Conclusion

Periglacial landforms and processes modify the glacial landscape of Disko Island. As Disko Island is located at the southern limit of the continuous permafrost zone, a future climate warming will cause imbalance in permafrost thickness and distribution and lead to increase in the rates of degradation processes. Increase in annual precipitation and glacier ice melt will enhance the total weathering rates, especially if the number of freeze-thaw cycles is significantly increased.

As the review of periglacial research on Disko Island shows, there is still limited knowledge on many aspects of how periglacial landforms evolve and how periglacial processes work in different environments. There is a lack of systematic mapping of the incidence of most periglacial landforms, which potentially can provide important information on climatic, topographic, hydrological sedimentological and vegetational controls. The decadal and centennial evolution of previously described landforms such as rock glaciers can contribute with information on climate-related fluctuations in process dynamics. If such information becomes available it will make geomorphological reconstructions of the landscape evolution possible, which can improve our knowledge on the late-Holocene history of the region. Also, more information on the geothermal regime is vital to our understanding of the sensitivity of permafrost thaw processes.

Probably the most challenging and contributing perspectives lie in the studies on the association between glaciers and permafrost. Here, Disko Island can provide optimal field conditions for studies on the formation and evolution of periglacial landforms on previously glaciated terrain. Glacier surge events reset the overridden landscape, and as the glaciers retreat rapid formation of landforms such as pingos and patterned ground may occur. There is a lot of evidence of buried glacier ice, which now can be classified as massive ground ice (permafrost), both of recent and Early Holocene age. In Kuannersuit Kuussuat (Kuannersuit Valley), an outwash plain with a sediment thickness of approximately 1 m developed on top of detached glacier ice during the recession of the Sorte Hak glaciers after a major surge event. Subsequently, several circular thaw lakes (thermokarst lakes) formed on the outwash plain. This indicates that a continuum ranging from down-wasting and back-wasting processes to periglacial thermokarst processes controls the deglaciation of formerly ice-covered landscapes, and shows how closely related glacial and periglacial processes are.

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