ИСТИНА

The object of the study were microbiomorphic complexes in the pedosediments at Early Acheulian site within Lori Plateau in Northern Armenia, with the purpose of reconstructing the paleoclimatic conditions during early human migrations out of Africa. At the study site (Karakhach), lithic tools typical of the Acheulian culture dating about 1.4-1.9 Ma were found. The Karakhach section included a total of 14 layers of colluvial and alluvial deposits with detritus components and abundant Early Acheulian stone tools. The sections of studied pedosediments were shown contain material from former paleosols that developed higher up the slope, then were eroded and transported by colluvial processes and finally redeposided in an inverted order at the foot of the slope. Between gray colored clastic layers consisting of boulders and pebbles cemented by coarse sand there were fine-textured brown loam layers 1 and 11 without clastic fraction, brown fine-textured volcanic ash – layer 9 and two light brown lenses of ash within layer 10. Microbiomorphic complexes were studied in all layers. Abundant well preserved phytoliths and small broken parts of diatoms were found in all layers from pedosediments. The assemblage of phytoliths had a complex composition but morphotypes of the C3-type plants prevailed in absolutely all samples. Only two layers (1 and 11) contained about 3-4% phytoliths of xeromorphous plants which are typical for the C4-type of photosynthesis. Clastic layer 12 which contain incorporated fragments from the upper horizons of the same original paleosol showed several phytoliths of xeromorphous plants also. Almost all samples contained similar phytolith complexes from plants belonged to different ecological niches – dry steppe, wet meadows and forests (coniferous and deciduous). Such composition is typical for topographic depressions, where various fine particles have been brought from higher grounds and accumulated. The paleoclimate of the study area at the Early Acheulian times can be defined as contrast in the rainfall regime during the year with the high atmospheric temperature range. The summer was hot and particularly dry and the winter was somewhat cold and wet.