Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvance
<p>Unambiguous identification of past episodes of ice sheet thinning below the modern surface and grounding line retreat inboard of present requires recovery and exposure dating of subglacial bedrock. Such efforts are needed to understand the significance and potential future reversibility of...
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Copernicus Publications
2025-01-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/19/303/2025/tc-19-303-2025.pdf |
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| author | J. S. Johnson J. Woodward I. Nesbitt K. Winter S. Campbell K. A. Nichols R. A. Venturelli S. Braddock B. M. Goehring B. Hall D. H. Rood G. Balco G. Balco |
| author_facet | J. S. Johnson J. Woodward I. Nesbitt K. Winter S. Campbell K. A. Nichols R. A. Venturelli S. Braddock B. M. Goehring B. Hall D. H. Rood G. Balco G. Balco |
| author_sort | J. S. Johnson |
| collection | DOAJ |
| description | <p>Unambiguous identification of past episodes of ice sheet thinning below the modern surface and grounding line retreat inboard of present requires recovery and exposure dating of subglacial bedrock. Such efforts are needed to understand the significance and potential future reversibility of ongoing and projected change in Antarctica. Here we evaluate the suitability for subglacial bedrock drilling of sites in the Hudson Mountains, which are located in the Amundsen Sea sector of West Antarctica. We use an ice sheet model and field data – geological observations, glaciological observations and bedrock samples from nunataks, and ground-penetrating radar from subglacial ridges – to rate each site against four key criteria: (i) presence of ridges extending below the ice sheet, (ii) likelihood of increased exposure of those ridges if the grounding line was inboard of present, (iii) suitability of bedrock for drilling and geochemical analysis, and (iv) accessibility for aircraft and drilling operations. Our results demonstrate that although no site in the Hudson Mountains is perfect for this study when assessed against all criteria, the accessibility, N–S orientation and basaltic bedrock lithology of Winkie Nunatak's southernmost ridge (74.86° S, 99.77° W) make it a feasible site both for drilling and subsequent cosmogenic nuclide analysis. Furthermore, the ridge is strewn with glacial erratics at all elevations, providing valuable constraints on its early Holocene deglacial history. Based on our experiences during this study, we conclude with a series of recommendations for assessing site suitability for future bedrock drilling campaigns. We emphasise the importance of consulting a range of expertise prior to drilling and ensuring that sufficient field reconnaissance is undertaken (including obtaining detailed grids of radar survey data and bedrock samples).</p> |
| format | Article |
| id | doaj-art-c97c3668475b486f8360a204c152cc19 |
| institution | Kabale University |
| issn | 1994-0416 1994-0424 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj-art-c97c3668475b486f8360a204c152cc192025-01-24T15:47:37ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242025-01-011930332410.5194/tc-19-303-2025Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvanceJ. S. Johnson0J. Woodward1I. Nesbitt2K. Winter3S. Campbell4K. A. Nichols5R. A. Venturelli6S. Braddock7B. M. Goehring8B. Hall9D. H. Rood10G. Balco11G. Balco12British Antarctic Survey, Cambridge, CB3 0ET, UKDepartment of Geography and Environmental Sciences, Northumbria University, Newcastle-upon-Tyne, NE1 8ST, UKSchool of Earth and Climate Sciences and the Climate Change Institute, University of Maine, Orono, ME 04469, USADepartment of Geography and Environmental Sciences, Northumbria University, Newcastle-upon-Tyne, NE1 8ST, UKSchool of Earth and Climate Sciences and the Climate Change Institute, University of Maine, Orono, ME 04469, USADepartment of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, UKDepartment of Geology and Geological Engineering, Colorado School of Mines, Golden, CO 80401, USASchool of Earth and Climate Sciences and the Climate Change Institute, University of Maine, Orono, ME 04469, USALos Alamos National Laboratory, Los Alamos, NM 87545, USASchool of Earth and Climate Sciences and the Climate Change Institute, University of Maine, Orono, ME 04469, USADepartment of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, UKLawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551, USABerkeley Geochronology Center, Berkeley, CA 94709, USA<p>Unambiguous identification of past episodes of ice sheet thinning below the modern surface and grounding line retreat inboard of present requires recovery and exposure dating of subglacial bedrock. Such efforts are needed to understand the significance and potential future reversibility of ongoing and projected change in Antarctica. Here we evaluate the suitability for subglacial bedrock drilling of sites in the Hudson Mountains, which are located in the Amundsen Sea sector of West Antarctica. We use an ice sheet model and field data – geological observations, glaciological observations and bedrock samples from nunataks, and ground-penetrating radar from subglacial ridges – to rate each site against four key criteria: (i) presence of ridges extending below the ice sheet, (ii) likelihood of increased exposure of those ridges if the grounding line was inboard of present, (iii) suitability of bedrock for drilling and geochemical analysis, and (iv) accessibility for aircraft and drilling operations. Our results demonstrate that although no site in the Hudson Mountains is perfect for this study when assessed against all criteria, the accessibility, N–S orientation and basaltic bedrock lithology of Winkie Nunatak's southernmost ridge (74.86° S, 99.77° W) make it a feasible site both for drilling and subsequent cosmogenic nuclide analysis. Furthermore, the ridge is strewn with glacial erratics at all elevations, providing valuable constraints on its early Holocene deglacial history. Based on our experiences during this study, we conclude with a series of recommendations for assessing site suitability for future bedrock drilling campaigns. We emphasise the importance of consulting a range of expertise prior to drilling and ensuring that sufficient field reconnaissance is undertaken (including obtaining detailed grids of radar survey data and bedrock samples).</p>https://tc.copernicus.org/articles/19/303/2025/tc-19-303-2025.pdf |
| spellingShingle | J. S. Johnson J. Woodward I. Nesbitt K. Winter S. Campbell K. A. Nichols R. A. Venturelli S. Braddock B. M. Goehring B. Hall D. H. Rood G. Balco G. Balco Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvance The Cryosphere |
| title | Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvance |
| title_full | Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvance |
| title_fullStr | Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvance |
| title_full_unstemmed | Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvance |
| title_short | Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat–readvance |
| title_sort | assessing the suitability of sites near pine island glacier for subglacial bedrock drilling aimed at detecting holocene retreat readvance |
| url | https://tc.copernicus.org/articles/19/303/2025/tc-19-303-2025.pdf |
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