Cryogenic relicts in the topography and loose sediments of the Middle Protva drainage basin

Abstract

A number of geological-geomorphic cryogenic relicts was studied in the Middle Protva drainage basin, including polygons up to 50-100 m wide on interfluves and river terraces. Earth veins and cryoturbations belong to three generations, one of Late Moscow and two of Valdai age. Two layers of covering loams were formed on interfluves, principally in lake and bog environments during the Early and Late Valdai time, and were reworked by cryogenic processes. Relict dells (primarily erosional landforms) are typical of the upper parts of waterdivides. Terraces scarps are masked by thick (up to 6-7 m) slope deposits and transformed into «terrasouvals». Alluvium of small rivers also shows «periglacial» features (thickness two to three times more than «normal», indications of lacustrine regime, «cold» pollen spectra). Cryogenic relicts influence the landscapes of the region as well as the present-day morpholithogenesis.