In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland
Glacial erosion creates diagnostic landscapes and vast amounts of sediment. However, knowledge about the rate at which glaciers erode and sculpt bedrock and the proportion of quarried (plucked) versus abraded material is limited. To address this, we quantify subglacial erosion rates and constrain th...
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ftcopernicus:oai:publications.copernicus.org:tc111142 2023-12-03T10:23:04+01:00 In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland Graham, Brandon L. Briner, Jason P. Young, Nicolás E. Balter-Kennedy, Allie Koppes, Michele Schaefer, Joerg M. Poinar, Kristin Thomas, Elizabeth K. 2023-10-30 application/pdf https://doi.org/10.5194/tc-17-4535-2023 https://tc.copernicus.org/articles/17/4535/2023/ eng eng doi:10.5194/tc-17-4535-2023 https://tc.copernicus.org/articles/17/4535/2023/ eISSN: 1994-0424 Text 2023 ftcopernicus https://doi.org/10.5194/tc-17-4535-2023 2023-11-06T17:24:16Z Glacial erosion creates diagnostic landscapes and vast amounts of sediment. However, knowledge about the rate at which glaciers erode and sculpt bedrock and the proportion of quarried (plucked) versus abraded material is limited. To address this, we quantify subglacial erosion rates and constrain the ratio of quarrying to abrasion during a recent, ∼ 200-year long overriding of a bedrock surface fronting, Sermeq Kujalleq (Jakobshavn Isbræ), Greenland, by combining 10 Be analyses, a digital terrain model, and field observations. Cosmogenic 10 Be measurements along a 1.2 m tall quarried bedrock step reveal a triangular wedge of quarried rock. Using individual 10 Be measurements from abraded surfaces across the study area, we derive an average abrasion rate of 0.13 ± 0.08 mm yr −1 . By applying this analysis across a ∼ 1.33 km 2 study area, we estimate that the Greenland Ice Sheet quarried 378 ± 45 m 3 and abraded 322 ± 204 m 3 of material at this site. These values result in an average total erosion rate of 0.26 ± 0.16 mm yr −1 , with abrasion and quarrying contributing in roughly equal proportions within uncertainty. Additional cosmogenic 10 Be analysis and surface texture mapping indicate that many lee steps are relicts from the prior glaciation and were not re-quarried during the recent overriding event. These new observations of glacier erosion in a recently exposed landscape provide one of the first direct measurements of quarrying rates and indicate that quarrying accounts for roughly half of the total glacial erosion in representative continental shield lithologies. Text glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ Kujalleq Sermeq Kujalleq Copernicus Publications: E-Journals Greenland Jakobshavn Isbræ ENVELOPE(-49.917,-49.917,69.167,69.167) Kujalleq ENVELOPE(-46.037,-46.037,60.719,60.719) The Cryosphere 17 11 4535 4547 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Glacial erosion creates diagnostic landscapes and vast amounts of sediment. However, knowledge about the rate at which glaciers erode and sculpt bedrock and the proportion of quarried (plucked) versus abraded material is limited. To address this, we quantify subglacial erosion rates and constrain the ratio of quarrying to abrasion during a recent, ∼ 200-year long overriding of a bedrock surface fronting, Sermeq Kujalleq (Jakobshavn Isbræ), Greenland, by combining 10 Be analyses, a digital terrain model, and field observations. Cosmogenic 10 Be measurements along a 1.2 m tall quarried bedrock step reveal a triangular wedge of quarried rock. Using individual 10 Be measurements from abraded surfaces across the study area, we derive an average abrasion rate of 0.13 ± 0.08 mm yr −1 . By applying this analysis across a ∼ 1.33 km 2 study area, we estimate that the Greenland Ice Sheet quarried 378 ± 45 m 3 and abraded 322 ± 204 m 3 of material at this site. These values result in an average total erosion rate of 0.26 ± 0.16 mm yr −1 , with abrasion and quarrying contributing in roughly equal proportions within uncertainty. Additional cosmogenic 10 Be analysis and surface texture mapping indicate that many lee steps are relicts from the prior glaciation and were not re-quarried during the recent overriding event. These new observations of glacier erosion in a recently exposed landscape provide one of the first direct measurements of quarrying rates and indicate that quarrying accounts for roughly half of the total glacial erosion in representative continental shield lithologies. |
format |
Text |
author |
Graham, Brandon L. Briner, Jason P. Young, Nicolás E. Balter-Kennedy, Allie Koppes, Michele Schaefer, Joerg M. Poinar, Kristin Thomas, Elizabeth K. |
spellingShingle |
Graham, Brandon L. Briner, Jason P. Young, Nicolás E. Balter-Kennedy, Allie Koppes, Michele Schaefer, Joerg M. Poinar, Kristin Thomas, Elizabeth K. In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland |
author_facet |
Graham, Brandon L. Briner, Jason P. Young, Nicolás E. Balter-Kennedy, Allie Koppes, Michele Schaefer, Joerg M. Poinar, Kristin Thomas, Elizabeth K. |
author_sort |
Graham, Brandon L. |
title |
In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland |
title_short |
In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland |
title_full |
In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland |
title_fullStr |
In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland |
title_full_unstemmed |
In situ 10Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland |
title_sort |
in situ 10be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at sermeq kujalleq (jakobshavn isbræ), greenland |
publishDate |
2023 |
url |
https://doi.org/10.5194/tc-17-4535-2023 https://tc.copernicus.org/articles/17/4535/2023/ |
long_lat |
ENVELOPE(-49.917,-49.917,69.167,69.167) ENVELOPE(-46.037,-46.037,60.719,60.719) |
geographic |
Greenland Jakobshavn Isbræ Kujalleq |
geographic_facet |
Greenland Jakobshavn Isbræ Kujalleq |
genre |
glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ Kujalleq Sermeq Kujalleq |
genre_facet |
glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ Kujalleq Sermeq Kujalleq |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-17-4535-2023 https://tc.copernicus.org/articles/17/4535/2023/ |
op_doi |
https://doi.org/10.5194/tc-17-4535-2023 |
container_title |
The Cryosphere |
container_volume |
17 |
container_issue |
11 |
container_start_page |
4535 |
op_container_end_page |
4547 |
_version_ |
1784271106406875136 |