We investigate long-term SST variability of the western tropical South Atlantic (WTSA) using a 300 kyr-long SST record derived from Mg/Ca ratios in shells of Globigerinoides ruber (white). The foraminifera shells were derived from sediment core GL-1180, which was retrieved from 1037 m water depth at the northeastern continental margin of Brazil (8° 27'18 S, 33° 32'53 W) by the Brazilian oil company Petrobras. Measurements of Mg/Ca ratios were performed using an inductively coupled plasma optical emission spectrometer (ICP-OES) at MARUM-Center for Marine Environmental Sciences, University of Bremen. Additionally, Fe, Mn, and Al were measured to monitor contaminants.