The relative weathering of a sequence of five palaesols formed in different parent materials, including bedrock of phonolitic composition, is described and assessed. The three lower palaeosols (units 3-5) are considered to be of interglacial origin. The saprolite (unit 5),in phonolite, formed prior to deposition of the lower Brunhes-age till, is considered to be as old as the Brunhes Matuyama boundary (0.73 myr). The other two palaeosols in this group (units 3 and 4), derived from loess and till, respectively, formed over middle to late Brunhes time under palaeoclimates that were wetter (and presumably warmer)

Mahaney, W. C. and Hancock, R. C. V. 1993. Late Quaternary stratigraphy and geochemistry of the R47 section, Rouge River Basin, south-central Ontario, Canada: correlation with Scarborough Bluffs. /ourna/ of Quaternary Science, Vol. 8, pp. 167-1 78.ABSTRACT: Quaternary glacial diamictons in section R47, overlying Ordovician shale in the Rouge River Basin of south-central Ontario, are considered to be representative of older and younger Wisconsinan glacial diamictons in the field area. Field characteristics, clast composition, mineralogy, particle size and geochemistry permit delineation of two units within the sequence and subdivision of deposits that correlate with Sunnybrook and Halton diamictons of Wisconsinan age. No Wisconsinan interstadial deposits are present in the section; however, outwash sandy gravel capping the Halton diamicton was probably emplaced by a high-energy stream draining b r d dQwtermn/ into Lake Iroquois just prior to the incision of the Rouge Valley in the later Wisconsinan (ca. 11 000-1 2000 yr BP). A buried palaeosol, which developed in this sandy gravel and in overlying aeolian sediment, shows partial leaching of carbonates and a slight increase of clay in the palaeosol solum. The main clay-mineral transformations in the buried palaeosol appear to involve the degradation of illite and illite-smectite accompanied by the production of vermiculite and minor amounts of chlorite. The ground soil capping the buried palaeosol is formed in colluvium emplaced 200 & 80 yr BP following a local forest fire; the ground soil Ahk horizon gives an age of 4000 yr in the future, probably as a result of nuclear bomb testing effec'ts on modern radiocarbon. The presence of an N C profile in the ground soil system, although thin, indicates that surface soils may form rapidly.The geochemistry of the two Wisconsinan diamictons shows similar calcite and Si02-corrected mean element concentrations, with slightly elevated levels of Ca, Sr, Hf and Lu in the younger deposit. Both diamictons are geochernically quite different from the shale bedrock in the area, indicating that the bulk of transported sediment came from outside the area.