Sediment core shows climate changes in the Patagonian ice sheet

“For the first time, our study presents a continuous marine record of the extent of the west-central Patagonian ice sheet over a complete glacial-interglacial cycle back to the penultimate glacial 140,000 years ago,” says Julia R. Hagemann from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). The study shows three active intervals with an extended ice sheet in western Patagonia, which contributed large amounts of freshwater and sediment into the Pacific. Two active intervals occurred during the last glacial about 70,000 to 60,000 and 40,000 to 18,000 years ago. These two intervals with an extended western ice sheet are characterized by altering phases of increased ice discharge, most likely caused by changes in precipitation.

Glaciers and ice fields are an important marker for the progression of climate change. The Patagonian ice sheet extended over several climate zones and its western flank was subject to the strongly fluctuating climatic influences of the last glacial. As the study shows, it released large quantities of material to the Pacific during high glacial phases due to changing precipitation and temperature conditions. “Our study shows very clearly how sensitively marine ice sheets react to changing climate conditions,” explains Julia R. Hagemann.

Original Publication:

Hagemann, J.R., Lamy, F., Arz, H.W., Lembke-Jene, L., Auderset, A., Harada, N., Ho, S.L., Iwasaki, S., Kaiser, J., Lange, C.B., Murayama, M., Nagashima, K., Nowaczyk, N., Martínez-García, A. and Tiedemann, R., 2024. A marine record of Patagonian ice sheet changes over the past 140,000 years. PNAS. DOI: 10.1073/pnas.2302983121