Salinization of permafrost terrain due to natural geomorphic disturbance, Fosheim Peninsula, Ellesmere Island

Efflorescences (surface salt accumulations) are common on the Fosheim Penin sula and elsewhere in the Canadian Arctic Archipelago, especially at elevat ions below the Holocene marine limit, and cover up to 9% of the terrain in the vicinity of lower Hot Weather Creek. They are most extensive on natural ly disturbed slopes and in floodplain locations. More than 75% of effloresc ences are related to geomorphic disturbances (active-layer detachment slidi ng, retrogressive thaw slumping, and gullying), which initiate the causal c hain of (1) surface erosion; (2) local degradation of permafrost; (3) conta ct between supra-permafrost groundwater and soluble ions previously held wi thin frozen sediments; (4) increase in total dissolved-solids concentration s in slope surface runoff; and (5) depending on the degree of channelizatio n of drainage and the slope profile, transport of dissolved solids directly to the stream system or their redistribution and accumulation downslope. C oncentrations of Na+ in surface runoff reached almost 5 g l(-1) during summ er 1996 at a recent (1988) detachment slide scar in marine sediments. These concentrations are sufficiently high to negatively affect most terrestrial arctic plant species. Soluble Na+ levels within the active layer suggest t hat concentrations in slope runoff will remain elevated for several decades . Climatic warming, if it causes an increase in annual thaw depths or in th e frequency and extent of geomorphic disturbances, could also result in act ive layer salinization within areas of salt-rich permafrost, such as in mar ine surficial deposits.