Schwab, Christian; Kinkel, Hanno; Weinelt, M; Repschläger, Janne (2012): (Table S1) Age determination of sediment cores of the Azores Current System [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.824858, Supplement to: Schwab, C et al. (2012): Coccolithophore paleoproductivity and ecology response to deglacial and Holocene changes in the Azores Current System. Paleoceanography, 27(3), PA3210, https://doi.org/10.1029/2012PA002281
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Abstract:
In order to test the sensitivity of marine primary productivity in the midlatitude open ocean North Atlantic to changes in the Atlantic Meridional Overturning Circulation (AMOC), we investigated two spliced sediment cores from a site south of the Azores Islands at the northern rim of the North Atlantic subtropical gyre. For this purpose we analyzed coccolithophore assemblages, diatom abundances, alkenones and conducted X-ray fluorescence (XRF) core scanning. During times of reduced AMOC, especially during Heinrich event 1 (H1) and the Younger Dryas, we observe a strong increase in productivity as evidenced by high coccolith accumulation rates, high alkenone concentrations/accumulation rates, high Ba/Ti-ratios, high abundances of diatoms and low abundances ofF. profunda. The increased productivity is partly caused by a more southern position of the Azores Front (AzF), and hence by a less northward extension of the subtropical gyre, as deduced from high abundances of the temperate coccolithophore species G. muellerae and low abundances of subtropical species (Oolithotus spp., Umbellosphaera spp., Umbilicosphaeraspp.). However, to explain the full range of the observed productivity increase, other factors like increased westerly winds and advection of nutrient-rich surface waters have also to be considered. Because this pattern can also be observed in other sediment cores from the midlatitude North Atlantic, we propose that during times of reduced AMOC there has been a band of strongly increased productivity across the North Atlantic at the northern rim of the contracted subtropical gyre, which partly counteracts the decreased organic carbon pump in the high northern latitudes.
Coverage:
Median Latitude: 37.999415 * Median Longitude: -31.131415 * South-bound Latitude: 37.999000 * West-bound Longitude: -31.134500 * North-bound Latitude: 37.999830 * East-bound Longitude: -31.128330
Date/Time Start: 1993-08-01T00:00:00 * Date/Time End: 1993-08-01T00:00:00
Minimum DEPTH, sediment/rock: 0.0550 m * Maximum DEPTH, sediment/rock: 4.3000 m
Event(s):
KF16 * Latitude: 37.999000 * Longitude: -31.128330 * Date/Time: 1993-08-01T00:00:00 * Elevation: -3050.0 m * Campaign: GEOFAR * Basis: Le Noroit * Method/Device: Piston corer (PC)
MD08-3180 * Latitude: 37.999830 * Longitude: -31.134500 * Elevation: -3064.0 m * Recovery: 10.5 m * Location: Azores * Campaign: MD168 (AMOCINT, IMAGES XVII) * Basis: Marion Dufresne (1995) * Method/Device: Calypso Corer (CALYPSO)
Comment:
AMS determination on monospecific planktonic foraminifera (Globigerinoides runber white or Globigerina bulloides).
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Event label | Event | ||||
| 2 | DEPTH, sediment/rock | Depth sed | m | Geocode | ||
| 3 | Age, dated | Age dated | ka | Schwab, Christian | Age, 14C AMS | |
| 4 | Age, dated standard deviation | Age dated std dev | ± | Schwab, Christian | Age, 14C AMS | |
| 5 | Age, dated | Age dated | ka | Schwab, Christian | Age, 14C calibrated, CALIB 6.0 and Marine09 (Reimer et al., 2009) | |
| 6 | Reservoir effect/correction | Res effect | a | Schwab, Christian | ||
| 7 | Age model | Age model | ka | Schwab, Christian | tuned age BP |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
66 data points