Ground ice in the upper permafrost of the Beaufort Sea coast of Alaska

Ground ice in the upper permafrost of the Beaufort Sea coast of Alaska was studied from 2005 to 2008 at 65 field sites located between Point Barrow and the Canadian border. The main terrain units in the studied area include (1) the primary surface of the coastal plain; (2) drained-lake basins; (3) low foothills (yedoma); (4) deltas and tidal flats; and (5) sand dunes. Wedge ice is the main type of massive ground ice, and ice-wedge polygons occurred on nearly all land surfaces. The volumetric content of wedge ice for the area varies from 3% to 50% between various terrain units with average value of about 11% for the entire coast. The highest content of wedge ice (about 50%) is typical of yedoma terrain, which occurred in a small segment at the coast of the Camden Bay. At the primary surface of the western region of the Arctic Coastal Plain, wedge-ice content reached almost 30%, with an average value of about 14%. Slightly smaller values were estimated for the primary surface of the eastern region of the Arctic Coastal Plain and for old drained-lake basins. Other types of massive ground ice included thermokarst-cave ice, ice cores of pingos, and a rare occurrence of folded massive ice at Barter Island. The content of segregated ice in organic and mineral soils between ice wedges was very high at most of the study sites. The total average volumetric ice content (due to wedge, segregated, and pore ice) for the whole area was 77%, ranging from 43% in eolian sand to 89% in yedoma. (C) 2012 Elsevier B.V. All rights reserved.