In situ 10 Be 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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Published in:The Cryosphere
Main Authors: B. L. Graham, J. P. Briner, N. E. Young, A. Balter-Kennedy, M. Koppes, J. M. Schaefer, K. Poinar, E. K. Thomas
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2023
Subjects:
Online Access:https://doi.org/10.5194/tc-17-4535-2023
https://doaj.org/article/aecc9315c9b84b58a6b961d283bf9ccf
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spelling ftdoajarticles:oai:doaj.org/article:aecc9315c9b84b58a6b961d283bf9ccf 2023-12-03T10:23:04+01:00 In situ 10 Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland B. L. Graham J. P. Briner N. E. Young A. Balter-Kennedy M. Koppes J. M. Schaefer K. Poinar E. K. Thomas 2023-10-01T00:00:00Z https://doi.org/10.5194/tc-17-4535-2023 https://doaj.org/article/aecc9315c9b84b58a6b961d283bf9ccf EN eng Copernicus Publications https://tc.copernicus.org/articles/17/4535/2023/tc-17-4535-2023.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-17-4535-2023 1994-0416 1994-0424 https://doaj.org/article/aecc9315c9b84b58a6b961d283bf9ccf The Cryosphere, Vol 17, Pp 4535-4547 (2023) Environmental sciences GE1-350 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5194/tc-17-4535-2023 2023-11-05T01:42:30Z 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. Article in Journal/Newspaper glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ Kujalleq Sermeq Kujalleq The Cryosphere Directory of Open Access Journals: DOAJ Articles 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 Directory of Open Access Journals: DOAJ Articles
op_collection_id ftdoajarticles
language English
topic Environmental sciences
GE1-350
Geology
QE1-996.5
spellingShingle Environmental sciences
GE1-350
Geology
QE1-996.5
B. L. Graham
J. P. Briner
N. E. Young
A. Balter-Kennedy
M. Koppes
J. M. Schaefer
K. Poinar
E. K. Thomas
In situ 10 Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland
topic_facet Environmental sciences
GE1-350
Geology
QE1-996.5
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 Article in Journal/Newspaper
author B. L. Graham
J. P. Briner
N. E. Young
A. Balter-Kennedy
M. Koppes
J. M. Schaefer
K. Poinar
E. K. Thomas
author_facet B. L. Graham
J. P. Briner
N. E. Young
A. Balter-Kennedy
M. Koppes
J. M. Schaefer
K. Poinar
E. K. Thomas
author_sort B. L. Graham
title In situ 10 Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland
title_short In situ 10 Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland
title_full In situ 10 Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland
title_fullStr In situ 10 Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland
title_full_unstemmed In situ 10 Be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at Sermeq Kujalleq (Jakobshavn Isbræ), Greenland
title_sort in situ 10 be modeling and terrain analysis constrain subglacial quarrying and abrasion rates at sermeq kujalleq (jakobshavn isbræ), greenland
publisher Copernicus Publications
publishDate 2023
url https://doi.org/10.5194/tc-17-4535-2023
https://doaj.org/article/aecc9315c9b84b58a6b961d283bf9ccf
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
The Cryosphere
genre_facet glacier
Greenland
Ice Sheet
Jakobshavn
Jakobshavn isbræ
Kujalleq
Sermeq Kujalleq
The Cryosphere
op_source The Cryosphere, Vol 17, Pp 4535-4547 (2023)
op_relation https://tc.copernicus.org/articles/17/4535/2023/tc-17-4535-2023.pdf
https://doaj.org/toc/1994-0416
https://doaj.org/toc/1994-0424
doi:10.5194/tc-17-4535-2023
1994-0416
1994-0424
https://doaj.org/article/aecc9315c9b84b58a6b961d283bf9ccf
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
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