EVIDENCE OF SOIL FORMATION IN HIGH ARCTIC POND SEDIMENTS

Although most of the material in arctic lake and pond sediments is believed to be allochthonous, few attempts have been made to establish the provenance of this material. An investigation of soil conditions adjacent to a freshwater pond in the Truelove Lowland of Devon Island, Nunavut, Canada provided an opportunity to study the similarity between the products of soil formation and the pond sediment.

In the course of this study, samples were obtained from a soil catena formed on a raised beach adjacent to the pond. At the same time, four short (<0.4m) poorly stratified sediment cores were obtained from the pond. Both sample sets were analyzed for particle size, mineralogy, organic carbon, total carbonates, and total nitrogen. Fe, Al and Mn were extracted with sodium pyrophosphate, ammonium oxalate and dithionite-citrate-bicarbonate solutions; exchangeable Ca, Mg, K and autochthonous and allochthonous fractions obtained using established techniques; and macro, trace and rare earth element concentrations measured with INAA.

The soils range from Regosolic Static Cryosols on the beach crest, through Brunisolic Eutric Static Cryosols and Brunisolic Eutric Turbic Cryosols on the upper and lower foreslope respectively, to Gleysolic Turbic Cryosols in the sedge meadows adjacent to the pond. Pedogenic processes identified include decarbonation in the upper sola on the lower foreslope and carbonation in the lower sola resulting in carbonate pendants on the larger clasts; pervection of silt-sized particles; gleization resulting in significant Mn and Al mobilization in the meadow soils; organic matter accumulation, especially in the surface horizons of the meadow soils; and pedotranslocation of iron and aluminum in the better-drained foreslope soils.

Multivariate statistical analyses, including cluster analysis and discriminant function analysis, of the soil and sediment samples confirmed that the bulk of the pond sediment shares similar characteristics with the soil samples. However, it is clear also that the provenance of the pond sediment is complex and that it bears the imprint of numerous processes, both allochthonous and autochthonous in origin.