Abstract—: Soils on red-colored calcareous substrates occupy vast areas in Eastern Siberia. The objects of this study are located in the southern part of the Lena–Angara Plateau and are represented by loamy-clayey soils with a high content of total and dithionite-soluble iron. The mineralogical composition of the clay fraction reflects the spatial heterogeneity of red-colored substrates characterized by the illite–chlorite association of clay minerals with a predominance of dioctahedral minerals (micas and, in some cases, dioctahedral chlorites). Red-colored residual-calcareous soils reflect the development of structural metamorphism and textural differentiation of the soil mass. The intensity of these processes at the macro- and microlevels depends on the absolute altitude of the area, which determines the degree of climate humidity. Texturally differentiated soils (raw-humus podzolic soils, or Calcaric Albic Rhodic Luvisols) are formed in the most humid conditions at altitudes above 1000 m a.s.l. They are characterized by the vertical homogeneity of the parent material, weak color differentiation with preservation of the reddish tint in the upper horizons, and distinct differentiation of the clay fraction with a reduced thickness of the illuvial horizon due to the close occurrence of the hard carbonate substrate. At lower altitudes, the signs of clay illuviation are less pronounced, though they can be traced in the profiles of raw-humus podzolized or clay-illuvial brown soils (burozems) (Calcaric Chromic or Calcaric Rhodic Luvisols).