A note on a thermokarst feature on the North Slope of Alaska

Abstract

A thermokarst depression with active thermal erosion on one margin and a drainage way to the Sagavanirktok River is described with the aid of a sketch plan and sections. The depression is surrounded by moist tundra with thermal contraction polygons and floored by wet tundra with extensive pools. It is drained by a partly sinuous flat-floored shallow valley with gentle margins. Three radiocarbon dates from a section of organic sediment at the margin of the depression, exposed by erosion, show that its accumulation extends back at least 7410 radiocarbon years. A pollen spectrum from the organic sediment at 5240a BP indicates the presence of moist tundra heath with dwarf shrubs. The feature is briefly discussed in relation to Pleistocene relict thermokarst.

Keywords

• thermokarst
• organic residues
• pollen analysis
• absolute age
• C-13
• Holocene
• Alaska