One million years of glaciation and denudation history in west Greenland

• Published in: Nature Communications
• Main Authors: Strunk, Astrid, Knudsen, Mads Faurschou, Egholm, David Lundbek, Jansen, John, Levy, Laura, Jacobsen, Bo Holm, Larsen, Nicolaj Krog
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Greenland Ice Sheet; Erosion; cosmogenic nuclide; Quaternary climate; Greenland; Ice Sheet
• Online Access: https://pure.au.dk/portal/da/publications/one-million-years-of-glaciation-and-denudation-history-in-west-greenland(3880ad52-5348-4a25-ba94-2df6bff2681c).html; https://doi.org/10.1038/ncomms14199

The influence of major Quaternary climatic changes on growth and decay of the Greenland Ice Sheet, and associated erosional impact on the landscapes, is virtually unknown beyond the last deglaciation. Here we quantify exposure and denudation histories in west Greenland by applying a novel Markov-Chain Monte Carlo modelling approach to all available paired cosmogenic 10Be-26Al bedrock data from Greenland. We find that long-term denudation rates in west Greenland range from >50 m Myr−1 in low-lying areas to ∼2 m Myr−1 at high elevations, hereby quantifying systematic variations in denudation rate among different glacial landforms caused by variations in ice thickness across the landscape. We furthermore show that the present day ice-free areas only were ice covered ca. 45% of the past 1 million years, and even less at high-elevation sites, implying that the Greenland Ice Sheet for much of the time was of similar size or even smaller than today.