Citation:

S0967-0637(00)00030-3

Name: Sea surface temperatures reconstructed from alkenones of surface sediment samples of the Argentine Basin at stations GeoB1501-1 to GeoB2830-1
Published: 2000
License: https://creativecommons.org/licenses/by/3.0/

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Published: 2000 (exact date unknown) • DOI registered: 2005-04-01

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Abstract:

We analysed the alkenone unsaturation ratio (UK'37) in 87 surface sediment samples from the western South Atlantic (5°N–50°S) in order to evaluate its applicability as a paleotemperature tool for this part of the ocean. The measured UK'37 ratios were converted into temperature using the global core-top calibration of Müller et al. (1998, doi:10.1016/S0016-7037(98)00097-0) and compared with annual mean atlas sea-surface temperatures (SSTs) of overlying surface waters. The results reveal a close correspondence (<1.5°C) between atlas and alkenone temperatures for the Western Tropical Atlantic and the Brazil Current region north of 32°S, but deviating low alkenone temperatures by -2° to -6°C are found in the regions of the Brazil–Malvinas Confluence (35–39°S) and the Malvinas Current (41–48°S). From the oceanographic evidence these low UK'37 values cannot be explained by preferential alkenone production below the mixed layer or during the cold season. Higher nutrient availability and algal growth rates are also unlikely causes. Instead, our results imply that lateral displacement of suspended particles and sediments, caused by strong surface and bottom currents, benthic storms, and downslope processes is responsible for the deviating UK'37 temperatures. In this way, particles and sediments carrying a cold water UK'37 signal of coastal or southern origin are transported northward and offshore into areas with warmer surface waters. In the northern Argentine Basin the depth between displaced and unaffected sediments appears to coincide with the boundary between the northward flowing Lower Circumpolar Deep Water (LCDW) and the southward flowing North Atlantic Deep Water (NADW) at about 4000 m.

Project(s):

Geosciences, University of Bremen (GeoB)

Coverage:

Median Latitude: -28.886647 * Median Longitude: -45.304923 * South-bound Latitude: -48.911667 * West-bound Longitude: -60.093333 * North-bound Latitude: 5.138333 * East-bound Longitude: -20.908333

Date/Time Start: 1991-04-30T00:00:00 * Date/Time End: 1994-08-06T00:00:00

Minimum DEPTH, sediment/rock: 0.005 m * Maximum DEPTH, sediment/rock: 0.020 m

Event(s):

GeoB1501-1 * Latitude: -3.681660 * Longitude: -32.011667 * Date/Time: 1991-04-30T00:00:00 * Elevation: -4258.0 m * Recovery: 0.45 m * Location: Brazil Basin * Campaign: * Basis: * Method/Device: Giant box corer (GKG) * Comment: Foram.-Sd., hellgrau-braun, halbfest;

GeoB1503-2 * Latitude: 2.310000 * Longitude: -30.648333 * Date/Time: 1991-05-02T00:00:00 * Elevation: -2298.0 m * Recovery: 0.37 m * Location: Brazil Basin * Campaign: * Basis: * Method/Device: Giant box corer (GKG) * Comment: Foram.-Sd., grau-braun, Pterop.-Schill

GeoB1504-1 * Latitude: 2.288333 * Longitude: -31.286670 * Date/Time: 1991-05-03T00:00:00 * Elevation: -2980.0 m * Recovery: 0.37 m * Location: Brazil Basin * Campaign: * Basis: * Method/Device: Giant box corer (GKG) * Comment: S, sandig, dunkelgrau; Pterop.-Schil

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	Event label	Event
2	Latitude of event	Latitude
3	Longitude of event	Longitude
4	Elevation of event	Elevation	m
5	DEPTH, sediment/rock	Depth sed	m			Geocode
6	Depth, top/min	Depth top	m	Benthien, Albert
7	Depth, bottom/max	Depth bot	m	Benthien, Albert
8	Alkenone, unsaturation index UK'37	UK'37		Benthien, Albert	Calculated from C37 alkenones (Prahl & Wakeham, 1987)
9	Sea surface temperature, annual mean	SST (1-12)	°C	Benthien, Albert	Calculated from UK'37 (Müller et al, 1998)
10	Δδ18O	Δδ18O	‰	Benthien, Albert	Calculated

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

481 data points

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Datasets with similar metadata

Schneider, RR; Müller, PJ; Ruhland, G (1995): Sea surface temperatures derived from alkenones from Late Quaternary sediments of the East Equatorial South Atlantic. https://doi.org/10.1594/PANGAEA.726545
Müller, PJ; Kirst, G; Ruhland, G et al. (1998): Alkenones and SST of surface sediments (Appendix). https://doi.org/10.1594/PANGAEA.54788
Benthien, A; Andersen, N; Schulte, S et al. (2002): Delta 13C measured on alkenones of surface sediment samples GeoB1008-6 to GeoB3603-1 from the South Atlantic. https://doi.org/10.1594/PANGAEA.63632