Sea surface temperatures reconstructed from alkenones of surface sediment samples of the Argentine Basin at stations GeoB1501-1 to GeoB2830-1, supplement to: Benthien, Albert; Müller, Peter J (2000): Anomalously low alkenone temperatures caused by lateral particle and sediment transport in the Malvinas Current region, western Argentine Basin. Deep Sea Research Part I: Oceanographic Research Papers, 47(12), 2369-2393

• Main Authors: Benthien, Albert, Müller, Peter J
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2000
• Subjects: Event label; Latitude of event; Longitude of event; Elevation of event; DEPTH, sediment/rock; Depth, top/min; Depth, bottom/max; Alkenone, unsaturation index UK'37; Sea surface temperature, annual mean; Δδ18O; Giant box corer; MultiCorer; Calculated from C37 alkenones Prahl & Wakeham, 1987; Calculated from UK'37 Müller et al, 1998; Calculated; M16/2; M23/1; M23/2; M23/3; M29/1; M29/2; Meteor 1986; Geosciences, University of Bremen GeoB; Argentine; NADW; North Atlantic Deep Water; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.66447; https://doi.pangaea.de/10.1594/PANGAEA.66447

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.