2025/07/28 by Anne Søndergaard, Anja Rosenberg, Mads Faurschou Knudsen +6 · 1 voice
Earth and Planetary Sciences · Environmental Science · #Cryospheric studies and observations #Geology and Paleoclimatology Research #Methane Hydrates and Related Phenomena
paper · pdf · doi:10.1111/bor.70029
openalex created_date 2025/07/28 · openalex publication_date 2025/07/28 · openalex updated_date 2026/08/01
Knowledge of the glacial history of the North Greenland Ice Sheet is crucial due to its high sensitivity to climate change. However, because the ice sheet in this region is predominantly cold‐based, resulting in low erosion rates, using 10 Be exposure dating to establish reliable ice sheet chronologies has proven very challenging due to nuclide inheritance. In this study, we measure 16 rock samples for their in situ 14 C concentration, most of which already showed 10 Be nuclide inheritance, resulting in apparent exposure ages pre‐dating the most recent deglaciation. We combine our new results with seven already published in situ 14 C exposure ages to build a North Greenland‐wide in situ 14 C ice sheet chronology based on a total of 20 boulder and three bedrock samples. Resulting in situ 14 C ages range from 4.8 to 22.4 ka, and more than half of our in situ 14 C exposure ages show signs of excess nuclides, pre‐dating the most recent deglaciation at individual sample sites. We believe the excess nuclides could be a result of limited erosion during the Last Glacial Maximum (LGM) and a combination of pre‐LGM exposure, supraglacial pre‐deposition exposure and possibly thin ice cover. Our new large‐scale in situ 14 C data set contributes important knowledge on the glacial history of North Greenland and ice‐bed properties in this region. Despite challenges, all in situ 14 C exposure ages except two are younger than their 10 Be counterpart, which highlights the potential and necessity of in situ 14 C exposure dating in regions with cold‐based ice and low erosion rates.