Sea surface temperature changes in the western South Atlantic and precipitation variability in southeastern South America since the Last Glacial Maximum

Abstract

Southeastern South America (SESA) is the most densely populated and agriculturally productive region of the continent, greatly relying on South American summer monsoon (SASM) precipitation. A comprehensive understanding of the SASM activity on different time scales is thus a key issue. Here we propose to reconstruct sea surface and thermocline temperatures in the subtropical western South Atlantic since the Last Glacial Maximum in order to check if key periods of changes in precipitation over SESA (e.g., Heinrich Stadial 1, Bølling-Allerød, Younger Dryas, mid Holocene) were related to sea surface temperature changes in the subtropical western South Atlantic and to the latitudinal migration of the Brazil-Malvinas Confluence. Therefore, Mg/Ca and stable oxygen isotopes in selected species of planktonic foraminifera from three carefully selected marine sediment cores from the subtropical western South Atlantic will be analyzed. The sediment cores will have age models determined based on 14C AMS datings on monospecific foraminifera. Additionally, bulk sediment geochemistry will be analyzed on all cores in order to refine the variability in continental precipitation. Through this project we expect to significantly contribute to the debate of possible impacts of future climate change in SESA. (AU)