Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change
Antarctic debris-covered glaciers are potential archives of long-term climate change. However, the geomorphic response of these systems to climate forcing is not well understood. To address this concern, I conducted a series of field-based and numerical modeling studies in the McMurdo Dry Valleys of...
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ftbostonuniv:oai:open.bu.edu:2144/14508 2023-05-15T13:50:53+02:00 Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change Mackay, Sean Leland 2016-02-13T02:21:08Z https://hdl.handle.net/2144/14508 en_US eng https://hdl.handle.net/2144/14508 Attribution-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nd/4.0/ CC-BY-ND Geomorphology Antarctica Climate change Cosmogenic nuclide dating Debris-covered glacier Ground-penetrating radar Orbital forcing Thesis/Dissertation 2016 ftbostonuniv 2022-07-11T11:50:19Z Antarctic debris-covered glaciers are potential archives of long-term climate change. However, the geomorphic response of these systems to climate forcing is not well understood. To address this concern, I conducted a series of field-based and numerical modeling studies in the McMurdo Dry Valleys of Antarctica (MDV), with a focus on Mullins and Friedman glaciers. I used data and results from geophysical surveys, ice-core collection and analysis, geomorphic mapping, micro-meteorological stations, and numerical-process models to (1) determine the precise origin and distribution of englacial and supraglacial debris within these buried-ice systems, (2) quantify the fundamental processes and feedbacks that govern interactions among englacial and supraglacial debris, (3) establish a process-based model to quantify the inventory of cosmogenic nuclides within englacial and supraglacial debris, and (4) isolate the governing relationships between the evolution of englacial /supraglacial debris and regional climate forcing. Results from 93 field excavations, 21 ice cores, and 24 km of ground-penetrating radar data show that Mullins and Friedman glaciers contain vast areas of clean glacier ice interspersed with inclined layers of concentrated debris. The similarity in the pattern of englacial debris bands across both glaciers, along with model results that call for negligible basal entrainment, is best explained by episodic environmental change at valley headwalls. To constrain better the timing of debris-band formation, I developed a modeling framework that tracks the accumulation of cosmogenic 3He in englacial and supraglacial debris. Results imply that ice within Mullins Glacier increases in age non-linearly from 12 ka to ~220 ka in areas of active flow (up to >> 1.6 Ma in areas of slow-moving-to-stagnant ice) and that englacial debris bands originate with a periodicity of ~41 ka. Modeling studies suggest that debris bands originate in synchronicity with changes in obliquity-paced, total integrated summer ... Thesis Antarc* Antarctic Antarctica ice core McMurdo Dry Valleys Boston University: OpenBU Antarctic McMurdo Dry Valleys |
institution |
Open Polar |
collection |
Boston University: OpenBU |
op_collection_id |
ftbostonuniv |
language |
English |
topic |
Geomorphology Antarctica Climate change Cosmogenic nuclide dating Debris-covered glacier Ground-penetrating radar Orbital forcing |
spellingShingle |
Geomorphology Antarctica Climate change Cosmogenic nuclide dating Debris-covered glacier Ground-penetrating radar Orbital forcing Mackay, Sean Leland Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change |
topic_facet |
Geomorphology Antarctica Climate change Cosmogenic nuclide dating Debris-covered glacier Ground-penetrating radar Orbital forcing |
description |
Antarctic debris-covered glaciers are potential archives of long-term climate change. However, the geomorphic response of these systems to climate forcing is not well understood. To address this concern, I conducted a series of field-based and numerical modeling studies in the McMurdo Dry Valleys of Antarctica (MDV), with a focus on Mullins and Friedman glaciers. I used data and results from geophysical surveys, ice-core collection and analysis, geomorphic mapping, micro-meteorological stations, and numerical-process models to (1) determine the precise origin and distribution of englacial and supraglacial debris within these buried-ice systems, (2) quantify the fundamental processes and feedbacks that govern interactions among englacial and supraglacial debris, (3) establish a process-based model to quantify the inventory of cosmogenic nuclides within englacial and supraglacial debris, and (4) isolate the governing relationships between the evolution of englacial /supraglacial debris and regional climate forcing. Results from 93 field excavations, 21 ice cores, and 24 km of ground-penetrating radar data show that Mullins and Friedman glaciers contain vast areas of clean glacier ice interspersed with inclined layers of concentrated debris. The similarity in the pattern of englacial debris bands across both glaciers, along with model results that call for negligible basal entrainment, is best explained by episodic environmental change at valley headwalls. To constrain better the timing of debris-band formation, I developed a modeling framework that tracks the accumulation of cosmogenic 3He in englacial and supraglacial debris. Results imply that ice within Mullins Glacier increases in age non-linearly from 12 ka to ~220 ka in areas of active flow (up to >> 1.6 Ma in areas of slow-moving-to-stagnant ice) and that englacial debris bands originate with a periodicity of ~41 ka. Modeling studies suggest that debris bands originate in synchronicity with changes in obliquity-paced, total integrated summer ... |
format |
Thesis |
author |
Mackay, Sean Leland |
author_facet |
Mackay, Sean Leland |
author_sort |
Mackay, Sean Leland |
title |
Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change |
title_short |
Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change |
title_full |
Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change |
title_fullStr |
Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change |
title_full_unstemmed |
Age, origin and evolution of Antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change |
title_sort |
age, origin and evolution of antarctic debris-covered glaciers: implications for landscape evolution and long-term climate change |
publishDate |
2016 |
url |
https://hdl.handle.net/2144/14508 |
geographic |
Antarctic McMurdo Dry Valleys |
geographic_facet |
Antarctic McMurdo Dry Valleys |
genre |
Antarc* Antarctic Antarctica ice core McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctic Antarctica ice core McMurdo Dry Valleys |
op_relation |
https://hdl.handle.net/2144/14508 |
op_rights |
Attribution-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nd/4.0/ |
op_rightsnorm |
CC-BY-ND |
_version_ |
1766254246148177920 |