2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica
The PPG found in the Dry Valleys is some of the oldest on the planet with ages of up to 8 million years assigned to them. The activity of some of these Antarctic PPG areas has come into question with the proposal that they may be the result of sublimation processes rather than actively re-working fr...
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ftdatacite:10.26021/7355 2023-05-15T13:35:41+02:00 2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica Godfrey, Myfanwy Jane 2008 https://dx.doi.org/10.26021/7355 https://ir.canterbury.ac.nz/handle/10092/2255 unknown University of Canterbury. Geological Sciences Copyright Myfanwy Jane Godfrey https://canterbury.libguides.com/rights/theses CreativeWork article 2008 ftdatacite https://doi.org/10.26021/7355 2021-11-05T12:55:41Z The PPG found in the Dry Valleys is some of the oldest on the planet with ages of up to 8 million years assigned to them. The activity of some of these Antarctic PPG areas has come into question with the proposal that they may be the result of sublimation processes rather than actively re-working freeze and thaw processes. Near surface geophysical methods of ground penetrating radar (GPR), resistivity tomography and electromagnetism have been applied to four Antarctic Dry Valleys polygonal patterned ground (PPG) areas; two in Victoria Valley and two in Beacon Valley. The aim was to resolve subsurface structure and activity of the PPG without disturbing the delicate permafrost soils. Multiple techniques were used so that there could be greater reliability on the interpretations of this data without the need for damaging subsurface geological calibration of the geophysics by obtaining direct subsurface data through methods such as trenching or drilling. Subsurface structure of the PPG was resolved; active layer depth, deformation of permafrost in the vicinity of contraction cracks and zones of attenuation were identified. Significant deformation in the subsurface horizons of the permafrost and associated with thermal contraction crack wedge growth was identified over PPG suggested to be formed only by sublimation in Beacon Valley, thus calling into question this interpretation of the PPG activity. The most reliable identification of subsurface features occurred with correlation between GPR and resistivity tomography results. Article in Journal/Newspaper Antarc* Antarctic Antarctica McMurdo Dry Valleys permafrost wedge* DataCite Metadata Store (German National Library of Science and Technology) Antarctic McMurdo Dry Valleys Victoria Valley ENVELOPE(162.000,162.000,-77.383,-77.383) Beacon Valley ENVELOPE(160.650,160.650,-77.817,-77.817) |
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DataCite Metadata Store (German National Library of Science and Technology) |
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The PPG found in the Dry Valleys is some of the oldest on the planet with ages of up to 8 million years assigned to them. The activity of some of these Antarctic PPG areas has come into question with the proposal that they may be the result of sublimation processes rather than actively re-working freeze and thaw processes. Near surface geophysical methods of ground penetrating radar (GPR), resistivity tomography and electromagnetism have been applied to four Antarctic Dry Valleys polygonal patterned ground (PPG) areas; two in Victoria Valley and two in Beacon Valley. The aim was to resolve subsurface structure and activity of the PPG without disturbing the delicate permafrost soils. Multiple techniques were used so that there could be greater reliability on the interpretations of this data without the need for damaging subsurface geological calibration of the geophysics by obtaining direct subsurface data through methods such as trenching or drilling. Subsurface structure of the PPG was resolved; active layer depth, deformation of permafrost in the vicinity of contraction cracks and zones of attenuation were identified. Significant deformation in the subsurface horizons of the permafrost and associated with thermal contraction crack wedge growth was identified over PPG suggested to be formed only by sublimation in Beacon Valley, thus calling into question this interpretation of the PPG activity. The most reliable identification of subsurface features occurred with correlation between GPR and resistivity tomography results. |
format |
Article in Journal/Newspaper |
author |
Godfrey, Myfanwy Jane |
spellingShingle |
Godfrey, Myfanwy Jane 2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica |
author_facet |
Godfrey, Myfanwy Jane |
author_sort |
Godfrey, Myfanwy Jane |
title |
2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica |
title_short |
2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica |
title_full |
2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica |
title_fullStr |
2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica |
title_full_unstemmed |
2D and 3D Geophysical Imaging of Polygonal Patterned Ground in the McMurdo Dry Valleys, Antarctica |
title_sort |
2d and 3d geophysical imaging of polygonal patterned ground in the mcmurdo dry valleys, antarctica |
publisher |
University of Canterbury. Geological Sciences |
publishDate |
2008 |
url |
https://dx.doi.org/10.26021/7355 https://ir.canterbury.ac.nz/handle/10092/2255 |
long_lat |
ENVELOPE(162.000,162.000,-77.383,-77.383) ENVELOPE(160.650,160.650,-77.817,-77.817) |
geographic |
Antarctic McMurdo Dry Valleys Victoria Valley Beacon Valley |
geographic_facet |
Antarctic McMurdo Dry Valleys Victoria Valley Beacon Valley |
genre |
Antarc* Antarctic Antarctica McMurdo Dry Valleys permafrost wedge* |
genre_facet |
Antarc* Antarctic Antarctica McMurdo Dry Valleys permafrost wedge* |
op_rights |
Copyright Myfanwy Jane Godfrey https://canterbury.libguides.com/rights/theses |
op_doi |
https://doi.org/10.26021/7355 |
_version_ |
1766068880143286272 |