ON THE ORIGIN OF FE IN SOME PODZOLIC SOILS FORMED ON CALCAREOUS PARENT MATERIALS IN THE CANADIAN ROCKY MOUNTAINS

The formation of Podzols in the Rocky Mountain Region of Alberta has been related to the presence of an easily weatherable volcanic ash component within the upper solum of these soils. A silty surficial deposit, comprising a mixture of volcanic ash and locally derived aeolian detritus, is the parent material for the upper solum of pedons occurring in stable landscape positions. Source areas for this locally derived aeolian detritus comprise highly calcareous materials. Weathering of the carbonate component of the locally derived aeolian material releases considerable amounts of iron and aluminum, sufficient to produce a Bf horizon given an appropriate environment. The presence of a Bf horizon in this region is insufficient evidence to implicate volcanic ash as a parent material component in the genesis of the pedon. Key words: Genesis, Rocky Mountain region, weathering of CaCO3, volcanic ash, local aeolian materials, Podzolic soils