Character and chronology of natural events modifying the Palaeolithic settlement records in the Ihrovytsia site (Podolia, the Ukraine)

Ihrovytsia, an important site of Middle and Upper Palaeolithic settlement, is situated in the central part of the Podolia region (western Ukraine). During the excavations (33 m2) in the years 1988–1989 and 1996, archaeological materials were found in a complicated stratigraphic (geological) situation in the 3 m thick loess-soil sequence (MIS 5-1). The excavations undertaken in 2010 and 2011 encompassed the 60 m long profile across the promontory occurring between two small valleys. This long profile permitted examination of the lateral variability of the deposits, and reconstruction of the sequence of accumulation, destruction, and redeposition processes. Field observations were supplemented with basic laboratory analyses and TL dating. Two solifluction series occurring in the profile are covered and in places also separated by loess. The lower one (probably formed at the end of MIS 5 and at the beginning of MIS 4) consists of the packages composed of the material from the A and B horizons of the Gorohiv soil (S1). The upper solifluction series (probably formed at the beginning of MIS 2) consists of loess and the material of the Dubno interstadial soil (MIS 3). A gley paleosol of unclear stratigraphic position occurs over the solifluction cover in places. The artefacts of the Middle Palaeolithic cultural layer (II), made using the Levalloise technology, were found in the lower solifluction series. This series is cut by at least two generations of mammalian burrows, in which the bones of steppe–tundra animals (probably from the first phases of MIS 4) have been found. Two Upper Palaeolithic cultural layers (I and I-A) are a single cultural complex but represent different settlement episodes and occur in different stratigraphical positions. The majority of cultural materials (distinguished as I-A) occurs within the upper solifluction series. In many places the both solifluction series are superimposed and even partially mixed, which resulted in the mixing of the Middle (II) and Upper Palaeolithic (I-A) cultural materials. The cultural layer I occurs in situ on the surface of gley soil dated at about 20 ka. The ice wedge casts, evidencing cold and dry climate phases of the younger parts of MIS 4 and MIS 2, additionally disturbed the arrangement of artefacts occurring near them.