Oleshkivski Sands as a hierarchically built natural system

Оleshkivski Sands (Oleshia) are one of the morphosculptures on the Left bank of the lower part of Dnipro river, which is formed on alluvial and periglacial deposits. The article clearly identifies the location of these sands among other morphosculptures of the Left bank of the lower part of Dnipro. In view of the ambiguity, two regions of the Left Bank are considered separately – nearby arenian sandy-loamy geocomplexes with the presence of extremely specific sandy hilly-depressions geocomplexes and the territory of the hilly-lowland plain (Kardashynka lowland), which is located between the Dnipro delta and sands massives of the Kelegei arena.Oleshia consists of seven hilly-sanded arenas and six inter-arenial sanded flat plains. Accordingly, the area of Оleshkivski Sands is 219.9 thousand hectares, almost 80 % of which are sanded arenas. Arenas are represented here as hilly sandy plains and depressions. These sandy plains divided by sand types such as hilly (hillock, hillock-dune and hilly), hilly-ridge and flat-wavy, depressions – by flat-wavy, ridge-hollow, wavy-shallow depressions and ridge-shallow depressions. Such types of relief forms are represented by the following microforms of aeolian genesis: hillocks, hills, parabolic dunes, aeolian fields, deflation depressions and also by microforms of fluvial genesis: hilly-ridges, depressions among hilly sandy massifs, gally (redundans), inter-ridge depressions (inter-ridge hollows).On the surface of sandy massifs, especially in places where the sands are exposed, relief nanoforms are formed, which are represented by small riffles, nabkhas, blowing furrows, tafonies and also by aeolian trains, cut-off lobes, cliffs, cornices.This system of forms of relief of the Oleshkivski Sands testifies to the complex and various processes of their formation, but special attention should be paid at sand ridges, especially those with the parallel ridge-hollow spatial organization. They, for example, in the south of the Kinburn arena became the basis for the formation of the aeolian-hydrogen landscape that is unique for the territory of Ukraine.The author associates the creation of the Oleshіa ridge-hollow geocomplexes with the probable catastrophic floods (floodstreams). It is advisable to consider these ridges as a manifestation of giant ripples (diluvial dunes), which are often covered by deposits with different nature of formation. This is evidenced by the variety of typology of relief forms on the territory of the Oleshkivski arenas. Thalassogenic, suffusion-subsidence and anthropogenic factors also deserve special attention in characterizing of shaping the relief of the region.Key words: the Left bank of the Lower Dnipro, Оleshkivski Sands, hierarchy of relief forms, sandy arena, aeolian processes, fluvial forms.