Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean
The ln(Zr/Rb) count ratio derived from X-ray fluorescence (XRF) core scanning holds potential as a high-resolution tracer for grain-size variations of glaciomarine sediments. To evaluate this approach, we conducted high-resolution grain-size measurements, together with Rb and Zr measurements by XRF...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:10113286 2023-12-24T10:25:03+01:00 Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean Wu, L Wilson, D Wang, R Yin, X Chen, Z Xiao, W Huang, M Krijgsman, W 2020-08-07 text https://discovery.ucl.ac.uk/id/eprint/10113286/1/Wu%20et%20al%202020%20ESSOAr.pdf https://discovery.ucl.ac.uk/id/eprint/10113286/ eng eng Earth and Space Science Open Archive (ESSOAr) https://discovery.ucl.ac.uk/id/eprint/10113286/1/Wu%20et%20al%202020%20ESSOAr.pdf https://discovery.ucl.ac.uk/id/eprint/10113286/ open Earth and Space Science Open Archive (ESSOAr): Washington, D.C., USA. (2020) Working / discussion paper 2020 ftucl 2023-11-27T13:07:27Z The ln(Zr/Rb) count ratio derived from X-ray fluorescence (XRF) core scanning holds potential as a high-resolution tracer for grain-size variations of glaciomarine sediments. To evaluate this approach, we conducted high-resolution grain-size measurements, together with Rb and Zr measurements by XRF core scanning and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), on a series of sediment cores from different regions of the Southern Ocean. We find that downcore changes of the ln(Zr/Rb) count ratio from XRF core scanning are consistent with Zr/Rb concentration ratios derived from ICP-MS analyses, even though Rb and Zr counts deviate significantly from concentrations due to specimen and matrix effects. The ln(Zr/Rb) count ratio displays discrepancies with the bulk mean grain-size, but correlates well with the mean grain-size of the sediment fractions that do not include unsorted coarse IRD (i.e. IRD-corrected mean grain-size). These observations are supported by evidence from a grain-size separation experiment, which indicates that Zr and Rb are concentrated in different grain-size fractions. Consistent with its lack of sensitivity to coarse grain-size fractions, the ln(Zr/Rb) ratio records similar trends to the sortable silt percent (SS%) and sortable silt mean (SSM) grain-size. Universal gradients exist in plots of ln(Zr/Rb) versus SS% (34.1), and ln(Zr/Rb) versus SSM (12.7), such that the ln(Zr/Rb) ratio provides a convenient way to estimate the magnitude of changes in SS% and SSM. Overall, our results support the use of the ln(Zr/Rb) ratio as an indicator of bottom current strength in cases where the sediment is current-sorted. Report Southern Ocean University College London: UCL Discovery Southern Ocean |
institution |
Open Polar |
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University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
description |
The ln(Zr/Rb) count ratio derived from X-ray fluorescence (XRF) core scanning holds potential as a high-resolution tracer for grain-size variations of glaciomarine sediments. To evaluate this approach, we conducted high-resolution grain-size measurements, together with Rb and Zr measurements by XRF core scanning and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), on a series of sediment cores from different regions of the Southern Ocean. We find that downcore changes of the ln(Zr/Rb) count ratio from XRF core scanning are consistent with Zr/Rb concentration ratios derived from ICP-MS analyses, even though Rb and Zr counts deviate significantly from concentrations due to specimen and matrix effects. The ln(Zr/Rb) count ratio displays discrepancies with the bulk mean grain-size, but correlates well with the mean grain-size of the sediment fractions that do not include unsorted coarse IRD (i.e. IRD-corrected mean grain-size). These observations are supported by evidence from a grain-size separation experiment, which indicates that Zr and Rb are concentrated in different grain-size fractions. Consistent with its lack of sensitivity to coarse grain-size fractions, the ln(Zr/Rb) ratio records similar trends to the sortable silt percent (SS%) and sortable silt mean (SSM) grain-size. Universal gradients exist in plots of ln(Zr/Rb) versus SS% (34.1), and ln(Zr/Rb) versus SSM (12.7), such that the ln(Zr/Rb) ratio provides a convenient way to estimate the magnitude of changes in SS% and SSM. Overall, our results support the use of the ln(Zr/Rb) ratio as an indicator of bottom current strength in cases where the sediment is current-sorted. |
format |
Report |
author |
Wu, L Wilson, D Wang, R Yin, X Chen, Z Xiao, W Huang, M Krijgsman, W |
spellingShingle |
Wu, L Wilson, D Wang, R Yin, X Chen, Z Xiao, W Huang, M Krijgsman, W Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean |
author_facet |
Wu, L Wilson, D Wang, R Yin, X Chen, Z Xiao, W Huang, M Krijgsman, W |
author_sort |
Wu, L |
title |
Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean |
title_short |
Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean |
title_full |
Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean |
title_fullStr |
Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean |
title_full_unstemmed |
Evaluating Zr/Rb ratios from XRF scanning as an indicator of grain-size variations of glaciomarine sediments in the Southern Ocean |
title_sort |
evaluating zr/rb ratios from xrf scanning as an indicator of grain-size variations of glaciomarine sediments in the southern ocean |
publisher |
Earth and Space Science Open Archive (ESSOAr) |
publishDate |
2020 |
url |
https://discovery.ucl.ac.uk/id/eprint/10113286/1/Wu%20et%20al%202020%20ESSOAr.pdf https://discovery.ucl.ac.uk/id/eprint/10113286/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Earth and Space Science Open Archive (ESSOAr): Washington, D.C., USA. (2020) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/10113286/1/Wu%20et%20al%202020%20ESSOAr.pdf https://discovery.ucl.ac.uk/id/eprint/10113286/ |
op_rights |
open |
_version_ |
1786200435376259072 |