The bedrock geology of the Arctic is dominated by large areas of sedimentary, igneous and metamorphic rocks. Repeated glaciations and erosional processes reshaped the landscapes and deposited various thicknesses of surficial materials. During the glacial periods, large parts of the Canadian and Scandinavian Arctic were covered by glacial ice, which deposited variable thicknesses of glacial materials. Remnants of this ice still remain in Greenland, and as ice caps in the northeastern part of the Canadian Arctic. Coastal areas usually are associated with marine deposits, because of sea-level changes and glacial rebound.
A large part of the Arctic in Eurasia and northwestern North America (Alaska and part of Yukon) was unglaciated, and is covered with thick surficial materials of eolian (loess), colluvial and lacustrine origin. Most of the Siberian Arctic is associated with deep yedoma sediments derived from windblown, reworked colluvial materials.
Peat deposits are common surficial deposits, especially in the southern part of the Arctic. These deposits, which are usually about 2-3 m thick, result from peat deposition during the last 5,000-8,000 years. They usually occur in lowlands, and are associated with ice-wedge polygons. These peat deposits play an important role in the carbon budget of the area.
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