Characteristics of residual and colluvial soils developed on granite and of the associated pre-Wisconsin landforms in north-central New Brunswick

Abstract

An area in north-central New Brunswick of approximately 20 km2, where tors are common, was found to be undisrupted by glaciation. The soils in this area are developed on grus and appear to be of pre-Wisconsin age. In both residual Podzolic and colluvial Brunisolic soils, gibbsite was found to be present in significant amounts. The gibbsite content in the clay fraction of the residual soil increased with depth whereas the reverse occurred in the colluvial soil.The evidence indicates that gibbsite could have formed in a climate similar to the present one and that it is not stable in the present soil environment due presumably to the presence of organic matter.Except for the presence of gibbsite in the clay fraction, the characteristics of the residual soil are similar to those of soils of similar texture of late Wisconsin age from the same province.