Classification and Relief Characteristics of Northern Alaska's Coastal Zone

Abstract

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 erosioncoast shaped primarily by marine agencies and exposed to the open ocean, being marked by coastal retreat and negligible nearshore deposition (37.5 per cent); Marine depositionsimilar 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 reliefless than about 2 m.; Moderafe reliefabout 2-5 m.; High reliefabout 5-8 m.; Very high reliefgreater than about 8 m. About 1,590 km. or 74 per cent 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 gzneral mean scarp heights decrease to the east along the coastal plain.

Soil carbon and material fluxes across the eroding Alaska Beaufort Sea coastline

“…The properties are extremely heterogeneous along the coastline and have been poorly quantified. Hartwell [1973] differentiated the coastline of northern Alaska as mostly fronted by barriers islands (34%) or eroding shoreline (37.5%), while deltaic accretion represents nearly 20% of the total coastline. Jorgenson and Brown [2005] refined the coastal classification on the basis of the compilation of previous studies and interpretation of Landsat imagery.…”

Sediment Transport Processes and Coastal Variability on the Alaskan North Slope

“…On the Chukchi shorelines 44.3% of the relief is greater than 5 m, whereas, on the Beaufort Sea coast only 11.3% of the relief is greater than 5 m (Hartwell, 1973). The primary effect of this regional variation in relief is that the drainage is predominantly towards the northeast.…”

“…In terms of broad characteristics, the Chukchi Sea has a coast of relatively high relief and straight shorelines with no large river systems or deltas. The more irregular coast of the Beaufort Sea is a result of (i) shoreline erosion in this area of thaw lakes and low relief, and (ii) possible contemporary submergence (Hartwell, 1973). The Beaufort Sea coast has many sections of low cliffs, barrier islands, thaw lakes, and numerous large deltas.…”

Polar Coasts

“…General descriptions of Arctic coastal geology and morphol ogy are provided by Hartwell (1973), Wiseman et al (1973), Walker (1985, Jorgenson and Brown (2005), and Walker and McGraw (2010) for Alaska; by Bird (1967Bird ( , 1985, Taylor and McCann (1983), Shaw et al (1998), andPollard (2010) for Arctic Canada; by Nielsen (1985) for Greenland; and by Zenkovich (1985), Drozdov et al (2005), Selivanov (2003 for the Russian Arctic. More recently, as a product of the Arctic Coastal Dynamics Project , a circumpolar coastal classification has been completed in GIS format (restricted to coasts directly fronting the Arctic Ocean; GIS, geographic information system), enabling a synth esis of coastal geology and geomorphology, including ice content and estimates of sediment and carbon delivery to the Arctic basin from coastal erosion (Rachold et al, 2003a(Rachold et al, , 2003bLantuit et al, 2008bLantuit et al, , 2009.…”