Abstract

In formerly glaciated permafrost regions, extensive areas are still underlain by a considerable amount of glacier ice buried by glacigenic sediments. Although the extent and volume of undisturbed relict glacier ice are unknown, these ice bodies are predicted to melt with climate warming but their impact on landscape evolution remains poorly studied. The spatial distribution of buried glacier ice can play a significant role in reshaping periglacial landscapes, in particular thermokarst aquatic systems. This study focuses on lake initiation and development in response to the melting of buried glacier ice on Bylot Island, Nunavut. We studied a lake-rich area using lake-sediment cores, detailed bathymetric data, remotely sensed data and observations of buried glacier ice exposures. Our results suggest that initiation of deeper thermokarst lakes was triggered by the melting of buried glacier ice. They have subsequently enlarged through thermal and mechanical shoreline erosion, as well as vertically through thaw consolidation and subsidence, and they later coalesced with neighbouring water bodies to form larger lakes. Thus, these lakes now evolve as “classic” thermokarst lakes that expand in area and volume as a result of the melting of intrasedimental ground ice in the surrounding material and the underlying glaciofluvial and till material. It is expected that the deepening of thaw bulbs (taliks) and the enlargement of Arctic lakes in response to global warming will reach undisturbed buried glacier ice, if any, which in turn will substantially alter lake bathymetry, geochemistry and greenhouse gas emissions from Arctic lowlands.

Highlights

  • 30 Arctic landscapes underlain by ice-rich permafrost are highly vulnerable to climate change and permafrost degradation (Biskaborn et al, 2019; Cai et al, 2019; Lewkowicz and Way, 2019; AMAP, 2017)

  • The broad distribution and the 20 substantial amount of ground ice in permafrost-preserved glacial landscapes make it highly vulnerable to disturbances, such as thermokarst, under the ongoing climate warming. Some of these landscapes are experiencing climate-driven renewed deglaciation leading to post-glacial landscape evolution that transformed sub-Arctic environments millennia ago

  • The ice-free zones of Bylot Island are still strongly influenced by its glacial legacy given the presence of late Pleistocene-age glacier ice buried in the permafrost in Qarlikturvik Valley (Coulombe et al, 2019) and in other valleys and coastal plains of the island (Klassen, 1993; Moorman and Michel, 2000).These ice-cored landforms have been adjusting to non-glacial conditions and their evolution is strongly linked with climate, geomorphological processes and local topography

Read more

Summary

Introduction

30 Arctic landscapes underlain by ice-rich permafrost are highly vulnerable to climate change and permafrost degradation (Biskaborn et al, 2019; Cai et al, 2019; Lewkowicz and Way, 2019; AMAP, 2017). The broad distribution and the 20 substantial amount of ground ice in permafrost-preserved glacial landscapes make it highly vulnerable to disturbances, such as thermokarst, under the ongoing climate warming. Some of these landscapes are experiencing climate-driven renewed deglaciation leading to post-glacial landscape evolution that transformed sub-Arctic environments millennia ago. In flat or very gently 25 sloping terrain, formation and evolution of ponds and lakes are typically associated with the melting of intrasedimental ice, such as ice wedges and segregation ice (Bouchard et al, 2017; Grosse et al, 2013). There is little information on the spatial distribution and abundance and evolution in modern paraglacial and periglacial environments on these glacial thermokarst lakes (Jorgenson and Osterkamp, 2005)

Methods
Results
Discussion
Conclusion

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 call

Disclaimer: 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.