The Intensity of Geochemical Weathering in a Toposequence Formed on Granitic Till at Thor Lake, Northwest Territories

Abstract

<p>From standard cell data and a principal component analysis, the intensity of geochemical weathering in the toposequence developed at Thor Lake, Northwest Territories was determined as follows: Degraded Dystric Brunisols formed on the dry crestal sites were weakly weathered; the Orthic Humo-Ferric Podzol found on moist terrace and slope sites as well as the Gleyed Humic Podzol situated adjacent to the thaw pond were moderately weathered in relation to the other soils; whereas the Gleyed Humo-Ferric Podzol located in the moist linear depressions revealed the maximum intensity of geochemical weathering, that is, the maximum removal of mobile ions and the greatest alteration from a stable parent material.</p> <p>It was established that the iron-magnesium bearing minerals were initially weathered from the parent material; calcium, sodium, and then potassium were removed by the soil solution from the A horizon; iron, aluminum, and phosphorus were the prime depositional cations in the B horizon with silicon increasing as a residual cation in the A horizon.</p>