Quartäre Schwankungen in Strömungsintensität und Produktivität als Abbild der Wassermassen-Variabilität im äquatorialen Atlantik (ODP Sites 959 und 663): Ergebnisse aus Siltkorn-Analysen.

Abstract

In order to reconstruct intermediate water circulation of the equatorial Atlantic and paleoproductivity of the equatorial divergence, silt grain-size analysis were performed on sediments of the north-westem African continental slope (ODP Site 959) and on pelagic sediments of the Guinea Basin (ODP Site 663) for the last 1 Ma.Silt grain-size records of ODP Site 959 monitor distinct fluctuations of the intermediate water circulation of the equatorial Atlantic especially during tenninations. Based on the terrigenous "sortable silt" fraction, grain-size spectra of the terrigenous silt and their statistic grain-size parameters, variations of the UNADW/GNAIW circulation could be deduced due to glacial/interglacial changes. The observed gradients should have been strengthened by the exposed setting of ODP Site 959. During the period from 1 Ma - today a low but continous sedimentation was detennined at Site 959.