Abstract
Abstract. Determining the sensitivity of the Greenland Ice Sheet (GrIS) to Holocene climate changes is a key prerequisite for understanding the future response of the ice sheet to global warming. In this study, we present new information on the Holocene glacial history of the GrIS in Inglefield Land, north Greenland. We use 10Be and in situ 14C exposure dating to constrain the timing of deglaciation in the area and radiocarbon dating of reworked molluscs and wood fragments to constrain when the ice sheet retreated behind its present-day extent. The 10Be ages are scattered ranging from ca. 92.7 to 6.8 ka, whereas the in situ 14C ages range from ca. 14.2 to 6.7 ka. Almost half of the apparent 10Be ages predate the Last Glacial Maximum and up to 89 % are to some degree affected by nuclide inheritance. Based on the few reliable 10Be ages, the in situ 14C ages and existing radiocarbon ages from Inglefield Land, we find that the deglaciation along the coast commenced at ca. 8.6–8.3 ka cal BP in the western part and ca. 7.9 ka in the central part, following the opening of Nares Strait and arrival of warm waters. The ice margin reached its present-day position at ca. 8.2 ka at the Humboldt Glacier and ca. 6.7 ka in the central part of Inglefield Land. Radiocarbon ages of reworked molluscs and wood fragments show that the ice margin was behind its present-day extent from ca. 5.8 to 0.5 ka cal BP. After 0.5 ka cal BP, the ice advanced towards its Little Ice Age position. Our results emphasize that the slowly eroding and possibly cold-based ice in north Greenland makes it difficult to constrain the deglaciation history based on 10Be ages alone unless they are paired with in situ 14C ages. Further, combining our findings with those of recently published studies reveals distinct differences between deglaciation patterns of northwest and north Greenland. Deglaciation of the land areas in northwest Greenland occurred earlier than in north Greenland, and periods of restricted ice extent were longer, spanning the Middle and Late Holocene. Overall, this highlights past ice sheet sensitivity to Holocene climate changes in an area where little information was available just a few years ago.
Highlights
Information about the glacial history of the Greenland Ice Sheet (GrIS) is important to constrain its sensitivity to past and ongoing climate changes (Lecavalier et al, 2017; Larsen et al, 2018)
Based on the few reliable 10Be ages, the in situ 14C ages and existing radiocarbon ages from Inglefield Land, we find that the deglaciation along the coast commenced at ca. 8.6–8.3 ka cal BP in the western part and ca. 7.9 ka in the central part, following the opening of Nares Strait and arrival of warm waters
Since the 1990s, mass loss from the GrIS has accelerated, coinciding with atmospheric warming, and the ice sheet appears to be extremely sensitive to this warming, especially in north Greenland, where the ablation area has expanded by 46 % (Khan et al, 2015; Noël et al, 2019)
Summary
Information about the glacial history of the Greenland Ice Sheet (GrIS) is important to constrain its sensitivity to past and ongoing climate changes (Lecavalier et al, 2017; Larsen et al, 2018). Since the 1990s, mass loss from the GrIS has accelerated, coinciding with atmospheric warming, and the ice sheet appears to be extremely sensitive to this warming, especially in north Greenland, where the ablation area has expanded by 46 % (Khan et al, 2015; Noël et al, 2019). The relative contribution to sea level rise from the north GrIS has increased significantly, primarily through enhanced runoff as well as ice discharge via calving and melting at the Humboldt Glacier front (Mouginot et al, 2019; Noël et al, 2019). Søndergaard et al.: Glacial history of Inglefield Land, north Greenland
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
