Glacial activity during a part of the Proterozoic was probably similar to that of the Quaternary. Therefore, the studies of recently glaciated areas, of recent near-glacial and periglacial environments on land and in oceans, and investigations of the deposits and erosional features of the extensive areas that were covered by the Pleistocene glaciers can assist in the deciphering of Proterozoic glacigenic deposits: the environments of their formation and their stratigraphic sequences. Among glacial deposits, the most important is till. A relatively broad definition of till is used here to include flow tills, water-lain tills, and deformation tills besides the more conventional lodgement and melt-out varieties of till, since all of them, if correctly identified, imply glacial deposition, without or with penecontemporaneous resedimentation. Landforms will not be discussed here, as they seldom are preserved in Proterozoic glacial sequences. The macroscale and microscale glacial erosional features, glacio-dynamic deformation structures, fabric, and compositional characteristics will be considered as evidence of various glacial origins. The following environments of glacial deposition and varieties of till are recognized: (a) supraglacial and ice-marginal environment, producing subaerial varieties of supraglacial tills and subaquatic flow till; (b) subglacial environment, producing subglacial tills under a glacier that is either in contact with the substratum or is separated from the substratum by a thin layer of water or a cavity. Dropstones in aquatic sediments, particularly if they bear surface marks of glacial transport, are useful indicators of the presence of glaciers, but they alone do not make the aquatic sediment a till.

The names of the Huron, Erie, and Ontario Lobes imply that glaciers followed these lake depressions, but the flow patterns of these lobes were complex and changed several times during the Wisconsin glaciation. The sublobes of the southwestern part of the so-called Erie Lobe were more often an extension of the ice coming down Huron Basin, and ice from both basins participated in these sublobes. A review of the studies of Wisconsin-age deposits in the area of the three lobes indicates the emphasis that has been placed on investigations of tills by multiple methods, on paleontological studies of the interstadial and late-glacial deposits, and on radiocarbon dating. A threefold time-stratigraphic division of the Wisconsin Stage in this area is based upon synchronous fluctuations by several glacial lobes, and upon climatologic inferences from paleontologic studies. Early and late Wisconsin experienced maximum glacial advances; middle Wisconsin was dominated by interstadial retreats. The first Wisconsin glacial advance reached into the St. Lawrence Lowland only, and was followed by a glacial retreat during the St. Pierre Interstade about 65,000 radiocarbon yrs B.P. The second major glacial advance (by several lobes) went farther, but did not reach as far south as the late Wisconsin glaciation in Indiana and Ohio. In Pennsylvania and New York it was more extensive than the late Wisconsin, if the Olean Drift is indeed of early Wisconsin age. The source of ice was centered in the eastern Canadian Laurentide area. Mid-Wisconsin glacier margins retreated several times far into the Huron and Ontario Basins, or even north of them. Three main retreats were probably interrupted by two readvances which reached into the Erie Basin but not south of the Lake Erie watershed. Mid-Wisconsin time began more than 50,000 yrs B.P. and ended about 23,000 yrs B.P. During late Wisconsin time the major glacial advance in the western part of the region investigated reached its farthest extent south in at least three pulses: 21,000, 19,500, and 18,000 yrs ago. The oscillating retreats were interrupted by three documented readvances: about 17,000, 15,000, and 13,000 yrs B.P. The source of ice was primarily in the western Laurentide center. No evidence has been found here for the Valders readvance which took place in the Lake Michigan Lobe.

The type section for the Erie Interstade shows a well-developed beach between two layers of offshore sands. The section is underlain by a major late Wisconsin till, the Catfish Creek Till, and is overlain by the Port Stanley Till. The position of the buried beach 3 to 4 m above present Lake Erie level indicates that the interstadial lake, here named Lake Leverett, was lower than previously estimated and that it drained eastward, probably via the Mohawk Lowland, during an ice recession into the Ontario Basin. The Erie Interstade correlates well with a world-wide amelioration of the climate at about 15,500 yrs B.P. that separates two glacial maxima of the late Wisconsin-Weichselian, the older 20,000 to 17,000 yrs B.P. and the younger 14,800 to 14,400 yrs B.P.

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.