Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes
Subglacial chemical weathering plays a role in global silicate weathering budgets, contributing to the cycling of silicon (Si) in terrestrial and marine systems and the potential drawdown of carbon dioxide from the atmosphere. Here, we use data from two Greenland Ice Sheet (GrIS) catchments to demon...
Published in: | Geochimica et Cosmochimica Acta |
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2019
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Online Access: | https://hdl.handle.net/1983/43372b7d-b8f0-4f3b-9845-a6dd3a21f9ac https://research-information.bris.ac.uk/en/publications/43372b7d-b8f0-4f3b-9845-a6dd3a21f9ac https://doi.org/10.1016/j.gca.2018.12.033 https://research-information.bris.ac.uk/ws/files/204205831/Hatton_et_al_2019.pdf http://www.scopus.com/inward/record.url?scp=85059844783&partnerID=8YFLogxK |
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ftubristolcris:oai:research-information.bris.ac.uk:publications/43372b7d-b8f0-4f3b-9845-a6dd3a21f9ac 2024-01-28T10:05:55+01:00 Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, Marek Beaton, A. D. Bagshaw, E. A. Telling, J. 2019-02-15 application/pdf https://hdl.handle.net/1983/43372b7d-b8f0-4f3b-9845-a6dd3a21f9ac https://research-information.bris.ac.uk/en/publications/43372b7d-b8f0-4f3b-9845-a6dd3a21f9ac https://doi.org/10.1016/j.gca.2018.12.033 https://research-information.bris.ac.uk/ws/files/204205831/Hatton_et_al_2019.pdf http://www.scopus.com/inward/record.url?scp=85059844783&partnerID=8YFLogxK eng eng info:eu-repo/grantAgreement/EC/H2020/678371 info:eu-repo/semantics/openAccess Hatton , J E , Hendry , K R , Hawkings , J R , Wadham , J L , Kohler , T J , Stibal , M , Beaton , A D , Bagshaw , E A & Telling , J 2019 , ' Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes ' , Geochimica et Cosmochimica Acta , vol. 247 , pp. 191-206 . https://doi.org/10.1016/j.gca.2018.12.033 Silicon isotopes Subglacial Silicate Weathering Greenland article 2019 ftubristolcris https://doi.org/10.1016/j.gca.2018.12.033 2024-01-04T23:58:17Z Subglacial chemical weathering plays a role in global silicate weathering budgets, contributing to the cycling of silicon (Si) in terrestrial and marine systems and the potential drawdown of carbon dioxide from the atmosphere. Here, we use data from two Greenland Ice Sheet (GrIS) catchments to demonstrate how Si isotopes from dissolved and amorphous particulate fractions (δ30DSi and δ30ASi respectively) can be used together with major ion data to assess the degree of secondary silicate weathering product formation and redissolution in subglacial environments. We compare a time-series of summer melt seasons from the two study sites, which differ in catchment size (~600 km2 for Leverett Glacier (LG) and ~36 km2 for Kiattuut Sermiat (KS)). Subglacial waters from LG have elevated Na+ and K+ ions in relation to Ca2+ and Mg2+ ions, indicating a predominance of silicate weathering, whilst meltwaters from KS are characterised by carbonate hydrolysis weathering (hydrolysis and carbonation) throughout the melt season. Both catchments have mean δ30DSi values substantially lower than average riverine values (KS 0.41‰, LG -0.25‰, versus a global riverine mean of 1.25‰) and display a seasonal decline, which is more pronounced at LG. The δ30ASi values (discharge weighted mean values KS -0.44‰, LG -0.22‰) are lighter than the bedrock (mean values KS -0.18±0.12‰, LG 0.00±0.07‰) in both catchments, indicating a secondary weathering product origin or leaching of lighter isotopes during initial weathering of crushed rock. When used in combination, the major ion and silicon isotope data reveal that the extent of silicate weathering and secondary phase redissolution in the two catchments is different, with both being more pronounced at LG. Contrasting weathering regimes and subglacial hydrology between catchments need to be considered when estimating the δ30Si composition of silica exported into polar oceans from the GrIS, with larger catchments likely to produce fluxes of lighter δ30Si. As larger catchments dominate freshwater ... Article in Journal/Newspaper glacier Greenland Ice Sheet Leverett Glacier University of Bristol: Bristol Research Greenland Kiattuut Sermiat ENVELOPE(-45.267,-45.267,61.267,61.267) Leverett Glacier ENVELOPE(-147.583,-147.583,-85.633,-85.633) Geochimica et Cosmochimica Acta 247 191 206 |
institution |
Open Polar |
collection |
University of Bristol: Bristol Research |
op_collection_id |
ftubristolcris |
language |
English |
topic |
Silicon isotopes Subglacial Silicate Weathering Greenland |
