Dynamic ice-wallow relief of northern Alaska's nearshore.

Contour maps with 0.5m depth interval were prepared for a small area seaward of Reindeer Island, a barrier island in the Beaufort Sea, Alaska, by repeated surveys with very accurate navigation and very close trackline spacing. The maps reveal numerous closed depressions and mounds, presumably related to grounded ice floes common in the area year round. These bedforms represent erosion and deposition caused by: a) intensified flow around stationary ice floes serving as obstacles and b) pulsating currents generated by vertical oscillations or rocking motions of grounded floes in a seaway. Because sediment transport occurs around the ice, not where it directly touches the sea floor, the depressions are much larger than the base of the acting floes. Ice-wallow bedforms, are characteristic of arctic nearshore regions with non-cohesive sediments. The bedforms studied here are highly active and must be considered in planning nearshore construction activities. -from Authors