Classification and Relief Characteristics of Northern Alaska's Coastal Zone

  • Allan D. Hartwell
Keywords: Bottom sediments, Coast changes, Genetics, Geomorphology, Rivers, Sea level, Sediment transport, Alaska, Northern, Thompson, Cape, (68 08 N, 165 58 W)


Four main genetic coastal types are proposed to classify the shoreline of northern Alaska bordering the Chukchi and Beaufort Seas, which extends for more than 2,150 km. from Cape Thompson eastward to the Canadian border: Land erosion - coast marked by subaerial erosion of terrestrially shaped land forms and partly drowned by rise in sea level (8.9 per cent of coastline); River deposition - coast formed by fluvial deposition (19.9 per cent); Wave erosion - coast shaped primarily by marine agencies and expos to the open ocean, being marked by coastal retreat and negligible nearshore deposition (37.5 per cent); Marine deposition - similar to preceding except nearshore sediment deposition is pronounced (33.7 per cent). Four categories of coastal relief or sea cliff height associated with these coastal types are proposed: Low relief - less than about 2 m; Moderate relief - about 2-5 m; High relief - about 5-8 m; Very high relief - greater than about 8 m. About 1590 km or 74% of the coast has relief of 5 m or less whereas mean relief or scarp height for the entire coast is about 4 m. In general, mean scarp heights decrease to the east along the coastal plain.