What is it about?
The Patagonian ice sheet (PIS) was the largest ice sheet in the Southern Hemisphere besides Antarctica. Many studies have investigated the advances of the PIS on its eastern side, but there are only a few PIS records on the Pacific side. We use a marine sediment core to analyze the terrestrial input of the last 140,000 years, which gives us information about the activity of the western-central margin of the PIS. We show that three active intervals occurred during the last ~140 ka, with an extended PIS that contributed to the release of large amounts of freshwater and sediment into the Pacific.
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Photo by Hans-Jürgen Weinhardt on Unsplash
Why is it important?
Continental glaciers and ice sheets are excellent indicators of ongoing and past climate changes. The former PIS is at its western margin directly exposed to the Westerlies from the Pacific and therefore highly sensitive to changes in precipitation and temperature. In addition, our sampling site at the bifurcation of the South Pacific Current into the northward-flowing Peru-Chile Current and the southward-flowing Cape Horn Current is in an ideal position to gain unique insights into the ocean-atmosphere-ice interactions in this region during the last glacial.
Perspectives
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. Furthermore, this study shows that the choice of location is ideal to reconstruct a continuous record of western-central PIS activity much further back than the last glacial, which would allow us to examine the sensitivity of the region on long orbital timescales.
Julia Rieke Hagemann
Alfred Wegener Institute
Read the Original
This page is a summary of: A marine record of Patagonian ice sheet changes over the past 140,000 years, Proceedings of the National Academy of Sciences, March 2024, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2302983121.
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