River deltas boast ecosystem richness, but their efficient conservation and management require consideration of the full spectrum of natural phenomena, including those which are geological. Few specialists have explored the issue of deltaic geological heritage (geoheritage), and the relevant knowledge remains scarce and non-systematised. This paper proposes the first classification of this geoheritage. Five categories are distinguished: entire-delta geological phenomenon, delta-associated “purely” geological features, delta-associated features resulting from geology–ecosystem interactions, geological features occasional to deltas, and geoarchaeological localities in deltas. Chosen as a case example, the Don River delta in the southwestern part of Russia possesses geoheritage of these categories, except for the latter. The relevant unique geological features differ by their types and ranks. Of particular interest is the phenomenon of a self-cleaning environment which prevents mercury concentration in the soil despite pollution from natural and anthropogenic sources. The complexity of the deltaic geoheritage, its co-existence with the rich biodiversity, and the aesthetical issues make geopark creation in river deltas a sensible venture. Relevant proposals have been made for Malaysia and the Netherlands–Belgium border, and the Don River delta in Russia also presents an appropriate location for geopark creation.
Spiders (Aranei) of the coast of Taganrog Bay (the Sea of Azov) and the Don River delta
