CGRG Bibliography of Canadian Geomorphology
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Author : Fishback, L.E.
Date : 2002.
Title : Establishing the provenance of catchment-derived pond sediments: Truelove Lowland, Devon Island (Northwest Territories).
Publication : Unpublished PhD dissertation. University of Western Ontario, London.
Issue :
Page(s) : 342 p.
Abstract
Ponds are more common than lakes in the high arctic landscape and until recently have been ignored as sources of paleoenvironmental information. The sediments from Pooh Pond and adjacent Fish Lake on Truelove Lowland are examined using a variety of physical, chemical and mineralogical techniques to assess the feasibility of using arctic pond sediments as a record of environmental processes. Fish Lake is a large, 7 m deep and ultra-oligotrophic freshwater lake that contains a sediment record of the post-glacial emergence of the lake analyzed from a 1.92 m core. The sediments of Pooh Pond, a large, 1.2 m deep, freshwater pond are characterized with four short sediment cores (<40cm). Chemical fractionation and selective extractions are used to characterize pond sediments and differentiate between materials from the catchment and the water body. A 14C sediment basal date of 5,980 ± 40 yrs BP (Beta-162840) from 32 cm depth was comparable to the predicted emergence date, indicating a freshwater origin of sediments collected. Significant differences between the four cores indicate the impact of local sedimentary environments within the pond. Examination of the biogeochemical characteristics of the sediment and associated current processes in the pond indicate that organic carbon is autochthonous and Fe, Al and Mn are originating in the catchment soils. Profile morphologies reflecting the pedogenic and cryogenic processes were found within a catena of four Cryosols on the intervening raised beach. Soils on the raised beach crest were poorly developed with pervection. Brunification dominates the upper and lower foreslope soils, while translocation of Fe and Al are indicative of localized podzolization. Soils at the slope base are waterlogged with accumulated organic matter over a gleyed silty parent material with high concentrations of Mn and Fe. A series of discriminant function analyses using reference sets comprising biogeochemical variables from the lake core and the catchment soils are used to identify the provenance of the pond sediments. It was concluded that the pond sediments were freshwater and predominantly allochthonous in origin. Modification during transport and deposition obscures the catchment signal and therefore influences interpretation of the autochthonous and allochthonous sediment record.
Bibliography of Canadian Geomorphology