GEOMORPHOLOGY OF THE SMERDYACH’E LAKE AND ITS SURROUNDING ROLL STRUCTURE

Abstract

Geologic-geomorphologic analysis of roll surrounding Smerdyach’e Lake basin and its neighborhoods were analyzed. Lots of researchers considered this basin as a footprint of meteor impact, but there is no incontestable proof of its impact origin. The result of meteor impact is almost general lacks of stratification in roll sediments, while stratification is well-defined abroad the roll on the vast postglacial terrace. Non-rounded debris of bedding rocks to a depth of non-less than 20 m was observed in upper roll horizons. They are almost absent outside the roll. Hill-and-ridged relief adjoining from the North-East side to the roll probably is a result of oblique impact of meteor (from the South-East to the North-West) whereby mass ejection is concentrated toward moving the impactor, although probably these forms are the result of eolian factor. Upper horizons of the Polya River terrace, as in the case of one of the roll test pit, penetrates alluvium involved in cryoturbation caused by cold snap during last glacial maximum and initiate to deposit before the epoch of last glacial maximum (23–20 thousand years ago). Layers intimately associated with meteor impact cover this alluvium, and this support the idea of meteor impact in the end of cold snap epoch or soon after it, i.e. to the period from 20 to 10 thousand years ago.