Waelbroeck, Claire; Pichat, Sylvain; Böhm, Evelyn; Missiaen, Lise (2018): Sedimentary protactinium / thorium and opal in sediment core MD09-3257 from Western Equatorial Atlantic [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.894684, Supplement to: Waelbroeck, Claire; Pichat, Sylvain; Böhm, Evelyn; Lougheed, Bryan C; Faranda, Davide; Vrac, Mathieu; Missiaen, Lise; Vázquez Riveiros, Natalia; Burckel, Pierre; Lippold, Jörg; Arz, Helge Wolfgang; Dokken, Trond; Thil, François; Dapoigny, Arnaud (2018): Relative timing of precipitation and ocean circulation changes in the western equatorial Atlantic over the last 45 kyr. Climate of the Past, 14(9), 1315-1330, https://doi.org/10.5194/cp-14-1315-2018
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Abstract:
Thanks to its optimal location on the northern Brazilian margin, core MD09-3257 records both ocean circulation and atmospheric changes. The latter occur locally in the form of increased rainfall on the adjacent continent during the cold intervals recorded in Greenland ice and northern North Atlantic sediment cores (i.e. Greenland stadials). These rainfall events are recorded in MD09-3257 as peaks in ln(Ti/Ca). New sedimentary Pa/Th data indicate that mid-depth western equatorial water mass transport decreased during all of the Greenland stadials of the last 40 kyr. Using cross-wavelet transforms and spectrogram analysis, we assess the relative phase between the MD09-3257 sedimentary Pa/Th and ln(Ti/Ca) signals. We show that decreased water mass transport between a dept of ~1300 and 2300 m in the western equatorial Atlantic preceded increased rainfall over the adjacent continent by 120 to 400 y at Dansgaard-Oeschger (D-O) frequencies, and by 280 to 980 y at Heinrich-like frequencies.
We suggest that the large lead of ocean circulation changes with respect to changes in tropical South American precipitation at Heinrich-like frequencies is related to the effect of a positive feedback involving iceberg discharges in the North Atlantic. In contrast, the absence of widespread ice rafted detrital layers in North Atlantic cores during D-O stadials supports the hypothesis that a feedback such as this was not triggered in the case of D-O stadials, with circulation slowdowns and subsequent changes remaining more limited during D-O stadials than Heinrich stadials.
Coverage:
Median Latitude: -4.277083 * Median Longitude: -36.377083 * South-bound Latitude: -4.300000 * West-bound Longitude: -36.400000 * North-bound Latitude: -4.245000 * East-bound Longitude: -36.345000
Date/Time Start: 1996-03-30T00:00:00 * Date/Time End: 1996-03-30T00:00:00
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Size:
6 datasets
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Datasets listed in this publication series
- Waelbroeck, C; Pichat, S; Böhm, E et al. (2018): Age determination of sediment core GeoB3910-2. https://doi.org/10.1594/PANGAEA.894678
- Waelbroeck, C; Pichat, S; Böhm, E et al. (2018): Age model of sediment core GeoB3910-2. https://doi.org/10.1594/PANGAEA.894680
- Waelbroeck, C; Pichat, S; Böhm, E et al. (2018): Age determination of sediment core MD09-3257. https://doi.org/10.1594/PANGAEA.894679
- Waelbroeck, C; Pichat, S; Böhm, E et al. (2018): Age model of sediment core MD09-3257. https://doi.org/10.1594/PANGAEA.894681
- Waelbroeck, C; Pichat, S; Böhm, E et al. (2018): Protactinium, thorium and uranium activities and ratios in sediment cores MD09-3257 and GeoB3910-2. https://doi.org/10.1594/PANGAEA.894682
- Waelbroeck, C; Pichat, S; Böhm, E et al. (2018): Opal in sediment core MD09-3257. https://doi.org/10.1594/PANGAEA.894683