Kolyma lowland is an ideal natural object for studying the peculiarities of soil formation in continental region of the Arctic. Here, natural or climatic, geocryologic and geobotanic zonalities are well expressed. Geographical soil distribution of the similar rocks can be traced via all tundra subzones up to the forested tundra.

Different forms of watershed relief and relevant soilforming rocks (ice- wedge complex - IWC, or edoma sediments) defined the existence of zonal variety of loamy cryo-hydromorphic non-gleyed soils, the cryozems or CR (Sokolov, 1980), in the soil cover and tundra gley soils or TGS which are characteristic for landscapes of the North Subarctic.

CRs are formed on edoma cover season thawing layer of the deposits in climatic optimum. TGS belong to Holocene watersheds of thermocarst genesis which is associated with paleohydromorphic meadow - bog stage of landscapes development (Kaplina, Lozhkin, 1979; Gravis et al., 1986)

The CR geography is closely connected with edoma area, thus the CRs can be found in all Subarctic subzones. Zonal CR peculiarities are represented in dynamic properties of the soil. Morphogenetic properties of the TGS vary in dependence of their topography within an ancient thawing basin and a period of previous lowland - hydromorphic (alass-bottom land and meadow - bog) phase of soil formation.

Thermocarst determined the separation of edoma surfaces at mezo- micro- and nano-levels that was expressed in a special ratio between gley and non- gleyed soil in the soil cover of modern watersheds.

Hence, the phenomenon of TGS in the Arctic soil cover is associated with climatically dependent geomorphologic evolution of the landscapes in Holocene.

L. A. Fominykh
Institute of Soil Science and Photosynthesis, RAS
142292 Pushchino, Moscow Region
RUSSIA
Phone: 923-35-58
Fax: 7(0967)79-05-32
E-mail: sotnikov@issp.serpukhov.su