Depth Profiles of Geochemistry and Organic Carbon from Permafrost and Active Layer Soils in Tundra Landscapes Near Lac de Gras, Northwest Territories, Canada

Permafrost and active layer samples from 24 sites were collected to examine the vertical and spatial distribution of water content, organic matter content and soluble cations. Water, organic matter and soluble ion contents varied across depths. Vertical patterns also varied between terrain types. Near-surface solute enrichment of permafrost was evident at some sites in each terrain type, but the majority of sites had lower cation contents in near-surface permafrost than in the active layer. Active layer organic materials from peatlands and wetland terrain were solute rich in comparison to mineral soils of till blanket, till veneer or esker terrains at similar depth. In the Lac de Gras area, organic soils are enriched with solutes relative to tills or glaciofluvial deposits, and since the organics are primarily at the surface or within the active layer, the active layer is solute rich with respect to underlying mineral soil permafrost.