Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’
Fine grain-size parameters have been used for inference of palaeoflow speeds of near-bottom currents in the deep-sea. The basic idea stems from observations of varying sediment size parameters on a continental margin with a gradient from slower flow speeds at shallower depths to faster at deeper. In...
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Online Access: | https://discovery.ucl.ac.uk/id/eprint/1565284/1/McCave%20et%20al.,%20Accepted%20MS%20DSR%20I.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/6/Appendix%201.%20Supplementary%20Material.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/14/Appendix%202.%20Calculated%20SS%20means%20for%20given%20inputs%20and%20flow%20speeds.xlsx https://discovery.ucl.ac.uk/id/eprint/1565284/ |
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ftucl:oai:eprints.ucl.ac.uk.OAI2:1565284 2023-12-24T10:18:00+01:00 Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’ McCave, IN Thornalley, DJR Hall, IR 2017-07-11 text spreadsheet https://discovery.ucl.ac.uk/id/eprint/1565284/1/McCave%20et%20al.,%20Accepted%20MS%20DSR%20I.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/6/Appendix%201.%20Supplementary%20Material.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/14/Appendix%202.%20Calculated%20SS%20means%20for%20given%20inputs%20and%20flow%20speeds.xlsx https://discovery.ucl.ac.uk/id/eprint/1565284/ eng eng https://discovery.ucl.ac.uk/id/eprint/1565284/1/McCave%20et%20al.,%20Accepted%20MS%20DSR%20I.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/6/Appendix%201.%20Supplementary%20Material.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/14/Appendix%202.%20Calculated%20SS%20means%20for%20given%20inputs%20and%20flow%20speeds.xlsx https://discovery.ucl.ac.uk/id/eprint/1565284/ open Deep Sea Research Part I: Oceanographic Research Papers (2017) Sortable silt current calibration mud current-meter sediment deposi Article 2017 ftucl 2023-11-27T13:07:35Z Fine grain-size parameters have been used for inference of palaeoflow speeds of near-bottom currents in the deep-sea. The basic idea stems from observations of varying sediment size parameters on a continental margin with a gradient from slower flow speeds at shallower depths to faster at deeper. In the deep-sea, size-sorting occurs during deposition after benthic storm resuspension events. At flow speeds below 10-15 cm s-1 mean grain-size in the terrigenous non-cohesive ‘sortable silt’ range (denoted by SS, mean of 10-63 μm) is controlled by selective deposition, whereas above that range removal of finer material by winnowing is also argued to play a role. A calibration of the SS grain-size flow speed proxy based on sediment samples taken adjacent to sites of long-term current meters set within ~100 m of the sea bed for more than a year is presented here. Grain-size has been measured by either Sedigraph or Coulter Counter, in some cases both, between which there is an excellent correlation for SS (r = 0.96). Size-speed data indicate calibration relationships with an overall sensitivity of 1.36 ± 0.19 cm s-1 /μm. A calibration line comprising 12 points including 9 from the Iceland overflow region is well defined, but at least two other smaller groups (Weddell/Scotia Sea and NW Atlantic continental rise/Rockall Trough) are fitted by subparallel lines with a smaller constant. This suggests a possible influence of the calibre of material supplied to the site of deposition (not the initial source supply) which, if depleted in very coarse silt (31-63 μm), would limit SS to smaller values for a given speed than with a broader size-spectrum 2 supply. Local calibrations, or a core-top grain-size and local flow speed, are thus necessary to infer absolute speeds from grain-size. The trend of the calibrations diverges markedly from the slope of experimental critical erosion and deposition flow speeds versus grain-size, making it unlikely that the SS (or any deposit size for that matter) is simply predicted by the ... Article in Journal/Newspaper Iceland Scotia Sea University College London: UCL Discovery Coulter ENVELOPE(-58.033,-58.033,-83.283,-83.283) Rockall Trough ENVELOPE(-15.036,-15.036,53.825,53.825) Scotia Sea Weddell |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Sortable silt current calibration mud current-meter sediment deposi |
