On active layer processes and landforms in western Dronning Maud Land, Antarctica
- Authors: Scott, David Alan
- Date: 2015
- Subjects: Landforms -- Antarctica -- Queen Maud Land , Permafrost -- Antarctica -- Queen Maud Land , Permafrost -- Thermal properties -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Cryosphere , Drone aircraft -- Antarctica -- Queen Maud Land , 3-D modeling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4893 , http://hdl.handle.net/10962/d1019757
- Description: Permafrost is a variable in Antarctic terrestrial ecosystems, and the role it plays in the cryosphere is not well understood. There is much still to be learnt about the thermal state, physical properties, thickness and age of permafrost in Western Dronning Maud Land (WDML). Active layer dynamics and observed change over time have the potential to improve our knowledge of climate change. Understanding the effects of a warming climate on permafrost can also be of benefit to infrastructure, especially in areas with a large amount of frozen ground such as Scandinavia, Canada and Russia. Active layer and permafrost dynamics of WDML, Antarctica, are presented and discussed using data from six study sites, namely the Robertskollen, Vesleskarvet, Flarjuven, Grunehogna, Slettjfell nunataks and the Troll research station in the Jutulsessen area. Ground and ambient air temperature, as well as ground moisture data were collected for each site. An inventory of active layer and permafrost landforms was compiled, as were the frequency of cycles over the zero-degree isotherm, and the depth of the active layer. Furthermore, 3D models, geo-referenced maps and Digital Elevation Models were created of study areas with the use of an Unmanned Aerial Vehicle (UAV). Polygonal features are the most common landscape feature and are common to most of the study sites. Robertskollen has the deepest active layer at over 66cm and Slettfjell the shallowest at 9cm. A maximum recorded air temperature of 8.76°C (10/11/2014) occurred at Troll with the second highest maximum of 6.77°C (22/12/2010) recorded at Vesleskarvet. Robertskollen has the highest observable biological growth and a maximum recorded ground temperature of 22.84°C (10/01/2014). Troll and Valterkulten, registered the second and third highest ground temperatures respectively. The high ground Temperature observed for Robertskollen may be ascribed to it being the lowest altitude site. The highest number of cycles over the zero-degree isotherm was observed at Troll (11.01%), followed by Robertskollen (10.99%). For relatively warm areas, such as Robertskollen it is recommended that two metre borehole loggers are installed in order to capture a detailed understanding of the active layer. The UAV proved to be a beneficial tool for capturing aerial photographs for post fieldwork analysis and 3D modelling.
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- Authors: Scott, David Alan
- Date: 2015
- Subjects: Landforms -- Antarctica -- Queen Maud Land , Permafrost -- Antarctica -- Queen Maud Land , Permafrost -- Thermal properties -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Cryosphere , Drone aircraft -- Antarctica -- Queen Maud Land , 3-D modeling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4893 , http://hdl.handle.net/10962/d1019757
- Description: Permafrost is a variable in Antarctic terrestrial ecosystems, and the role it plays in the cryosphere is not well understood. There is much still to be learnt about the thermal state, physical properties, thickness and age of permafrost in Western Dronning Maud Land (WDML). Active layer dynamics and observed change over time have the potential to improve our knowledge of climate change. Understanding the effects of a warming climate on permafrost can also be of benefit to infrastructure, especially in areas with a large amount of frozen ground such as Scandinavia, Canada and Russia. Active layer and permafrost dynamics of WDML, Antarctica, are presented and discussed using data from six study sites, namely the Robertskollen, Vesleskarvet, Flarjuven, Grunehogna, Slettjfell nunataks and the Troll research station in the Jutulsessen area. Ground and ambient air temperature, as well as ground moisture data were collected for each site. An inventory of active layer and permafrost landforms was compiled, as were the frequency of cycles over the zero-degree isotherm, and the depth of the active layer. Furthermore, 3D models, geo-referenced maps and Digital Elevation Models were created of study areas with the use of an Unmanned Aerial Vehicle (UAV). Polygonal features are the most common landscape feature and are common to most of the study sites. Robertskollen has the deepest active layer at over 66cm and Slettfjell the shallowest at 9cm. A maximum recorded air temperature of 8.76°C (10/11/2014) occurred at Troll with the second highest maximum of 6.77°C (22/12/2010) recorded at Vesleskarvet. Robertskollen has the highest observable biological growth and a maximum recorded ground temperature of 22.84°C (10/01/2014). Troll and Valterkulten, registered the second and third highest ground temperatures respectively. The high ground Temperature observed for Robertskollen may be ascribed to it being the lowest altitude site. The highest number of cycles over the zero-degree isotherm was observed at Troll (11.01%), followed by Robertskollen (10.99%). For relatively warm areas, such as Robertskollen it is recommended that two metre borehole loggers are installed in order to capture a detailed understanding of the active layer. The UAV proved to be a beneficial tool for capturing aerial photographs for post fieldwork analysis and 3D modelling.
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The characterisation of an openwork block deposit, northern buttress, Vesleskarvet, Dronning Maud Land, Antarctica.
- Authors: Hansen, Christel Dorothee
- Date: 2014
- Subjects: Formations (Geology) -- Antarctica -- Queen Maud Land , Geology, Structural -- Antarctica -- Queen Maud Land , Weathering -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Physical geography -- Antarctica -- Queen Maud Land , Paleoclimatology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4878 , http://hdl.handle.net/10962/d1013138
- Description: Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
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- Authors: Hansen, Christel Dorothee
- Date: 2014
- Subjects: Formations (Geology) -- Antarctica -- Queen Maud Land , Geology, Structural -- Antarctica -- Queen Maud Land , Weathering -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Physical geography -- Antarctica -- Queen Maud Land , Paleoclimatology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4878 , http://hdl.handle.net/10962/d1013138
- Description: Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
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