Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica
Large volumes of aeolian sand and dust are deflated from unconsolidated till deposits, and supraglacial debris surrounding McMurdo Sound, Antarctica. This material is transported offshore with windblown snow onto extensive winter-formed sea ice in the southwest Ross Sea, and is subsequently released...
Main Author: | |
---|---|
Format: | Thesis |
Language: | unknown |
Published: |
2013
|
Subjects: | |
Online Access: | https://doi.org/10.26686/wgtn.17005975.v1 |
id |
ftsmithonian:oai:figshare.com:article/17005975 |
---|---|
record_format |
openpolar |
spelling |
ftsmithonian:oai:figshare.com:article/17005975 2023-05-15T13:37:42+02:00 Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica Chewings, Jane Margaret (11694577) 2013-01-01T00:00:00Z https://doi.org/10.26686/wgtn.17005975.v1 unknown https://figshare.com/articles/thesis/Sedimentology_and_numerical_modelling_of_aeolian_sediment_dispersal_McMurdo_Sound_southwest_Ross_Sea_Antarctica/17005975 doi:10.26686/wgtn.17005975.v1 Author Retains Copyright Sedimentology Aeolian Sedimentation Antarctica School: Antarctic Research Centre Unit: School of Geography Environment and Earth Sciences 040310 Sedimentology 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science Text Thesis 2013 ftsmithonian https://doi.org/10.26686/wgtn.17005975.v1 2021-12-19T21:55:21Z Large volumes of aeolian sand and dust are deflated from unconsolidated till deposits, and supraglacial debris surrounding McMurdo Sound, Antarctica. This material is transported offshore with windblown snow onto extensive winter-formed sea ice in the southwest Ross Sea, and is subsequently released into the water-column during summer sea ice breakup. Aeolian sediment samples were collected from a ~600 km² area of sea ice in western McMurdo Sound to determine the magnitude of deposition and identify sediment sources. A new 2-dimensional numerical aeolian sediment transport model (NaMASTE) tuned specifically for the McMurdo Sound area, was used to explore the ability of the local wind system to move sediment from source areas to sea ice and to determine the pattern and extent of aeolian sediment dispersal to the southwest Ross Sea. Debris deposits on the McMurdo Ice Shelf debris bands are the most dominant sediment source for the area. Unconsolidated deposits between Cape Bernacchi and Spike Cape, and the Taylor Valley mouth are significant secondary deposits. Mass accumulation rates varied between 0.15 g m⁻² y⁻¹ and 54.6 g m⁻² y⁻¹, equating to a background aeolian sediment accumulation rate, excluding extremely high values, of 1.14 ± 0.59 g m⁻² y⁻¹ for the McMurdo Sound coastal sea ice zone. This is 3–5 orders of magnitude more than global background dust fallout for the Ross Sea. Modal grain size is very-fine sand to coarse silt. Notably, much of this material is distributed in localised, high sand content plumes that are oriented downwind from source, with finer deposits found outside these zones. An average seafloor linear sedimentation rate of 0.2 cm ky⁻¹ is calculated for McMurdo Sound, which is minor compared to biogenic sedimentation for the region. This equates to ~0.7 Gg y⁻¹ aeolian sediment entering McMurdo Sound during sea ice melt. Application of NaMASTE successfully simulated the general aeolian sediment distribution pattern. Testing of model variables suggests that aeolian material is mainly transported during strong (>20 m s⁻¹) wind events. Modelling also suggests aeolian material from McMurdo Sound can be transported north to the Drygalski Ice Tongue, ~250 km from source, but only in very trace quantities. Thesis Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf McMurdo Sound Ross Sea Sea ice Unknown Antarctic Ross Sea McMurdo Sound Taylor Valley ENVELOPE(163.000,163.000,-77.617,-77.617) McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) Drygalski ENVELOPE(-61.000,-61.000,-64.717,-64.717) Drygalski Ice Tongue ENVELOPE(163.500,163.500,-75.400,-75.400) Bernacchi ENVELOPE(163.850,163.850,-77.483,-77.483) Cape Bernacchi ENVELOPE(163.450,163.450,-77.467,-77.467) Spike Cape ENVELOPE(163.567,163.567,-77.300,-77.300) |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
ftsmithonian |
language |
unknown |
topic |
Sedimentology Aeolian Sedimentation Antarctica School: Antarctic Research Centre Unit: School of Geography Environment and Earth Sciences 040310 Sedimentology 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science |
spellingShingle |
