Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica
The (234U/238U) ratio in surface waters is generally higher than secular equilibrium due to nuclide recoil during alpha-decay of 238U. The size of the deviation from secular equilibrium contains information about the environment in which the water is found. This potential tool for environmental reco...
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Format: | Article in Journal/Newspaper |
Language: | English |
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2016
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Online Access: | https://doi.org/10.1016/j.chemgeo.2005.09.026 https://ora.ox.ac.uk/objects/uuid:ed17f5ad-e76c-42e0-b81d-d1c9ea5dae24 |
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ftuloxford:oai:ora.ox.ac.uk:uuid:ed17f5ad-e76c-42e0-b81d-d1c9ea5dae24 2023-05-15T13:37:40+02:00 Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica Henderson, G Hall, B Smith, A Robinson, L 2016-07-29 https://doi.org/10.1016/j.chemgeo.2005.09.026 https://ora.ox.ac.uk/objects/uuid:ed17f5ad-e76c-42e0-b81d-d1c9ea5dae24 eng eng doi:10.1016/j.chemgeo.2005.09.026 https://ora.ox.ac.uk/objects/uuid:ed17f5ad-e76c-42e0-b81d-d1c9ea5dae24 https://doi.org/10.1016/j.chemgeo.2005.09.026 info:eu-repo/semantics/embargoedAccess Journal article 2016 ftuloxford https://doi.org/10.1016/j.chemgeo.2005.09.026 2022-06-28T20:27:18Z The (234U/238U) ratio in surface waters is generally higher than secular equilibrium due to nuclide recoil during alpha-decay of 238U. The size of the deviation from secular equilibrium contains information about the environment in which the water is found. This potential tool for environmental reconstruction has previously been studied in rivers, groundwater, and sediment pore-water. Here we conduct a first assessment of the controls on (234U/ 238U) in lakewaters. Thirty-three waters from glacial melt, streams, and lakes of the McMurdo Dry Valleys (Antarctica) were analysed for U concentration and isotope ratio. Glacial melt has a low U concentration and a (234U/238U) identical to seawater, suggesting that U in Antarctic ice is largely sourced from sea-salt aerosols. Stream waters have higher U concentration (0.009 to 1.282 ppb) and (234U/238U) (1.280 to 1.832) due to chemical weathering of sediment in stream channels and 234U recoil from this sediment. Average (234U/238U) is 1.502, close to the average of observations from other surface waters worldwide. The absence of groundwaters in the Dry Valleys indicates that reasonably high (234U/238U) ratios do not require groundwater sources of U, so care should be taken before using high (234U/238U) as an indicator of groundwater inputs to stream waters. Lakewaters have U concentrations ranging from 0.027 to 46 ppb (i.e. up to 14 times the seawater concentration) and (234U/238U) from 1.05 to 4.50. Young lakes have (234U/238U) which reflects the sources of U. In one case (Lake Joyce) a (234U/238U) lower than seawater may suggest U sourced from melting of old ice in which 234U excess has partially decayed. In older lakes, (234U/238U) is significantly higher than that in the inputs due to addition of recoil 234U from sediments underlying the lake. The size of the deviation from secular equilibrium can only be explained, however, if recoil from a large area of sediment is considered. This is reasonable for the two lakes with particularly high (234U/238U) (Bonney, Vanda) ... Article in Journal/Newspaper Antarc* Antarctic Antarctica McMurdo Dry Valleys ORA - Oxford University Research Archive Antarctic McMurdo Dry Valleys Vanda ENVELOPE(161.550,161.550,-77.533,-77.533) Bonney ENVELOPE(162.417,162.417,-77.717,-77.717) Lake Joyce ENVELOPE(168.200,168.200,-77.467,-77.467) Chemical Geology 226 3-4 298 308 |
institution |
Open Polar |
collection |
ORA - Oxford University Research Archive |
op_collection_id |
ftuloxford |
