Pollen and lithological data from the Bukovynka Cave deposits as recorders of the Late Pleistocene and Holocene climatic change in the eastern foothills of the Carpathian Mountains (Ukraine)

Abstract

The study of clastic sediments of the BukovynkaCaveshows biotic and climatic changes during the Middle Pleniglacial (the Trapeznyi Chamber), Late Glacial and Holocene (the Sukhyi Chamber) in the south-eastern part of the Ukrainian Carpathians. The artesian BukovynkaCaveis located near the villageof Stal’nivtsi(the Chernivtsi region), in the PrutRiver basin. It is developed in the Miocene gypsum strata. The Quaternary clastic infilling of the cave, as well as mammal taphonomy has been previously studied in the Trapeznyi Chamber (Vremir et al., 2000; Ridush, 2004; Ridush et al., 2012), whereas palaeomagnetic research and its palaeoenvironmental implication has been provided for the Sukhyi Chamber (Bondar and Ridush, 2014). The results of pollen and grain-size studies of clastic deposits in both chambers, supported by mammal finds, are presented in this paper. In the Chernivtsi region, the pollen study has been previously performed (without ¹⁴C-dating) on the Upper Pleistocene loess-paleosol section of Snyatyn and on the Onut site of the Holocene flood-plain deposits of the River Prut (Artyushenko et al., 1982).

39 samples from the cave sediments have been processed for grain-size analyses using the ‘pipette’ technique by Kachinsky (1965). In order to get pollen from clastic sediments, the following technique has been applied: heating with 10% HCl and 10% KOH, cold treatment with HF, disintegration in a solution of Na₄P₂O₇ and separation in heavy liquid (CdI₂ and KI) with a specific gravity 2.2. The abundance and good preservation of pollen show that the cave chambers turned periodically into sedimentation traps. Mammal bones are also mostly well preserved. Re-deposited pollen are abundant in the Trapeznyi Chamber but occur very rarely in the Suchyi Chamber. The present-day vegetation near the cave is a meadow-steppe surrounded by Carpinus-Quercus forest. The high proportion of Pinus sylvestris pollen in the surface soil samples (30-40%) does not correspond to the limited role that pine has in the modern vegetation. On the basis of this fact, pine pollen in the cave deposits are also regarded as over-represented because of its ability to travel farther on the wind than other pollen and its better preservation in rocks.