Upwelling dominated oceanographic periods in the Ria de Vigo during the late Holocene

作者：Martins V^*; Araujo M F; Silva E F; Dias J M A; Calisto R; Jouanneau J M; Weber O; Rocha F

来源：Journal of Coastal Research, 2011, 1998-2001.

• Late Holocene
• climatic conditions
• NW Iberian Margin
• sedimentary dynamic
• paleoproductivity
• diagenesis

Martins, V., Araujo, M. F., Silva, E.F., Dias, J.M.A, Calisto, R., Jouanneau, J.-M., Weber, O. and Rocha, F., 2011. Upwelling dominated oceanographic periods in the Ria de Vigo during the late Holocene. Journal of Coastal Research, SI 64 (Proceedings of the 11th International Coastal Symposium), 1998 - 2001. Szczecin, Poland, ISSN 0749-0208.
Different oceanographic regimes were identified at millennial scale in the last 3 ka cal BP in a sedimentary sequence from the outer sector of Ria de Vigo (NW Spain) based on a multi-proxy approach (textural, mineralogical, geochemical and benthic foraminifera data). The prevalence of stronger wave climate linked with a developed downwelling regime and a more efficient erosion phase, allowed the deposition of coarser sediments, enriched in geogenic (Si/Al and Zr/Al) and biogenic chemical elements (Ca/Al and Sr/Al), coarse detrital minerals (quartz and feldspars) and carbonates during the periods approximate to 2.9-2.3 ka cal BP and approximate to 1.5-0.6 ka cal BP. However the prevalence of soother wave climate regime, linked with reinforced upwelling events, could have occurred between approximate to 2.5-1.5 ka cal BP and approximate to 0.5-0 ka cal BP, giving origin to a Finer sedimentation enriched in organic matter and phyllosilicates. In these muddy events the consumption of oxygen during aerobic organic matter degradation caused suboxic/anoxic conditions in the sediments, which induced higher early diagenetic changes with pyrite formation in anoxic environments. When the sediments became again oxic/suboxic precipitation of redox, sensitive elements such as Fe and Ni could have arisen.

• 出版日期2011