language |
English |
description |
The (234U/238U) ratio in surface waters is generally higher than secular equilibrium due to nuclide recoil during alpha-decay of 238U. The size of the deviation from secular equilibrium contains information about the environment in which the water is found. This potential tool for environmental reconstruction has previously been studied in rivers, groundwater, and sediment pore-water. Here we conduct a first assessment of the controls on (234U/ 238U) in lakewaters. Thirty-three waters from glacial melt, streams, and lakes of the McMurdo Dry Valleys (Antarctica) were analysed for U concentration and isotope ratio. Glacial melt has a low U concentration and a (234U/238U) identical to seawater, suggesting that U in Antarctic ice is largely sourced from sea-salt aerosols. Stream waters have higher U concentration (0.009 to 1.282 ppb) and (234U/238U) (1.280 to 1.832) due to chemical weathering of sediment in stream channels and 234U recoil from this sediment. Average (234U/238U) is 1.502, close to the average of observations from other surface waters worldwide. The absence of groundwaters in the Dry Valleys indicates that reasonably high (234U/238U) ratios do not require groundwater sources of U, so care should be taken before using high (234U/238U) as an indicator of groundwater inputs to stream waters. Lakewaters have U concentrations ranging from 0.027 to 46 ppb (i.e. up to 14 times the seawater concentration) and (234U/238U) from 1.05 to 4.50. Young lakes have (234U/238U) which reflects the sources of U. In one case (Lake Joyce) a (234U/238U) lower than seawater may suggest U sourced from melting of old ice in which 234U excess has partially decayed. In older lakes, (234U/238U) is significantly higher than that in the inputs due to addition of recoil 234U from sediments underlying the lake. The size of the deviation from secular equilibrium can only be explained, however, if recoil from a large area of sediment is considered. This is reasonable for the two lakes with particularly high (234U/238U) (Bonney, Vanda) ... |
format |
Article in Journal/Newspaper |
author |
Henderson, G Hall, B Smith, A Robinson, L |
spellingShingle |
Henderson, G Hall, B Smith, A Robinson, L Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica |
author_facet |
Henderson, G Hall, B Smith, A Robinson, L |
author_sort |
Henderson, G |
title |
Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica |
title_short |
Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica |
title_full |
Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica |
title_fullStr |
Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica |
title_full_unstemmed |
Control on (U-234/U-238) in lake water: A study in the Dry Valleys of Antarctica |
title_sort |
control on (u-234/u-238) in lake water: a study in the dry valleys of antarctica |
publishDate |
2016 |
url |
https://doi.org/10.1016/j.chemgeo.2005.09.026 https://ora.ox.ac.uk/objects/uuid:ed17f5ad-e76c-42e0-b81d-d1c9ea5dae24 |
long_lat |
ENVELOPE(161.550,161.550,-77.533,-77.533) ENVELOPE(162.417,162.417,-77.717,-77.717) ENVELOPE(168.200,168.200,-77.467,-77.467) |
geographic |
Antarctic McMurdo Dry Valleys Vanda Bonney Lake Joyce |
geographic_facet |
Antarctic McMurdo Dry Valleys Vanda Bonney Lake Joyce |
genre |
Antarc* Antarctic Antarctica McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctic Antarctica McMurdo Dry Valleys |
op_relation |
doi:10.1016/j.chemgeo.2005.09.026 https://ora.ox.ac.uk/objects/uuid:ed17f5ad-e76c-42e0-b81d-d1c9ea5dae24 https://doi.org/10.1016/j.chemgeo.2005.09.026 |
op_rights |
info:eu-repo/semantics/embargoedAccess |
op_doi |
https://doi.org/10.1016/j.chemgeo.2005.09.026 |
container_title |
Chemical Geology |
container_volume |
226 |
container_issue |
3-4 |
container_start_page |
298 |
op_container_end_page |
308 |
_version_ |
1766095726190788608 |