Clay mineralogy of Cryosols formed in an ultra-continental climate of Siberia

Abstract

The clay mineralogy of Cryosols formed in several regions (the Anabar and the Alazei plateaus and the Central Yakutia plain) of the north-eastern part of Siberia (Yakutia) was studied to assess weathering activity of minerals in soil environment. The studied soils are represented by shallow profiles located in the hard to reach areas that are not well known from previous soil survey and proper “Palevaya (Pale) soil” from the international forest ecological monitoring network. Based on XRD data of the < 1µm fractions, the minor mineralogical change was observed in the shallow soils. The decrease in proportion of the most sensitive to weathering smectitic structures (mixed-layer illite-smectite) was revealed in the profile from the Anabar plateau. Despite the strong difference in pH values, the horizons ranging in depth are rather similar in the deeper and proper Cryosol (“Palevaya (Pale) soil”) from the Central Yakutia plain. The minor difference is related to partial reduction in chlorite proportion occurring in A and B horizons. The present findings revealed that vertical pattern of clay mineral distribution can be affected by the modern stages of weathering activity in Cryosols formed in cold environment of ultra-continental climate.