spellingShingle |
Sortable silt current calibration mud current-meter sediment deposi McCave, IN Thornalley, DJR Hall, IR Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’ |
topic_facet |
Sortable silt current calibration mud current-meter sediment deposi |
description |
Fine grain-size parameters have been used for inference of palaeoflow speeds of near-bottom currents in the deep-sea. The basic idea stems from observations of varying sediment size parameters on a continental margin with a gradient from slower flow speeds at shallower depths to faster at deeper. In the deep-sea, size-sorting occurs during deposition after benthic storm resuspension events. At flow speeds below 10-15 cm s-1 mean grain-size in the terrigenous non-cohesive ‘sortable silt’ range (denoted by SS, mean of 10-63 μm) is controlled by selective deposition, whereas above that range removal of finer material by winnowing is also argued to play a role. A calibration of the SS grain-size flow speed proxy based on sediment samples taken adjacent to sites of long-term current meters set within ~100 m of the sea bed for more than a year is presented here. Grain-size has been measured by either Sedigraph or Coulter Counter, in some cases both, between which there is an excellent correlation for SS (r = 0.96). Size-speed data indicate calibration relationships with an overall sensitivity of 1.36 ± 0.19 cm s-1 /μm. A calibration line comprising 12 points including 9 from the Iceland overflow region is well defined, but at least two other smaller groups (Weddell/Scotia Sea and NW Atlantic continental rise/Rockall Trough) are fitted by subparallel lines with a smaller constant. This suggests a possible influence of the calibre of material supplied to the site of deposition (not the initial source supply) which, if depleted in very coarse silt (31-63 μm), would limit SS to smaller values for a given speed than with a broader size-spectrum 2 supply. Local calibrations, or a core-top grain-size and local flow speed, are thus necessary to infer absolute speeds from grain-size. The trend of the calibrations diverges markedly from the slope of experimental critical erosion and deposition flow speeds versus grain-size, making it unlikely that the SS (or any deposit size for that matter) is simply predicted by the ... |
format |
Article in Journal/Newspaper |
author |
McCave, IN Thornalley, DJR Hall, IR |
author_facet |
McCave, IN Thornalley, DJR Hall, IR |
author_sort |
McCave, IN |
title |
Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’ |
title_short |
Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’ |
title_full |
Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’ |
title_fullStr |
Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’ |
title_full_unstemmed |
Relation of sortable silt grain-size to deep-sea current speeds: Calibration of the ‘Mud Current Meter’ |
title_sort |
relation of sortable silt grain-size to deep-sea current speeds: calibration of the ‘mud current meter’ |
publishDate |
2017 |
url |
https://discovery.ucl.ac.uk/id/eprint/1565284/1/McCave%20et%20al.,%20Accepted%20MS%20DSR%20I.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/6/Appendix%201.%20Supplementary%20Material.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/14/Appendix%202.%20Calculated%20SS%20means%20for%20given%20inputs%20and%20flow%20speeds.xlsx https://discovery.ucl.ac.uk/id/eprint/1565284/ |
long_lat |
ENVELOPE(-58.033,-58.033,-83.283,-83.283) ENVELOPE(-15.036,-15.036,53.825,53.825) |
geographic |
Coulter Rockall Trough Scotia Sea Weddell |
geographic_facet |
Coulter Rockall Trough Scotia Sea Weddell |
genre |
Iceland Scotia Sea |
genre_facet |
Iceland Scotia Sea |
op_source |
Deep Sea Research Part I: Oceanographic Research Papers (2017) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/1565284/1/McCave%20et%20al.,%20Accepted%20MS%20DSR%20I.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/6/Appendix%201.%20Supplementary%20Material.pdf https://discovery.ucl.ac.uk/id/eprint/1565284/14/Appendix%202.%20Calculated%20SS%20means%20for%20given%20inputs%20and%20flow%20speeds.xlsx https://discovery.ucl.ac.uk/id/eprint/1565284/ |
op_rights |
open |
_version_ |
1786206493965549568 |