Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments
Abstract This study reports stable and radiogenic strontium isotope behaviour in the dissolved load and suspended sediments from the subglacial outflow of the Lemon Creek glacier (Juneau Ice Field, Alaska) over a single melt season. In situ measurements (discharge, total alkalinity, pH and conductiv...
Published in: | Chemical Geology |
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Language: | English |
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2016
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Online Access: | https://hdl.handle.net/1983/803df102-633f-4818-8d60-7a4ffecc423c https://research-information.bris.ac.uk/en/publications/803df102-633f-4818-8d60-7a4ffecc423c https://doi.org/10.1016/j.chemgeo.2016.03.008 https://research-information.bris.ac.uk/ws/files/74379197/Stevenson_et_al_2016_finaledit.pdf http://www.sciencedirect.com/science/article/pii/S000925411630122X |
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ftubristolcris:oai:research-information.bris.ac.uk:publications/803df102-633f-4818-8d60-7a4ffecc423c 2024-05-19T07:40:40+00:00 Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments Stevenson, E.I. Aciego, S.M. Chutcharavan, P. Parkinson, I.J. Burton, K.W. Blakowski, M.A. Arendt, C.A. 2016-07-01 application/pdf https://hdl.handle.net/1983/803df102-633f-4818-8d60-7a4ffecc423c https://research-information.bris.ac.uk/en/publications/803df102-633f-4818-8d60-7a4ffecc423c https://doi.org/10.1016/j.chemgeo.2016.03.008 https://research-information.bris.ac.uk/ws/files/74379197/Stevenson_et_al_2016_finaledit.pdf http://www.sciencedirect.com/science/article/pii/S000925411630122X eng eng https://research-information.bris.ac.uk/en/publications/803df102-633f-4818-8d60-7a4ffecc423c info:eu-repo/semantics/openAccess Stevenson , E I , Aciego , S M , Chutcharavan , P , Parkinson , I J , Burton , K W , Blakowski , M A & Arendt , C A 2016 , ' Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments ' , Chemical Geology , vol. 429 , pp. 33-43 . https://doi.org/10.1016/j.chemgeo.2016.03.008 Strontium isotopes Stable strontium isotopes Weathering Subglacial environments article 2016 ftubristolcris https://doi.org/10.1016/j.chemgeo.2016.03.008 2024-04-23T23:50:28Z Abstract This study reports stable and radiogenic strontium isotope behaviour in the dissolved load and suspended sediments from the subglacial outflow of the Lemon Creek glacier (Juneau Ice Field, Alaska) over a single melt season. In situ measurements (discharge, total alkalinity, pH and conductivity) are combined with elemental concentrations, X-ray diffraction (XRD) analysis and radiogenic strontium isotope measurements to interpret the variations observed in stable strontium isotopic ratios. The stable Sr isotope composition (88Sr/86Sr ratio expressed as δ88/86Sr, ‰) of the dissolved load averages 0.31 ± 0.05‰, and is heavier than both the suspended sediment 0.18 ± 0.03‰, as well as local bedrocks ~ 0.20 to 0.26‰. We attribute the enrichment of heavier isotopes in the dissolved load to the uptake of lighter Sr isotopes by secondary weathering minerals, driving the dissolved load to heavier values. X-ray diffraction (XRD) analysis confirms the presence of clays in the suspended sediments and thermodynamic modelling suggests the presence of iron oxy-hydroxide phases. Although it is not possible to completely rule out the effect of dissolution of primary minerals in controlling Sr isotopic compositions of the dissolved load, our data indicate that the extent of secondary mineral formation likely plays a significant role. The preferential weathering of minerals such as biotite (consistent with the mineralogical assemblages found in the suspended sediments), as well as the potential presence of radiogenic calcites from metacarbonates (derived from the Yukon-Tanana terrain), may be driving the small seasonal shifts in 87Sr/86Sr of the dissolved load to more radiogenic compositions, from 87Sr/86Sr(DL) = 0.71048 to 0.710647. Using the combination of stable and radiogenic strontium isotopes to investigate weathering processes shows that radiogenic Sr isotopes provide information regarding weathering of primary phases. While the stable Sr isotope data appear to record information regarding the extent of secondary ... Article in Journal/Newspaper glacier Alaska Yukon University of Bristol: Bristol Research Chemical Geology 429 33 43 |
institution |
Open Polar |
collection |
