Ice Stream (KIS) grounding zone ~3.3 km seaward of the modern grounding line (Lat. -82.78, Long. -155.16), where the ice is 590 m thick and overlies a 30 m thick water column. KIS-GZ is the planned site for a deep drilling project in 2023. The sea floor was accessed using a hot water drill in the 2019/20 Antarctic field season. A remotely operated submersible (‘Icefin’) was deployed under the ice shelf, which provided 800 m of sea floor video toward the grounding line. A small number of short (~0.6 m) gravity cores were collected from the seafloor, one of which was examined in this study. The Icefin video imagery was processed using Structure-from-Motion (SfM) software, enabling the identification of two previously unrecognised sea floor sedimentary facies. One is defined by ubiquitous cm-scale ripples in fine-medium sand, where the ripples are aligned with the prevailing tidal currents flowing parallel to the grounding line. Observed current speeds are too low for the ripples to be generated under the modern oceanographic regime. The second facies is defined by abundant dropstones in mediumcoarse sand. A transition zone separates the two facies. Previously unidentified decimetre-scale bedforms are present in the transition zone and near the borehole. The lithological, geochemical, and microfossil properties of the gravity core were analysed. The core sediment is sandy diamicton with weak stratification defined by decimetre-scale changes in clast abundance. Mineral counts, zircon ages, Nd/Sr isotopes, and an immature composition indicate this sediment is sourced within the Kamb catchment. The core also contains reworked late Oligocene-late Miocene diatoms. Quaternary ... Thesis Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Kamb Ice Stream West Antarctica Whillans Ice Stream Open Access Victoria University of Wellington / Te Herenga Waka Antarctic Kamb Ice Stream ENVELOPE(-145.000,-145.000,-82.250,-82.250) Siple ENVELOPE(-83.917,-83.917,-75.917,-75.917) Siple Coast ENVELOPE(-155.000,-155.000,-82.000,-82.000) West Antarctic Ice Sheet West Antarctica Whillans ENVELOPE(-64.250,-64.250,-84.450,-84.450) Whillans Ice Stream ENVELOPE(-145.000,-145.000,-83.667,-83.667) |
institution |
Open Polar |
collection |
Open Access Victoria University of Wellington / Te Herenga Waka |
op_collection_id |
ftvictoriauwfig |
language |
unknown |
topic |
Sedimentology grounding line grounding zone Siple Coast structure from motion rainout melt out hot water drill sedimentary facies diamicton School: School of Geography Environment and Earth Sciences Unit: Antarctic Research Centre 040310 Sedimentology 960399 Climate and Climate Change not elsewhere classified Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science |
spellingShingle |
Sedimentology grounding line grounding zone Siple Coast structure from motion rainout melt out hot water drill sedimentary facies diamicton School: School of Geography Environment and Earth Sciences Unit: Antarctic Research Centre 040310 Sedimentology 960399 Climate and Climate Change not elsewhere classified Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science Calkin, Theo Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica |
topic_facet |
Sedimentology grounding line grounding zone Siple Coast structure from motion rainout melt out hot water drill sedimentary facies diamicton School: School of Geography Environment and Earth Sciences Unit: Antarctic Research Centre 040310 Sedimentology 960399 Climate and Climate Change not elsewhere classified Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science |
description |
The grounding line of the Siple Coast incorporates six major ice streams, which together drain around a third of the West Antarctic Ice Sheet. Previously, the ~2000 km-long feature had only been sampled and directly observed at Whillans Ice Stream. This thesis examines glaciomarine sediment and processes operating at the presently stagnant Kamb Ice Stream (KIS) grounding zone ~3.3 km seaward of the modern grounding line (Lat. -82.78, Long. -155.16), where the ice is 590 m thick and overlies a 30 m thick water column. KIS-GZ is the planned site for a deep drilling project in 2023. The sea floor was accessed using a hot water drill in the 2019/20 Antarctic field season. A remotely operated submersible (‘Icefin’) was deployed under the ice shelf, which provided 800 m of sea floor video toward the grounding line. A small number of short (~0.6 m) gravity cores were collected from the seafloor, one of which was examined in this study. The Icefin video imagery was processed using Structure-from-Motion (SfM) software, enabling the identification of two previously unrecognised sea floor sedimentary facies. One is defined by ubiquitous cm-scale ripples in fine-medium sand, where the ripples are aligned with the prevailing tidal currents flowing parallel to the grounding line. Observed current speeds are too low for the ripples to be generated under the modern oceanographic regime. The second facies is defined by abundant dropstones in mediumcoarse sand. A transition zone separates the two facies. Previously unidentified decimetre-scale bedforms are present in the transition zone and near the borehole. The lithological, geochemical, and microfossil properties of the gravity core were analysed. The core sediment is sandy diamicton with weak stratification defined by decimetre-scale changes in clast abundance. Mineral counts, zircon ages, Nd/Sr isotopes, and an immature composition indicate this sediment is sourced within the Kamb catchment. The core also contains reworked late Oligocene-late Miocene diatoms. Quaternary ... |
format |
Thesis |
author |
Calkin, Theo |
author_facet |
Calkin, Theo |
author_sort |
Calkin, Theo |
title |
Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica |
title_short |
Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica |
title_full |
Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica |
title_fullStr |
Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica |
title_full_unstemmed |
Sedimentology of the grounding zone of the Kamb Ice Stream, Siple Coast, West Antarctica |
title_sort |
sedimentology of the grounding zone of the kamb ice stream, siple coast, west antarctica |
publishDate |
2021 |
url |
https://doi.org/10.26686/wgtn.16906837.v1 https://figshare.com/articles/thesis/Sedimentology_of_the_grounding_zone_of_the_Kamb_Ice_Stream_Siple_Coast_West_Antarctica/16906837 |
long_lat |
ENVELOPE(-145.000,-145.000,-82.250,-82.250) ENVELOPE(-83.917,-83.917,-75.917,-75.917) ENVELOPE(-155.000,-155.000,-82.000,-82.000) ENVELOPE(-64.250,-64.250,-84.450,-84.450) ENVELOPE(-145.000,-145.000,-83.667,-83.667) |
geographic |
Antarctic Kamb Ice Stream Siple Siple Coast West Antarctic Ice Sheet West Antarctica Whillans Whillans Ice Stream |
geographic_facet |
Antarctic Kamb Ice Stream Siple Siple Coast West Antarctic Ice Sheet West Antarctica Whillans Whillans Ice Stream |
genre |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Kamb Ice Stream West Antarctica Whillans Ice Stream |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Kamb Ice Stream West Antarctica Whillans Ice Stream |
op_relation |
doi:10.26686/wgtn.16906837.v1 https://figshare.com/articles/thesis/Sedimentology_of_the_grounding_zone_of_the_Kamb_Ice_Stream_Siple_Coast_West_Antarctica/16906837 |
op_rights |
Author Retains Copyright |
op_doi |
https://doi.org/10.26686/wgtn.16906837.v1 |
_version_ |
1766063272703819776 |