Magnetic signals in deep-sea sediments have the potential to unravel past continental environmental changes – via changes in primary terrigenous magnetic supply – but also record past marine environmental conditions – via in situ formation of secondary magnetic minerals, particularly when complemented by independent proxies. This dataset provides rock magnetic, major element and grain size of siliciclastic data from marine sediment core GL-1090. This core is 1914 cm long and was collected from the continental slope (2225 m water depth) of southeastern South America (24.92°S, 42.51°W). We combined environmagnetic, geochemical, and siliciclastic grain size data aiming to unravel changes in terrigenous sediment input and bottom water conditions during the last ~184 ka at the western South Atlantic mid-depth.