ABSTRACT: Late Quaternary history and engineering geology of The Elk River Valley, Southeastern British Columbia

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

Stratigraphic evidence suggests that the Elk Valley was subject to at least two major glaciations during the Late Quaternary. Slope break evidence, on the other hand, is indicative of at least three (possibly four) major undated glaciations during the Quaternary. The major ice advances inferred from both stratigraphic and geomorphic evidence are termed, in order of increasing age; Elkford Advance, Greenhills Advance, Earlier Advance II, and Earlier Advance I. Retreat of Elkford Advance ice was for the most part accomplished by glacier recession there, being little evidence of stagnant ice conditions. Glacial lake deposits are more extensive than previously reported. Silty glaciolacustrine deposits noted in the upper reaches of the Elk Valley were either formed within a single lake (Glacial Lake I), or in poorly interconnected bodies of water occupying embayments between a shrinking valley glacier and the confining valley walls. Another lake, Glacial Lake Elk, occupied the entire Elk Valley to within 50 km of Elk Lakes. It drained in two major and one minor (the latter relatively short-lived) stages. These stages are 1384m at Crowsnest Pass (major stage), with present-day elevation of 1357m; 1204m along Bean Creek (minor stage); and 1036m via the Elko channel (major stage). Preconsolidation stresses, as determined by conventional oedometer tests on Glacial Lake Elk varved clays, are much greater than would be expected from geological considerations. High initial void ratios, liquidity indices and an environment favourable to the presence of calcium carbonate suggest that the varved clays are cemented. Consideration of failure stresses, failure strains, and the variation of Skempton's pore-pressure 'A' support this view. Examination of the inter-relationship between the plasticity characteristics of lodgement tills and the nature of the parent materials from which the tills were derived indicate that tills derived from predominantly fine-grained clastic bedrock formations are distinguishable from other units originating in terrain possessing less of a fine grained component, by their relative plot positioning on a plasticity chart. This fact opens possibilities for the use of a simple engineering basis for differentiating and predicting the engineering behaviour of till units during regional terrain analysis. In addition, it offers potential application in local till stratigraphic correlation studies.

Bibliography of Canadian Geomorphology