Paraglacial coastal systems uncovered from retreating glaciers - organisational controls and typologies of the youngest coasts in the Northern Hemisphere

Since the end of the Little Ice Age thousands of kilometers of new coastlines have been uncovered by retreating glaciers across the Northern Hemisphere. This new terrain begun to function as the youngest coastal environments on Earth. As  glaciers retreat, they leave a mixture of landforms including moraines, eskers, crevasse squeeze ridges, glaciofluvial deposits or glacially polished bedrock ready for the  transformation by waves,  tides and currents. In extreme cases, the newly exposed coastline takes form of entire islands.  Although this process is one of the fastest geomorphological metamorphosis of cold region landscape  we have only limited understanding of its rates and complexity. Here, we present the results of remote sensing and geomorphological investigations of the mechanisms controlling the formation of new coastal landforms using examples from rapidly deglaciating sites in Svalbard and Greenland.  We focus on two previously unexplored topics in cold region coastal geomorphological research– the formation of paraglacial lagoons, build from moraines left onshore by marine-terminating glaciers and the impact of tsunami-like waves triggered by rockfalls or glacier calving on Arctic beach morphodynamics. In addition, we address the research challenges that are anticipated to emerge in the future, including the resilience of juvenile coasts to storm impacts and the role of newly exposed coastal areas in the development of coastal permafrost and the emergence of geoecological oases. 

  

This is a contribution to National Science Centre projects: 'ASPIRE–Arctic storm impacts recorded in beach-ridges and lake archives: scenarios for less icy future’ No. UMO– 2020/37/B/ST10/03074 and  ‘GLAVE– paraglacial coasts transformed by tsunami waves – past, present and warmer future’ No. UMO– 2020/38/E/ST10/00042.