Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada
Constraining the timing of past ice-sheet change is important for assessing the cryospheric expression of climate change and improving our understanding of ice sheet dynamics. Geochronology used to construct past ice-sheet reconstructions, however, can be ineffective in polar environments where ice...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
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Elsevier
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/38607 |
| _version_ | 1848755366257491968 |
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| author | Briner, J. Lifton, N. Miller, Gifford Refsnider, K. Anderson, R. Finkel, R. |
| author_facet | Briner, J. Lifton, N. Miller, Gifford Refsnider, K. Anderson, R. Finkel, R. |
| author_sort | Briner, J. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Constraining the timing of past ice-sheet change is important for assessing the cryospheric expression of climate change and improving our understanding of ice sheet dynamics. Geochronology used to construct past ice-sheet reconstructions, however, can be ineffective in polar environments where ice sheets were polythermal and left varying imprints on landscapes. Cosmogenic-nuclide exposure dating, for example, is especially hampered by the lack of ice-sheet erosion and resultant cosmogenic nuclide inheritance. Here, we apply in situ cosmogenic 10Be, 14C and 26Al methods to decipher various elements of the Laurentide Ice Sheet history of north-central Baffin Island. A clearly defined erosion boundary across the landscape reveals the transition in basal ice-sheet conditions as ice flow became channelized into northern Baffin Island fiords. 10Be and 26Al concentrations indicate that the boundary represents a juxtaposition of sliding, erosive ice and cold-bedded ice that preserved ancient bedrock that has not been significantly impacted by the ice sheet in perhaps one to two million years.We combine 10Be measurements from ice-sculpted bedrock with measurements of in situ14C, which has no inheritance due to its quick decay during ice-sheet cover, to determine the local timing of deglaciation. The average 10Be and in situ14C ages for upland deglaciation in north-central Baffin Island are 7.7 ± 0.9 and 8.4 ± 1.4 ka, respectively. Finally, in situ14C measurements from surfaces being uncovered by present-day retreat of small ice caps mantling uplands within the study area have concentrations too low to be compatible with continuous post-glacial exposure. These samples require shielding by ice for a significant portion of the Holocene, and more burial than during the Little Ice Age alone. Simple exposure-burial modeling suggests that 2400–2900 yr of total ice cover during Neoglaciation is required to explain measured in situ14C inventories. Combined, multiple cosmogenic nuclides with varying half-lives can be used to decipher many aspects of the history in landscapes occupied by polythermal ice sheets. |
| first_indexed | 2025-11-14T08:55:10Z |
| format | Journal Article |
| id | curtin-20.500.11937-38607 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:55:10Z |
| publishDate | 2014 |
| publisher | Elsevier |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-386072017-09-13T15:59:12Z Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada Briner, J. Lifton, N. Miller, Gifford Refsnider, K. Anderson, R. Finkel, R. 10Be dating Cosmogenic nuclide In situ 14C Baffin Island Polythermal ice sheet Constraining the timing of past ice-sheet change is important for assessing the cryospheric expression of climate change and improving our understanding of ice sheet dynamics. Geochronology used to construct past ice-sheet reconstructions, however, can be ineffective in polar environments where ice sheets were polythermal and left varying imprints on landscapes. Cosmogenic-nuclide exposure dating, for example, is especially hampered by the lack of ice-sheet erosion and resultant cosmogenic nuclide inheritance. Here, we apply in situ cosmogenic 10Be, 14C and 26Al methods to decipher various elements of the Laurentide Ice Sheet history of north-central Baffin Island. A clearly defined erosion boundary across the landscape reveals the transition in basal ice-sheet conditions as ice flow became channelized into northern Baffin Island fiords. 10Be and 26Al concentrations indicate that the boundary represents a juxtaposition of sliding, erosive ice and cold-bedded ice that preserved ancient bedrock that has not been significantly impacted by the ice sheet in perhaps one to two million years.We combine 10Be measurements from ice-sculpted bedrock with measurements of in situ14C, which has no inheritance due to its quick decay during ice-sheet cover, to determine the local timing of deglaciation. The average 10Be and in situ14C ages for upland deglaciation in north-central Baffin Island are 7.7 ± 0.9 and 8.4 ± 1.4 ka, respectively. Finally, in situ14C measurements from surfaces being uncovered by present-day retreat of small ice caps mantling uplands within the study area have concentrations too low to be compatible with continuous post-glacial exposure. These samples require shielding by ice for a significant portion of the Holocene, and more burial than during the Little Ice Age alone. Simple exposure-burial modeling suggests that 2400–2900 yr of total ice cover during Neoglaciation is required to explain measured in situ14C inventories. Combined, multiple cosmogenic nuclides with varying half-lives can be used to decipher many aspects of the history in landscapes occupied by polythermal ice sheets. 2014 Journal Article http://hdl.handle.net/20.500.11937/38607 10.1016/j.quageo.2012.11.005 Elsevier restricted |
| spellingShingle | 10Be dating Cosmogenic nuclide In situ 14C Baffin Island Polythermal ice sheet Briner, J. Lifton, N. Miller, Gifford Refsnider, K. Anderson, R. Finkel, R. Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada |
| title | Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada |
| title_full | Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada |
| title_fullStr | Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada |
| title_full_unstemmed | Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada |
| title_short | Using in situ cosmogenic 10Be, 14C, and 26Al to decipher the history of polythermal ice sheets on Baffin Island, Arctic Canada |
| title_sort | using in situ cosmogenic 10be, 14c, and 26al to decipher the history of polythermal ice sheets on baffin island, arctic canada |
| topic | 10Be dating Cosmogenic nuclide In situ 14C Baffin Island Polythermal ice sheet |
| url | http://hdl.handle.net/20.500.11937/38607 |