Oceanic forcing of patagonian ice sheet variability over the last eight glacial cycles

Abstract The Northern and Southern Patagonian Ice Fields are remnants of the much larger Patagonian Ice Sheet that existed during past glacial periods. Using a continuous marine sediment record on the southern Chilean margin, we reconstruct the Patagonian Ice Sheet waning and waxing over eight glacial cycles. The reconstructed ice-rafted debris and terrigenous biomarker inputs show advances in all glacial periods and largely covary with sea surface temperature changes in the Southeast Pacific suggesting persistent oceanic forcings on the ice-sheet´s mass balance between glacials and interglacials. Similarities between changes in ice sheet extent and dust input to the pelagic Southern Ocean reinforce the suggested role of the Patagonian Ice Sheet as a major producer of dust-sized particles. This freshly eroded Patagonian dust is thought to be fundamental in shaping glacial-interglacial climate variability through influencing the supply of bioavailable iron and thus marine productivity and carbon uptake.