CONDITIONS OF THE PLEISTOCENE INYA SERIES FORMATION YALOMAN-KATUN AREA OF THE ALTAI MOUNTAINS
The paper presents conditions of the Inya series formation of Yaloman-Katun area of the Altai Mountains that takes up Katun and Chuya river valleys and forms high terraces basement there. Main attention is devoted to layer-by-layer description and to evaluation of structure, constitution and geomorphologic location of stratotype of Inya series and the reference section of the flood cyclite separated in it. Grain size measurements of flood cyclite deposits were realized. Successive vertical stratification of the section layers without its significant erosion suggests of putting down of the Inya series deposition area. The main genetic indicators using for determination of the Inya series formation condition are taken into consideration. Basic horizon is presented to be channel facies of mountain river alluvium. The rest of stratotype is formed in lake basin in which a mountain river flowed. Criterions of lacustrine genesis of the Inya series are next indications: burying of coarse angular blocks and its accumulation across the road from area of its rockfall in the basin when underlying layers formed; good preservation of river delta deposits flowing in the basin with weak hydrodynamic; vertical profile being described by increasing of grain size up-section is specific for lake deposits. Benchmarking lithological study of deposits provided a basis for separating flood cyclite allows to refer it to the river and lacustrine deposits. The evidences of sudden superflooding been responsible for catastrophic debacle of ice-dammed lakes in the the Inya series are not detected.