Sea surface temperature reconstructions over the last 70kyr off Portugal: Biomarker data and regional modeling - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Paleoceanography Année : 2016

Sea surface temperature reconstructions over the last 70kyr off Portugal: Biomarker data and regional modeling

Sophie Darfeuil
  • Fonction : Auteur
Xavier Giraud
Frauke Rostek
  • Fonction : Auteur
  • PersonId : 958279
Marta Garcia
Edouard Bard

Résumé

This study aims at providing robust temperature reconstructions for a key oceanographic setting in the North Atlantic and at understanding the nature of the temperature signal recorded by the two biomarkers U-37(k) and TEX86, considering season and depth of production. To do so, high-resolution signals of U-37(k) and TEX86 are determined for the last 70kyr for core MD95-2042, located off Portugal. Signals of U-37(k) and TEX86 present a tight correlation, demonstrating a dominant temperature effect. U-37(k) signals correspond well to the annual mean sea surface temperature (SST), whereas TEX86H-derived temperatures are 5.6 degrees C higher, which is unrealistically warm for this area. Unsuitable TEX86 global linear calibrations on the Iberian Margin may suggest a possible occurrence of archaeal communities with specific temperature response. To assess the impact of different season or depth of production of the biomarkers on the recorded temperature in the sediment, modeled temperature proxies (Tproxies) are introduced in a Regional Oceanic Modeling System and tested for different seasons (annual/summer/winter) and depths (surface and 0-200m) of production for three climate modes (Present Day (PD), Last Glacial Maximum (LGM), and Heinrich Stadials (HS)). Similar temperature amplitudes between climate modes are found at MD95-2042 core site for observations, for both biomarkers, and for modeled annual surface production Tproxy: 5.5-7 degrees C for T(PD-LGM) and 3-4 degrees C for T(LGM-HS). Therefore, we propose a new TEX86H regional calibration to reconstruct present and past annual mean SSTs on the Iberian Margin.
Fichier principal
Vignette du fichier
2015PA002831.pdf (2.13 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-01463313 , version 1 (09-09-2021)

Licence

Copyright (Tous droits réservés)

Identifiants

Citer

Sophie Darfeuil, Guillemette Menot, Xavier Giraud, Frauke Rostek, K. Tachikawa, et al.. Sea surface temperature reconstructions over the last 70kyr off Portugal: Biomarker data and regional modeling. Paleoceanography, 2016, 31 (1), pp.40-65. ⟨10.1002/2015PA002831⟩. ⟨hal-01463313⟩
152 Consultations
23 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More