Chapter 12 The Impact of Glacial Geomorphology on Critical Zone Processes
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At the present time, most of the glaciers on Earth are located in Antarctica, ~98% of which is covered by ice with an average thickness of 1.6km. In the Arctic, Greenland has the principal ice sheet with an area of 1,755,637km2 and a thickness up to 3,200m. Individual valley glaciers, such as Vatnajkull, which is the largest glacier (~1000-m thick) in Iceland, are significant factors in the local environments.With such a large spatial extent and major role as a sink for fresh water, especially in light of the current focus on global change, the cryospheric subsystem plays a very important role as a part of the Critical Zone of Earth. This area does not quite fit the original definition of the Critical Zone as the vertical zone extends from the top of the vegetation canopy to the bottom of the aquifer. For glacier regions in alpine locations, the top of the canopy has to be understood as the top of trees or bushes, sages, shrubs or grasses growing on various glacial deposits. In Polar Regions the top of the canopy is assumed to include the lower portion of the stratosphere.The relationship of glacial erosional processes and landforms to former ice sheets determines the continuity of subglacial deformed layers, associated landforms and sediments. Glacial erosion generates landscape evolution and relief production and moreover, can be used to assess paleoenvironmental factors. People living within the regions impacted by glaciers, in the present or past, must adapt and adjust how they use the surface to live successfully in glaciated regions. The term Critical Zone is very appropriate for how humans respond to surficial changes wrought by glaciers. 2015 Elsevier B.V.