Source versus weathering processes as controls on the Mackenzie river uranium isotope signature
Uranium (U) isotope signatures (δ238U) recorded in sedimentary archives provide insight into the paleo redox state of the ocean. But the robust interpretation of these sedimentary U isotope records requires characterisation of the U isotope signature of rivers, the main source of U to the ocean. The...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/606143 2023-11-12T04:20:47+01:00 Source versus weathering processes as controls on the Mackenzie river uranium isotope signature Charbonnier, Quentin Clarkson, Matthew O. Hilton, Robert G. Vance, Derek 2023-05-20 application/application/pdf https://hdl.handle.net/20.500.11850/606143 https://doi.org/10.3929/ethz-b-000606143 en eng Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.chemgeo.2023.121409 info:eu-repo/semantics/altIdentifier/wos/000965107000001 info:eu-repo/grantAgreement/SNF/Projekte MINT/184873 http://hdl.handle.net/20.500.11850/606143 doi:10.3929/ethz-b-000606143 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Chemical Geology, 625 Weathering Mackenzie Basin Uranium stable isotopes info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2023 ftethz https://doi.org/20.500.11850/60614310.3929/ethz-b-00060614310.1016/j.chemgeo.2023.121409 2023-10-22T23:50:41Z Uranium (U) isotope signatures (δ238U) recorded in sedimentary archives provide insight into the paleo redox state of the ocean. But the robust interpretation of these sedimentary U isotope records requires characterisation of the U isotope signature of rivers, the main source of U to the ocean. The main controlling factors on riverine δ238U remain poorly constrained. Here, we investigate the elemental and isotope signatures of uranium in the dissolved and solid loads of a well-characterised river, the Mackenzie Basin (Canada). In the Mackenzie Basin, the solid load δ238U shows a positive relationship with U and vanadium (V) contents, consistent with the suggestion that particulate δ238U are explained by variable contributions via erosion of silicate and black shale. The δ238U of the dissolved and solid loads are correlated which, at first sight, suggests no U isotope fractionation during chemical weathering, and a purely lithological control on both the river dissolved and solid δ238U. Moreover, relationships between dissolved U and δ238U and major elements such as calcium and sulfate, also support the idea of a lithological control. However, the δ238U of end members inferred from mixing relationships are not consistent with binary mixing of two sources, suggesting some potential U isotope fractionation during weathering. In fact, the abundance of U in the river dissolved load is always lower than that predicted by silicate rock weathering. This suggests that 1) the weathering of silicate only can explain the abundance of U in the river dissolved load and 2) secondary weathering processes scavenge a proportion of the U released by primary mineral breakdown. The broad negative relationship between δ238U and the depletion of dissolved U is also consistent with the control of dissolved δ238U by secondary weathering processes following silicate mineral breakdown. The relationships observed between dissolved U, δ238U and the large-scale environmental controls on weathering processes (such as weathering intensity or ... Article in Journal/Newspaper Mackenzie Basin Mackenzie river ETH Zürich Research Collection Canada Mackenzie River |
institution |
Open Polar |
collection |
ETH Zürich Research Collection |
op_collection_id |
ftethz |
language |
English |
topic |
Weathering Mackenzie Basin Uranium stable isotopes |
spellingShingle |
Weathering Mackenzie Basin Uranium stable isotopes Charbonnier, Quentin Clarkson, Matthew O. Hilton, Robert G. Vance, Derek Source versus weathering processes as controls on the Mackenzie river uranium isotope signature |
topic_facet |
Weathering Mackenzie Basin Uranium stable isotopes |
description |
Uranium (U) isotope signatures (δ238U) recorded in sedimentary archives provide insight into the paleo redox state of the ocean. But the robust interpretation of these sedimentary U isotope records requires characterisation of the U isotope signature of rivers, the main source of U to the ocean. The main controlling factors on riverine δ238U remain poorly constrained. Here, we investigate the elemental and isotope signatures of uranium in the dissolved and solid loads of a well-characterised river, the Mackenzie Basin (Canada). In the Mackenzie Basin, the solid load δ238U shows a positive relationship with U and vanadium (V) contents, consistent with the suggestion that particulate δ238U are explained by variable contributions via erosion of silicate and black shale. The δ238U of the dissolved and solid loads are correlated which, at first sight, suggests no U isotope fractionation during chemical weathering, and a purely lithological control on both the river dissolved and solid δ238U. Moreover, relationships between dissolved U and δ238U and major elements such as calcium and sulfate, also support the idea of a lithological control. However, the δ238U of end members inferred from mixing relationships are not consistent with binary mixing of two sources, suggesting some potential U isotope fractionation during weathering. In fact, the abundance of U in the river dissolved load is always lower than that predicted by silicate rock weathering. This suggests that 1) the weathering of silicate only can explain the abundance of U in the river dissolved load and 2) secondary weathering processes scavenge a proportion of the U released by primary mineral breakdown. The broad negative relationship between δ238U and the depletion of dissolved U is also consistent with the control of dissolved δ238U by secondary weathering processes following silicate mineral breakdown. The relationships observed between dissolved U, δ238U and the large-scale environmental controls on weathering processes (such as weathering intensity or ... |
format |
Article in Journal/Newspaper |
author |
Charbonnier, Quentin Clarkson, Matthew O. Hilton, Robert G. Vance, Derek |
author_facet |
Charbonnier, Quentin Clarkson, Matthew O. Hilton, Robert G. Vance, Derek |
author_sort |
Charbonnier, Quentin |
title |
Source versus weathering processes as controls on the Mackenzie river uranium isotope signature |
title_short |
Source versus weathering processes as controls on the Mackenzie river uranium isotope signature |
title_full |
Source versus weathering processes as controls on the Mackenzie river uranium isotope signature |
title_fullStr |
Source versus weathering processes as controls on the Mackenzie river uranium isotope signature |
title_full_unstemmed |
Source versus weathering processes as controls on the Mackenzie river uranium isotope signature |
title_sort |
source versus weathering processes as controls on the mackenzie river uranium isotope signature |
publisher |
Elsevier |
publishDate |
2023 |
url |
https://hdl.handle.net/20.500.11850/606143 https://doi.org/10.3929/ethz-b-000606143 |
geographic |
Canada Mackenzie River |
geographic_facet |
Canada Mackenzie River |
genre |
Mackenzie Basin Mackenzie river |
genre_facet |
Mackenzie Basin Mackenzie river |
op_source |
Chemical Geology, 625 |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.chemgeo.2023.121409 info:eu-repo/semantics/altIdentifier/wos/000965107000001 info:eu-repo/grantAgreement/SNF/Projekte MINT/184873 http://hdl.handle.net/20.500.11850/606143 doi:10.3929/ethz-b-000606143 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International |
op_doi |
https://doi.org/20.500.11850/60614310.3929/ethz-b-00060614310.1016/j.chemgeo.2023.121409 |
_version_ |
1782336558211268608 |