spellingShingle |
Silicon isotopes Subglacial Silicate Weathering Greenland Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, Marek Beaton, A. D. Bagshaw, E. A. Telling, J. Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
topic_facet |
Silicon isotopes Subglacial Silicate Weathering Greenland |
description |
Subglacial chemical weathering plays a role in global silicate weathering budgets, contributing to the cycling of silicon (Si) in terrestrial and marine systems and the potential drawdown of carbon dioxide from the atmosphere. Here, we use data from two Greenland Ice Sheet (GrIS) catchments to demonstrate how Si isotopes from dissolved and amorphous particulate fractions (δ30DSi and δ30ASi respectively) can be used together with major ion data to assess the degree of secondary silicate weathering product formation and redissolution in subglacial environments. We compare a time-series of summer melt seasons from the two study sites, which differ in catchment size (~600 km2 for Leverett Glacier (LG) and ~36 km2 for Kiattuut Sermiat (KS)). Subglacial waters from LG have elevated Na+ and K+ ions in relation to Ca2+ and Mg2+ ions, indicating a predominance of silicate weathering, whilst meltwaters from KS are characterised by carbonate hydrolysis weathering (hydrolysis and carbonation) throughout the melt season. Both catchments have mean δ30DSi values substantially lower than average riverine values (KS 0.41‰, LG -0.25‰, versus a global riverine mean of 1.25‰) and display a seasonal decline, which is more pronounced at LG. The δ30ASi values (discharge weighted mean values KS -0.44‰, LG -0.22‰) are lighter than the bedrock (mean values KS -0.18±0.12‰, LG 0.00±0.07‰) in both catchments, indicating a secondary weathering product origin or leaching of lighter isotopes during initial weathering of crushed rock. When used in combination, the major ion and silicon isotope data reveal that the extent of silicate weathering and secondary phase redissolution in the two catchments is different, with both being more pronounced at LG. Contrasting weathering regimes and subglacial hydrology between catchments need to be considered when estimating the δ30Si composition of silica exported into polar oceans from the GrIS, with larger catchments likely to produce fluxes of lighter δ30Si. As larger catchments dominate freshwater ... |
format |
Article in Journal/Newspaper |
author |
Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, Marek Beaton, A. D. Bagshaw, E. A. Telling, J. |
author_facet |
Hatton, J. E. Hendry, K. R. Hawkings, J. R. Wadham, J. L. Kohler, T. J. Stibal, Marek Beaton, A. D. Bagshaw, E. A. Telling, J. |
author_sort |
Hatton, J. E. |
title |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_short |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_full |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_fullStr |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_full_unstemmed |
Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes |
title_sort |
investigation of subglacial weathering under the greenland ice sheet using silicon isotopes |
publishDate |
2019 |
url |
https://hdl.handle.net/1983/43372b7d-b8f0-4f3b-9845-a6dd3a21f9ac https://research-information.bris.ac.uk/en/publications/43372b7d-b8f0-4f3b-9845-a6dd3a21f9ac https://doi.org/10.1016/j.gca.2018.12.033 https://research-information.bris.ac.uk/ws/files/204205831/Hatton_et_al_2019.pdf http://www.scopus.com/inward/record.url?scp=85059844783&partnerID=8YFLogxK |
long_lat |
ENVELOPE(-45.267,-45.267,61.267,61.267) ENVELOPE(-147.583,-147.583,-85.633,-85.633) |
geographic |
Greenland Kiattuut Sermiat Leverett Glacier |
geographic_facet |
Greenland Kiattuut Sermiat Leverett Glacier |
genre |
glacier Greenland Ice Sheet Leverett Glacier |
genre_facet |
glacier Greenland Ice Sheet Leverett Glacier |
op_source |
Hatton , J E , Hendry , K R , Hawkings , J R , Wadham , J L , Kohler , T J , Stibal , M , Beaton , A D , Bagshaw , E A & Telling , J 2019 , ' Investigation of subglacial weathering under the Greenland Ice Sheet using silicon isotopes ' , Geochimica et Cosmochimica Acta , vol. 247 , pp. 191-206 . https://doi.org/10.1016/j.gca.2018.12.033 |
op_relation |
info:eu-repo/grantAgreement/EC/H2020/678371 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.gca.2018.12.033 |
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Geochimica et Cosmochimica Acta |
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247 |
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191 |
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1789332482268594176 |