University of Bristol: Bristol Research |
op_collection_id |
ftubristolcris |
language |
English |
topic |
Strontium isotopes Stable strontium isotopes Weathering Subglacial environments |
spellingShingle |
Strontium isotopes Stable strontium isotopes Weathering Subglacial environments Stevenson, E.I. Aciego, S.M. Chutcharavan, P. Parkinson, I.J. Burton, K.W. Blakowski, M.A. Arendt, C.A. Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments |
topic_facet |
Strontium isotopes Stable strontium isotopes Weathering Subglacial environments |
description |
Abstract This study reports stable and radiogenic strontium isotope behaviour in the dissolved load and suspended sediments from the subglacial outflow of the Lemon Creek glacier (Juneau Ice Field, Alaska) over a single melt season. In situ measurements (discharge, total alkalinity, pH and conductivity) are combined with elemental concentrations, X-ray diffraction (XRD) analysis and radiogenic strontium isotope measurements to interpret the variations observed in stable strontium isotopic ratios. The stable Sr isotope composition (88Sr/86Sr ratio expressed as δ88/86Sr, ‰) of the dissolved load averages 0.31 ± 0.05‰, and is heavier than both the suspended sediment 0.18 ± 0.03‰, as well as local bedrocks ~ 0.20 to 0.26‰. We attribute the enrichment of heavier isotopes in the dissolved load to the uptake of lighter Sr isotopes by secondary weathering minerals, driving the dissolved load to heavier values. X-ray diffraction (XRD) analysis confirms the presence of clays in the suspended sediments and thermodynamic modelling suggests the presence of iron oxy-hydroxide phases. Although it is not possible to completely rule out the effect of dissolution of primary minerals in controlling Sr isotopic compositions of the dissolved load, our data indicate that the extent of secondary mineral formation likely plays a significant role. The preferential weathering of minerals such as biotite (consistent with the mineralogical assemblages found in the suspended sediments), as well as the potential presence of radiogenic calcites from metacarbonates (derived from the Yukon-Tanana terrain), may be driving the small seasonal shifts in 87Sr/86Sr of the dissolved load to more radiogenic compositions, from 87Sr/86Sr(DL) = 0.71048 to 0.710647. Using the combination of stable and radiogenic strontium isotopes to investigate weathering processes shows that radiogenic Sr isotopes provide information regarding weathering of primary phases. While the stable Sr isotope data appear to record information regarding the extent of secondary ... |
format |
Article in Journal/Newspaper |
author |
Stevenson, E.I. Aciego, S.M. Chutcharavan, P. Parkinson, I.J. Burton, K.W. Blakowski, M.A. Arendt, C.A. |
author_facet |
Stevenson, E.I. Aciego, S.M. Chutcharavan, P. Parkinson, I.J. Burton, K.W. Blakowski, M.A. Arendt, C.A. |
author_sort |
Stevenson, E.I. |
title |
Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments |
title_short |
Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments |
title_full |
Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments |
title_fullStr |
Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments |
title_full_unstemmed |
Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments |
title_sort |
insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments |
publishDate |
2016 |
url |
https://hdl.handle.net/1983/803df102-633f-4818-8d60-7a4ffecc423c https://research-information.bris.ac.uk/en/publications/803df102-633f-4818-8d60-7a4ffecc423c https://doi.org/10.1016/j.chemgeo.2016.03.008 https://research-information.bris.ac.uk/ws/files/74379197/Stevenson_et_al_2016_finaledit.pdf http://www.sciencedirect.com/science/article/pii/S000925411630122X |
genre |
glacier Alaska Yukon |
genre_facet |
glacier Alaska Yukon |
op_source |
Stevenson , E I , Aciego , S M , Chutcharavan , P , Parkinson , I J , Burton , K W , Blakowski , M A & Arendt , C A 2016 , ' Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments ' , Chemical Geology , vol. 429 , pp. 33-43 . https://doi.org/10.1016/j.chemgeo.2016.03.008 |
op_relation |
https://research-information.bris.ac.uk/en/publications/803df102-633f-4818-8d60-7a4ffecc423c |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.chemgeo.2016.03.008 |
container_title |
Chemical Geology |
container_volume |
429 |
container_start_page |
33 |
op_container_end_page |
43 |
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1799480253163241472 |