Differentiation of Glacial Tills in Southern Ontario, Canada, Based on Their Cu, Zn, Cr, and Ni Geochemistry
R. W. May, A. Dreimanis, 1973. "Differentiation of Glacial Tills in Southern Ontario, Canada, Based on Their Cu, Zn, Cr, and Ni Geochemistry", The Wisconsinan Stage, Robert F. Black, Richard P. Goldthwait, H. B. Willman
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Geochemical investigations were performed on 109 samples of late Wisconsin glacial till from southern Ontario. The –0.037 mm size fraction was analyzed for Cu, Zn, and Cr by atomic absorption spectrophotometry and for Ni by colorimetry. Means and standard deviations (in ppm) for 109 samples (group 1) are: Cu, χ̄ = 23, σ = 6; Zn, χ̄ = 62, σ= 14; Cr, χ̄ = 51, σ = 15; and Ni, χ̄ = 28, σ= 8. The statistics were also computed for the following groups of samples: (2) oxidized till (67 samples); (3) unoxidized till (42 samples); (4) Erie Lobe till (22 samples); (5) Ontario Lobe till (13 samples); (6) Huron Lobe till (24 samples); and (7) Georgian Bay Lobe till (11 samples). Cr and Ni are slightly higher in group 3 than in group 2. Results of t and F tests performed on groups 4, 5, 6, and 7 suggest that the samples are derived from two populations; one characterized by the Erie Lobe samples (population E) and the other by samples from the Georgian Bay and Huron Lobes (population N). Population E has a higher content of all four elements than population N.
Results of a discriminant analysis suggest that the Ontario Lobe samples are derived from both populations. Three samples from the northwestern end of the Ontario Lobe show definite affinities with population N, whereas the others belong to population E. This difference suggests that the glacier which deposited the former till may have incorporated drift material from a northern source.
This preliminary investigation suggests that the application of multivariate statistical techniques to geochemical analysis of selected fractions of glacial deposits could provide another basis for differentiation of glacial tills.