Downcore variations of sedimentary detrital (238U/232Th) ratio of sediment core SU90-08
Fuente:
PANGAEA
Saved in:
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Dataset Open Access |
| Language: | en |
| Published: |
PANGAEA
2018
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1867168571519401984 |
|---|---|
| author | Missiaen, Lise Pichat, Sylvain Waelbroeck, Claire Douville, Eric Bordier, Louise Dapoigny, Arnaud Thil, François Foliot, Lorna Wacker, Lukas |
| author_facet | Missiaen, Lise Pichat, Sylvain Waelbroeck, Claire Douville, Eric Bordier, Louise Dapoigny, Arnaud Thil, François Foliot, Lorna Wacker, Lukas |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Excess 231 Pa and 230 Th ( 231 Pa xs and 230 Th xs ) can be used to reconstruct past oceanic sedimentation ( 230 Th-normalized flux) and circulation changes (( 231 Pa/ 230 Th) xs,0 , hereafter Pa/Th). These quantities are determined by computing the detrital and authigenic contributions from bulk sediment measurement. The method relies on the use of a chosen constant value of the detrital ( 238 U/ 232 Th) activity ratio (hereafter (U/Th) det ). In this study, we have extracted the detrital fraction of the sediments from North Atlantic deep-sea core SU90-08 (43°03'1N, 30°02'5W, 3080m) and determined its (U/Th) det value over the last 40 ky. We find that (U/Th) det varied significantly through time with a minimum value of 0.4 during the Holocene and a maximum value of 0.7 during the Last Glacial Maximum (LGM). The sensitivity of sedimentary 230 Th-normalized flux and Pa/Th is tested for our study site and for other North-Atlantic sites. We show that the sensitivity is highly dependent on the core location and its terrigenous material supply. The 230 Th-normalized flux and Pa/Th signals are very robust in cores with low detrital contributions, whereas they are very sensitive to (U/Th) det changes in cores with higher detrital contribution. In the latter case, changes in 230 Th-normalized flux and Pa/Th due to the choice of a constant (U/Th) det can largely exceed the uncertainty on the 230 Th-normalized flux and Pa/Th, inducing potential biases in the amplitude and temporal variability of reconstructed sedimentation and ocean circulation changes. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_889695 |
| institution | PANGAEA |
| language | en |
| publishDate | 2018 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Downcore variations of sedimentary detrital (238U/232Th) ratio of sediment core SU90-08 Missiaen, Lise Pichat, Sylvain Waelbroeck, Claire Douville, Eric Bordier, Louise Dapoigny, Arnaud Thil, François Foliot, Lorna Wacker, Lukas Le Suroît; North Atlantic Ocean; PALEOCINAT; PC; Piston corer; SU90-08 Excess 231 Pa and 230 Th ( 231 Pa xs and 230 Th xs ) can be used to reconstruct past oceanic sedimentation ( 230 Th-normalized flux) and circulation changes (( 231 Pa/ 230 Th) xs,0 , hereafter Pa/Th). These quantities are determined by computing the detrital and authigenic contributions from bulk sediment measurement. The method relies on the use of a chosen constant value of the detrital ( 238 U/ 232 Th) activity ratio (hereafter (U/Th) det ). In this study, we have extracted the detrital fraction of the sediments from North Atlantic deep-sea core SU90-08 (43°03'1N, 30°02'5W, 3080m) and determined its (U/Th) det value over the last 40 ky. We find that (U/Th) det varied significantly through time with a minimum value of 0.4 during the Holocene and a maximum value of 0.7 during the Last Glacial Maximum (LGM). The sensitivity of sedimentary 230 Th-normalized flux and Pa/Th is tested for our study site and for other North-Atlantic sites. We show that the sensitivity is highly dependent on the core location and its terrigenous material supply. The 230 Th-normalized flux and Pa/Th signals are very robust in cores with low detrital contributions, whereas they are very sensitive to (U/Th) det changes in cores with higher detrital contribution. In the latter case, changes in 230 Th-normalized flux and Pa/Th due to the choice of a constant (U/Th) det can largely exceed the uncertainty on the 230 Th-normalized flux and Pa/Th, inducing potential biases in the amplitude and temporal variability of reconstructed sedimentation and ocean circulation changes. |
| title | Downcore variations of sedimentary detrital (238U/232Th) ratio of sediment core SU90-08 |
| topic | Le Suroît; North Atlantic Ocean; PALEOCINAT; PC; Piston corer; SU90-08 |
| url | https://doi.org/10.1594/PANGAEA.889695 |