Structure of large flat-bottom depressions on loess interfluves of eastern Azov region (on the example of “Chervonaya Pad'”)

Abstract

Geological and geomorphological structure of the “Chervonaya Pad’”, one of the largest orientated depressions of Eastern Azov region, was considered. The study is based on the results of the analysis of remote-sensing data and new geological data obtained during manual drilling and studying the coastal outcrops. Features of the morphological similarity between the neighboring large depressions and “Chervonaya Pad’” was revealed. It is evidence of the unity of their origin. This allows us to consider “Chervonaya Pad’” as a model object for research. The features of the geological structure and morphology of the “Chervonaya Pad’” show that the depression is a denudation form developed in the cover of loess deposits as a result of the impact of airflow on the surface. According to the paleosol stratigraphy, it was revealed that the main stage of the formation of the depression was in the end of the Middle Pleistocene.Based on the material obtained, the authors verify the existing hypotheses of the formation of the large flat-bottom depression relief of the Eastern Azov region. It is revealed that the previously proposed mechanisms for the formation of large depressions (thermokarst, erosion-suffusion, loess subsidence, estuary-lake) do not consistent with the actual data on the geological-geomorphological structure of the “Chervonaya Pad’”. The authors propose the hypothesis of the eolian-denudation (deflation) origin of large depressions of the Eastern Azov region.