For the Altai mountainous region, especially the arid south-eastern part, the history of glacier fluctuations in Pleistocene and Holocene is still poorly known. The key plots were located in the Kargy valley (2288-2387 m a. s. l.) that is not currently affected by glaciations. The relative dating method was applied to define Pleistocene moraine chronology and configuration in the Kargy valley. Taking into account that relative dating methods are primarily based on weathering pat-terns, the mineralogy, porosity, and specificity of biological colonization as an agent of weath-ering were obtained for the moraine samples. Three moraine groups of different age (presumably MIS 6, MIS 4, and MIS 2) were identifies based on detailed investigation of morphological features. The moraine age was indirectly confirmed by the mesostructure of the moraine samples repre-sented by fine-grained shale: the older sample is characterized by a more developed fractal sur-face than the younger one. The growth of biota (crustose lichen and micromycetes) leads to initial biomass accumulation and subsequent rock disintegration. The accumulation of autochthonous fine earth on the rock surface was considered the initial stage of fine earth formation affected by biota.