Magnetic susceptibility of permafrost soils of the forest catena in Central Yakutia

Abstract

The magnetic susceptibility (MS) of three types of permafrost forest soils (pale-yellow, pale-brown, and podzolic) formed on permafrost soil-forming rocks in the cryoarid climate of Central Yakutia for the first time was studied. It is noted that the studied permafrost soils develop within various high-altitude geomorphological levels of the ancient alluvial Central Yakut plain and form a regular zonal series from bottom to top, that is, with an increase in the absolute height of the terrain: pale-yellow gray ‒ pale-yellow typical and solodic ‒ pale-yellow leached ‒ pale-brown typical ‒ pale-brown podzolized and podzolic soils. At the same time, in this series of zonal soils, the values of their volume (VMS) and specific (SMS) magnetic susceptibilities also naturally decrease, due to the increased intensity of eluvial soil processes, such as solodization and podzolization in the genesis of these soils. The weighted average values of the specific magnetic susceptibility calculated for 9 sections of the studied permafrost forest soils, taking into account individual values of SMS and the thickness of their genetic horizons, changed for pale-yellow soils in the range of 21.6–42.1, pale-brown – 3.9–12.4, podzolic – 1.8–5.7 × 10–8 m3/kg. It is also established that based on certain values of the VMS of these soils, all the studied types of permafrost forest soils in Central Yakutia belong to the group of low-magnetic ones and differ in the values of volumetric magnetic susceptibility that do not exceed 100 × 10–5 Si units. Among the studied pedons of zonal forest soils of Central Yakutia, various types of their magnetic profiles are noted, which are determined by the geographical and genetic features of these soils.

Keywords

• cryoarid climate
• thickness of genetic horizons
• geographic­-genetic specifics