CGRG Bibliography of Canadian Geomorphology
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Author : Bond, J.D.; and Sanborn, P.T.
Date : 2006.
Title : Morphology and geochemistry of soils formed on colluviated weathered bedrock: Case studies from unglaciated upland slopes in west-central Yukon.
Publication : Yukon Geological Survey, Whitehorse, Yukon.
Issue : Open File 2006-19.
Page(s) : 70 p.
Abstract
Soil morphology and geochemistry were studied at three mineral properties (gold; lead-zinc; copper-gold) in the unglaciated terrain of west-central Yukon. The purpose of this work was two-fold: to describe soil and parent material properties, and secondly, to assess the effects of soil development and slope processes on element distribution in soils derived primarily from colluvium and weathered bedrock. At each property, soils were examined on slopes with opposing aspects. Slopes with a north-facing aspect have poorly defined horizons due to cryoturbation. This process has also mixed most recent glacial loess into the upper soil horizons (0-50 cm depth), which can geochemically dilute the weathered bedrock parent material by as much as 600%. On south-facing slopes, the soils are permafrost-free and have more abrupt horizon boundaries. Geochemical variability within these soils is largely determined by colluvium composition rather than in-situ soil weathering. These results provide baseline pedological and soil-geomorphological descriptions for the Klondike Plateau, which will assist future biophysical mapping and contribute to our understanding of landscape evolution. Results pertaining to soil geochemistry provide landscape related guidelines for mineral exploration. For example, the stratigraphic distribution of loess within soil profiles is described according to slope aspect. This allows the explorationist to design sampling procedures that are more likely to detect geochemical anomalies in the underlying bedrock. Soil geochemical variations in colluvium are shown to reflect upslope variations in bedrock lithology. Results of the soil particle size fraction geochemistry indicate that for base metal elements such as copper, lead and zinc, the -80 mesh component was generally the most responsive in either the B or C horizon. For gold, the -80 mesh fraction worked well in the B horizon, whereas the -230 mesh contained the highest concentration in the C horizon.
Bibliography of Canadian Geomorphology