CHANGING RIVER REGIME OVER THE BLACK SEA CATCHMENT: PALEOCHANNELS, PALEOFLORA AND ANCIENT HUMAN SETTLING

River runoff from the East European Plain played an important role in Black Sea level changes during the Late Glacial until the connection with the Mediterranean Sea was re-established and later during the Holocene. River paleohydrology is therefore an important issue in the Black Sea's cultural history. We studied river regime and runoff in the past using three data sets: (a) the dimensions of river channels preserved on floodplains and low terraces, (b) paleoclimate reconstructions based on modern analogues to ancient floristic assemblages, and (c) the hypsometrical position of human settlements in river valleys in different epochs. The major results are as follows: (1) From 16-11 kyr BP, river runoff into the Black Sea from the east European part of the catchment basin was three times that of the present. Selected Upper Paleolithic sites located as low as on modern floodplains and dated at around 20 kyr BP (Avdeevo site on the Seim River, Kostenki-21 site on the Don River) point to early river incision that possibly resulted from a period of high runoff before the Last Glacial Maximum. (2) In the Holocene, three types of paleohydrological epochs are distinguished (data from the Dnieper River sources): (a) low floods, low lake levels - Neolithic, Bronze Age, 8-10th century AD (Medieval climatic optimum); (b) average floods and lake levels - Late Iron Age, 11-13th century AD, 14-17th century AD, and present; (c) high floods, high lake levels - Mesolithic, Early Iron Age, 18-19th century AD (Little Ice Age). The early Middle Ages was one of the driest epochs, as indicated by widespread buried floodplain soils and major settlements on river floodplains, such as Gnezdovo Viking settlement in the vicinity of Smolensk city.