Arctic coastal zone mapping: Evolution of sedimentary coasts in Greenland.
Mette Bendixen, PhD student, CENPERM/IGN
Arctic sedimentary coasts experience an increasing pressure due to the ongoing warming climate. Permafrost thaws and destabilizes the coast, ice-free periods on sea prolong and increase the period where waves can erode the coast, and sea-level rises due to increasing freshwater supply and thermal expansion. As a consequence, existing studies reveal severe erosion throughout large parts of the tundra-coasts in Alaska, Canada, and Russia in recent years. However, it remains unclear until now how sedimentary coasts in Greenland respond to a warming climate.
In this talk I will show sedimentary coastal evolution at Disko Island, Western Greenland. Shoreline changes since 1964 are estimated using aerial photos, orthophotos, and satellite images. Two hot-spots with large changes are detected around two deltas and the processes responsible for the large accretion and migration rates are discussed. Our results fill the knowledge gap there is regarding sedimentary coastal evolution in Greenland.
Moreover, I will introduce our work on beach-ridge plain evolution at Disko Island. In this work, I will examine the beach ridges in relation to their sources of sediments and there sea-levels. We date our beach ridge sediments with Optically Stimulated Luminescence (OSL) and try to quantify the processes that control the evolution of beach ridges in the Arctic. This will contribute to a better understanding of sea-level fluctuations in the Holocene.
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