Sedimentology Aeolian Sedimentation Antarctica School: Antarctic Research Centre Unit: School of Geography Environment and Earth Sciences 040310 Sedimentology 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science Chewings, Jane Margaret (11694577) Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica |
topic_facet |
Sedimentology Aeolian Sedimentation Antarctica School: Antarctic Research Centre Unit: School of Geography Environment and Earth Sciences 040310 Sedimentology 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geology Degree Level: Masters Degree Name: Master of Science |
description |
Large volumes of aeolian sand and dust are deflated from unconsolidated till deposits, and supraglacial debris surrounding McMurdo Sound, Antarctica. This material is transported offshore with windblown snow onto extensive winter-formed sea ice in the southwest Ross Sea, and is subsequently released into the water-column during summer sea ice breakup. Aeolian sediment samples were collected from a ~600 km² area of sea ice in western McMurdo Sound to determine the magnitude of deposition and identify sediment sources. A new 2-dimensional numerical aeolian sediment transport model (NaMASTE) tuned specifically for the McMurdo Sound area, was used to explore the ability of the local wind system to move sediment from source areas to sea ice and to determine the pattern and extent of aeolian sediment dispersal to the southwest Ross Sea. Debris deposits on the McMurdo Ice Shelf debris bands are the most dominant sediment source for the area. Unconsolidated deposits between Cape Bernacchi and Spike Cape, and the Taylor Valley mouth are significant secondary deposits. Mass accumulation rates varied between 0.15 g m⁻² y⁻¹ and 54.6 g m⁻² y⁻¹, equating to a background aeolian sediment accumulation rate, excluding extremely high values, of 1.14 ± 0.59 g m⁻² y⁻¹ for the McMurdo Sound coastal sea ice zone. This is 3–5 orders of magnitude more than global background dust fallout for the Ross Sea. Modal grain size is very-fine sand to coarse silt. Notably, much of this material is distributed in localised, high sand content plumes that are oriented downwind from source, with finer deposits found outside these zones. An average seafloor linear sedimentation rate of 0.2 cm ky⁻¹ is calculated for McMurdo Sound, which is minor compared to biogenic sedimentation for the region. This equates to ~0.7 Gg y⁻¹ aeolian sediment entering McMurdo Sound during sea ice melt. Application of NaMASTE successfully simulated the general aeolian sediment distribution pattern. Testing of model variables suggests that aeolian material is mainly transported during strong (>20 m s⁻¹) wind events. Modelling also suggests aeolian material from McMurdo Sound can be transported north to the Drygalski Ice Tongue, ~250 km from source, but only in very trace quantities. |
format |
Thesis |
author |
Chewings, Jane Margaret (11694577) |
author_facet |
Chewings, Jane Margaret (11694577) |
author_sort |
Chewings, Jane Margaret (11694577) |
title |
Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica |
title_short |
Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica |
title_full |
Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica |
title_fullStr |
Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica |
title_full_unstemmed |
Sedimentology and numerical modelling of aeolian sediment dispersal, McMurdo Sound, southwest Ross Sea, Antarctica |
title_sort |
sedimentology and numerical modelling of aeolian sediment dispersal, mcmurdo sound, southwest ross sea, antarctica |
publishDate |
2013 |
url |
https://doi.org/10.26686/wgtn.17005975.v1 |
long_lat |
ENVELOPE(163.000,163.000,-77.617,-77.617) ENVELOPE(166.500,166.500,-78.000,-78.000) ENVELOPE(-61.000,-61.000,-64.717,-64.717) ENVELOPE(163.500,163.500,-75.400,-75.400) ENVELOPE(163.850,163.850,-77.483,-77.483) ENVELOPE(163.450,163.450,-77.467,-77.467) ENVELOPE(163.567,163.567,-77.300,-77.300) |
geographic |
Antarctic Ross Sea McMurdo Sound Taylor Valley McMurdo Ice Shelf Drygalski Drygalski Ice Tongue Bernacchi Cape Bernacchi Spike Cape |
geographic_facet |
Antarctic Ross Sea McMurdo Sound Taylor Valley McMurdo Ice Shelf Drygalski Drygalski Ice Tongue Bernacchi Cape Bernacchi Spike Cape |
genre |
Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf McMurdo Sound Ross Sea Sea ice |
genre_facet |
Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf McMurdo Sound Ross Sea Sea ice |
op_relation |
https://figshare.com/articles/thesis/Sedimentology_and_numerical_modelling_of_aeolian_sediment_dispersal_McMurdo_Sound_southwest_Ross_Sea_Antarctica/17005975 doi:10.26686/wgtn.17005975.v1 |
op_rights |
Author Retains Copyright |
op_doi |
https://doi.org/10.26686/wgtn.17005975.v1 |
_version_ |
1766096838744604672 |