Past circulation along the western Iberian margin: a time slice vision from the Last Glacial to the Holocene

• Published in: Quaternary science reviews Vol. 106; pp. 316 - 329
• Main Authors: Salgueiro, E., Naughton, F., Voelker, A.H.L., de Abreu, L., Alberto, A., Rossignol, L., Duprat, J., Magalhães, V.H., Vaqueiro, S., Turon, J.-L., Abrantes, F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.12.2014
• Subjects: Heinrich stadial; Iberian margin; Last Glacial Maximum; Paleoproductivity; Paleotemperature; Planktonic foraminifera; Younger Dryas; Last Glacial Maximum; Planktonic foraminifera; Paleotemperature; Paleoproductivity; Iberian margin; Heinrich stadial; Younger Dryas
• ISSN: 0277-3791; 1873-457X
• DOI: 10.1016/j.quascirev.2014.09.001

Fifteen Iberian margin sediment cores, distributed between 43°12′N and 35°53′N, have been used to reconstruct spatial and temporal (sub)surface circulation along the Iberian margin since the Last Glacial period. Time-slice maps of planktonic foraminiferal derived summer sea surface temperature (SST) and export productivity (Pexp) were established for specific time intervals within the last 35 ky: the Holocene (Recent and last 8 ky), Younger Dryas (YD), Heinrich Stadials (HS) 1, 2a, 2b, 3, and the Last Glacial Maximum (LGM). The SST during the Holocene shows the same latitudinal gradient along the western Iberian margin as present-day with cold but productive areas that reflect the influence of coastal upwelling centers. The LGM appears as a slightly less warm, but more productive period relative to the Holocene and present-day conditions, suggesting that sea-level minima forced a westward displacement of the coastal upwelling centers possibly accompanied by a strengthening of northward winds. During the YD, a longitudinal thermal front is depicted at 10°W, with cold polar waters offshore and warmer subtropical waters inshore, suggesting that the subtropical Paleo-Iberian Poleward Current more likely flowed at a more inshore location masking the local SST signal and amplitude of variation. A substantial cooling and drop in productivity is observed during all HS, in particular HS1 and HS3, reflecting the penetration of icebergs-derived meltwater. These most extreme southward extensions of very cold waters define a strong SST gradient that marks a possible Paleo-Azores Front. Higher production south of this front was likely fed by frontal nutrient advection. [Display omitted] •SST and productivity time slice reconstructions for the Iberian margin.•Holocene SST and productivity patterns same as seen satellite data.•Last Glacial Maximum relative warm period but with enhanced productivity.•N–S extending tongue of cold SST along margin during all Heinrich stadials.•Productivity diminished within cold water tongue but enhanced south of the tongue.