Abstract: Sedimentological and geochemical results from samples in the Richardson Mountains indicate that siliceous shales and chert of the Canol Formation were deposited in stratified, oxygen-depleted waters that favoured the preservation of organic matter. Dilution by terrigenous input was minimal; however, fluctuating palaeoproductivity resulted in significant biogenic silica enrichment that reduced porosity. The Canol Formation was divided into four regionally correlatable chemostratigraphic zones. Each zone was characterized by up-section profiles of: decreasing biogenic silica enrichment, increasing proportions of siliceous shale relative to chert, decreasing redox-sensitive Mo, U and V enrichment factors and decreasing Mo/TOC (total organic carbon) ratios. A preliminary sequence stratigraphic framework was constructed and eustasy invoked as the dominant allogenic control. Mo/TOC ratios are indicative of a silled, restricted basin with euxinic deepwater. The overall decrease up-section of these ratios suggests increasing restriction over time, associated with relative sea-level fall. Comparison of north Yukon data with similar modern and ancient basins has constrained preliminary reconstructions of Canol basin palaeohydrography.

Authors: Hutchison, M.P. and Fraser, T.A.

Citation: Hutchison, M.P. and Fraser, T.A., 2015. Palaeoenvironment, palaeohydrography and chemostratigraphic zonation of the Canol Formation, Richardson Mountains, north Yukon. In: Yukon Exploration and Geology 2014, K.E. MacFarlane, M.G. Nordling and P.J. Sack (eds.), Yukon Geological Survey, p. 73-98.

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