MONOSACCHARIDE STATUS OF PRE-MAZAMA AHB HORIZONS IN ALBERTA, CANADA

Palaeosols, formed prior to deposition of Mazama tephra (6600 yr B.P.) , are widespread in Alberta. Palaeo-Ahb horizons are readily identifia ble, with colors ranging from very dark gray to gray and brown. Establ ishment of fundamental and stable properties of the original organic m atter would facilitate the classification of these buried soils. Use o f a suite of eight monosaccharides divided the 15 palaeosols examined in this study into one group of three, possibly formed under Brown Che rnozemic soil-forming conditions or drier, and the remainder, possibly formed under Black Chernozemic soil-forming conditions. The former ha d C/N ratios approaching those of microorganisms and low xylose to man nose ratios. It is concluded that, because of the long time-window of surface stability between deglaciation and the Mazama tephra fall, pre -Mazama palaeosols can only be studied on a site-specific basis. Group ing these palaeosols, based on their pre-Mazama tephra deposition only , is not realistic. Synthesis of a unified hypothesis of palaeoenviron mental conditions is, therefore, not possible using only their monosac charide status.