SHORT-TERM HOLOCENE CLIMATIC CHANGES PALYNOLOGICALLY RECORDED IN DEPOSITS AT ARCHAEOLOGICAL SITES IN SOUTHERN UKRAINE

Palaeoclimatic rhythms (each 300-500 yrs in duration) are recorded in the pollen and soils of 25 archaeological sites in the Ukrainian steppe, from the Lower Danube to the Sea of Azov. During Mesolithic times, the Early Preboreal and Early Boreal warm phases were marked by the spread of south-boreal forest-steppe (with an admixture of Quercus and Corylus), whereas xeric grassland was typical for the Late Preboreal and Late Boreal cold phases. A temperate climate was established at the beginning of the Atlantic. Mesophytic steppe and Quercetum mixtum existed first, and Carpinus appeared later. Neolithic people appeared after an arid phase around 7 ka BP and later, lived in a benign climate. At the threshold of V and IV millennia BC (early Chalcolithic times), a cooling happened. The Late Atlantic optimum around 5.5 ka BP was marked by a maximum of broad-leaved trees, and cultivation of Cerealia. Reduction of forests and the disappearance of Carpinus took place in a cooler and drier phase around 5 ka BP. From the beginning to the optimum of the Holocene, a trend to climatic improvement occurred with oscillations in warmth and humidity. This step-like development is similar to the pattern of Black Sea transgressive-regressive phases.

Forest-steppe expanded to the south during the Early and Late Subboreal cool and wet phases (4.6-4.1 and 3.5-3.0 ka BP). During the latter, Late Bronze settled economies appeared (some with cultivation of Cerealia). During the dry Middle and Late Subboreal phases (4.1-3.5 and 3.0-2.6 ka BP), almost complete deforestation and the spread of dry steppe occurred. Only nomadic tribes existed then. During the wet and cool Early Subatlantic (2.6-2.2 ka BP, Scythian times), the last expansion of forest-steppe happened. During 2.2-1.7 ka BP, Artemisia steppe spread (dry and warm climate). The wet phase around 1.5 ka BP was marked by mesophytic steppe, which was replaced by grassland at 0.7-1.1 BP (Saltiv culture), and by mesophytic steppe during the Medieval Optimum (X-XII centuries). During XIII to XIX centuries, the increase in steppe xerophytes and the decline in broad-leaved species indicate the dry ‘Little Ice Age’. These rhythms coincide with those proved by the Saki Lake sedimentary archive (Gerasimenko et al., 2011). Black Sea maximum transgressions correspond to warm and dry phases.