Missiaen, Lise; Pichat, Sylvain; Waelbroeck, Claire; Douville, Eric; Bordier, Louise; Dapoigny, Arnaud; Thil, François; Foliot, Lorna; Wacker, Lukas (2018): Downcore variations of sedimentary detrital (238U/232Th) ratio of sediment core SU90-08 [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.889695, Supplement to: Missiaen, L et al. (2018): Downcore Variations of Sedimentary Detrital (238U/232Th) Ratio: Implications on the Use of 230Thxs and 231Paxs to Reconstruct Sediment Flux and Ocean Circulation. Geochemistry, Geophysics, Geosystems, 19, https://doi.org/10.1029/2017GC007410
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Abstract:
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.
Coverage:
Latitude: 43.353333 * Longitude: -30.408333
Date/Time Start: 1990-01-01T00:00:00 * Date/Time End: 1990-01-01T00:00:00
Event(s):
SU90-08 * Latitude: 43.353333 * Longitude: -30.408333 * Date/Time: 1990-01-01T00:00:00 * Elevation: -3080.0 m * Recovery: 12.27 m * Location: North Atlantic * Campaign: PALEOCINAT * Basis: Le Suroît * Method/Device: Piston corer (PC)
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
6 datasets
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Datasets listed in this publication series
- Missiaen, L; Pichat, S; Waelbroeck, C et al. (2018): (Table S1) Age model of sediment core SU90-08. https://doi.org/10.1594/PANGAEA.889685
- Missiaen, L; Pichat, S; Waelbroeck, C et al. (2018): (Table S2) 238U and 232Th measurements in leaching residues in sediment core SU90-08. https://doi.org/10.1594/PANGAEA.889690
- Missiaen, L; Pichat, S; Waelbroeck, C et al. (2018): (Table S3) 238U and 232Th measurements in handpicked bulk IRDs in sediment core SU90-08. https://doi.org/10.1594/PANGAEA.889691
- Missiaen, L; Pichat, S; Waelbroeck, C et al. (2018): (Table S4) 238U and 232Th measurements in handpicked detrital carbonates in sediment core SU90-08. https://doi.org/10.1594/PANGAEA.889692
- Missiaen, L; Pichat, S; Waelbroeck, C et al. (2018): (Table S5) 238U and 232Th measurements in residues remaining after acid dissolution of handpicked detrital carbonates in sediment core SU90-08. https://doi.org/10.1594/PANGAEA.889693
- Missiaen, L; Pichat, S; Waelbroeck, C et al. (2018): (Table S6) 238U, 232Th and 230Th activities measured in bulk samples in sediment core SU90-08. https://doi.org/10.1594/PANGAEA.889694