Reconstruction of hydrographic properties at the sea surface in the Brazilian equatorial margin during the holocene

Abstract

Reconstruction of environmental variables such as temperature and ocean salinity of past times is important for an understanding of the natural variability of global climate. The purpose of the present project is to reconstruct the temperature and salinity of the sea surface in the Brazilian equatorial continental margin during the Holocene, from Mg/Ca ratio and oxygen isotope data (´18O) in planktonic foraminiferal tests. We are working with a core (GeoB-16204-2) collected in offshore Parnaíba river (latitude 01°59.75' S, longitude 42°20.30' W, 1210 m water depth). The chronology of the GeoB-16204-2 was established based on radiocarbon datings using AMS 14C of tests Globigerinoides ruber. Furthermore, grains size and X-ray fluorescence (XRF) data are available. Speciments of Globigerinoides ruber white will be pick up for Mg/Ca and d18O analyses in University of Bremen. To learn this technique is required a three-month training period, which will be accomplished in collaboration with the researchers of the Geosciences Department at the University of Bremen. After this period we will be able to estimate sea surface temperature, to estimate sea surface salinity and describe hydrographic sea surface changes. The results will be analyzed as graphical representations, and statistical methods may also able to be used to investigate the possible links between variations in the surface paleo-ocean and terrigenous input changes. (AU)