A marine record of Patagonian ice sheet changes over the past 140,000 years

• 成果类型: Article
• 署名作者: Hagemann, Julia R.; Lamy, Frank; Arz, Helge W.; Lembke-Jene, Lester; Auderset, Alexandra; Harada, Naomi; Ho, Sze Ling; Iwasaki, Shinya; Kaiser, Jerome; Lange, Carina B.; Murayama, Masafumi; Nagashima, Kana; Nowaczyk, Norbert; Martinez-Garcia, Alfredo; Tiedemann, Ralf
• 署名单位: Helmholtz Association; Alfred Wegener Institute, Helmholtz Centre for Polar & Marine Research; Max Planck Society; University of Bremen; Leibniz Institut fur Ostseeforschung Warnemunde; University of Southampton; NERC National Oceanography Centre; University of Tokyo; Japan Agency for Marine-Earth Science & Technology (JAMSTEC); National Taiwan University; Hokkaido University; Universidad de Concepcion; Universidad de Concepcion; Universidad Austral de Chile; University of California System; University of California San Diego; Scripps Institution of Oceanography; Kochi University; Kochi University; Helmholtz Association; Helmholtz-Center Potsdam GFZ German Research Center for Geosciences
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9822
• DOI: 10.1073/pnas.2302983121
• 发表日期: 2024-03-19
• 关键词: sea-surface temperature; last glacial maximum; lago buenos-aires; climate variability; southeast pacific; bipolar seesaw; chronology; chile; ocean; sensitivity

摘要

Terrestrial glacial records from the Patagonian Andes and New Zealand Alps document quasi- synchronous Southern Hemisphere-wide glacier advances during the late Quaternary. However, these records are inherently incomplete. Here, we provide a continuous marine record of western-central Patagonian ice sheet (PIS) extent over a complete glacial-interglacial cycle back into the penultimate glacial (-140 ka). Sediment core MR16-09 PC03, located at 46 degrees S and -150 km offshore Chile, received high terrestrial sediment and meltwater input when the central PIS extended westward. We use biomarkers, foraminiferal oxygen isotopes, and major elemental data to reconstruct terrestrial sediment and freshwater input related to PIS variations. Our sediment record documents three intervals of general PIS marginal fluctuations, during Marine Isotope Stage (MIS) 6 (140 to 135 ka), MIS 4 (-70 to 60 ka), and late MIS 3 to MIS 2 (-40 to 18 ka). These higher terrigenous input intervals occurred during sea - level low stands, when the western PIS covered most of the Chilean fjords, which today retain glaciofluvial sediments. During these intervals, high- amplitude phases of enhanced sediment supply occur at millennial timescales, reflecting increased ice discharge most likely due to a growing PIS. We assign the late MIS 3 to MIS 2 phases and, by inference, older advances to Antarctic cold stages. We conclude that the increased sediment/meltwater release during Southern Hemisphere millennial - scale cold phases was likely related to higher precipitation caused by enhanced westerly winds at the northwestern margin of the PIS. Our records complement terrestrial archives and provide evidence for PIS climate sensitivity.