LATE GLACIAL AND HOLOCENE EVOLUTION OF LANDSCAPESON THE TERRITORY OF SPOROVSKY RESERVE (BELARUSIAN POLESIE)

Based on the results of palynological, sedimentological, radiocarbon and OSL studies, the changes that occurred during the Late Glacial and Holocene with landscapes of the territory of the Sporovsky Reserve were defined. Using archaeological research methods, it was found that the active use of the region’s landscapes by human has taken place since the Neolithic.


INTRODUCTION
The preliminary results of geoarchaeological and paleogeographic studies on the territory of the Sporovsky Biological Reserve are presented.
Research reserve is located on the territory of Belarusian Polesie in Brest region, beyond the border of the last glaciation (Fig. 1).

Late glacial and holocene evolution of…
Investigated site is characterized as a large peat-bog area with sandy hills in the basin of the Yaselda River (Pripyat tributary) and Lake Sporovskoe (Fig.  2). For the reconstruction of the palaeogeography of Sporovsky Reserve geological, geomorphological and geoarchaeological works were conducted on a peat-bog west of Lake Sporovskoe (profile "Sporovo II") and near the archaeological site "Kakoryca-4" located on a sandy hill (52°23'36.657"N 25°17'34.355"E) (Fig. 3).

METHODS
The interdisciplinary research approach was applied. Field geological, geographical, cartographic works and archaeological excavations were carried out at the selected points. Exposed alluvial, lake sediments, peat-bog and sand (aeolian?) deposits were analyzed using palynological, sedimentological, radiocarbon analyzes (14C) and OSL dating. To create cartographic materials, a technique based on the analysis of remote sensing data was used. The multispectral and panchromatic optical-electronic sensing data from artificial Earth satellites, as well as manned and unmanned aerial photography materials, were processed and analyzed (Fig.2,3, 4).

RESULTS
Based on the sedimentological analysis of deposits from profiles Sporovo II, KO3, KO4, KO8, KO9, MW9 and Pit 3, lithological diagrams and the section across the study area were drawn up ( Fig. 5-8). The cross-section and spatial reference of the boreholes were carried out using geodetic measurements (GNSS method) and DEMs based on aerial photography data.    The analyzed sediments from Sporovo II profile were divided into five lithological members, reflecting a typical for Belarusian Polesie structure of sediments, when alluvial sands and lacustrine gyttja (I, II) are covered by peats with different percentage of organic content (III, IV, V) (Fig. 7). Palynological studies were conducted at profiles Sporovo II, KO4 and KO8. Local pollen assemblage zones (LPAZ) were identified based on cluster analysis (CONISS) and visual evaluation of pollen spectra. Five pollen zones, corresponding to the Holocene periods, were determined for the profile Sporovo II (Fig. 9), considered as a reference. The chronology of paleogeographic events was restored based on radiocarbon dates obtained for the Sporovo II, KO4, and KO8 profiles, as well as the correlation of local pollen zones with regional pollen zones (RPAZ) of the Holocene for Belarus. The radiocarbon dating of peat samples from the Sporovo II core is presented in Table 1.    (Fig. 10).

DISCUSSION AND PRELIMINARY CONCLUSIONS
Obtained data and literary sources [3], [4] show the development of the territory of the Sporovsky Reserve during the Holocene. According to palynological and radiocarbon analyses, it was found that in the Early Holocene on the territory of Sporovsky Reserve there was a large lake in which carbonate gyttja deposited [5] (Fig. 7). The beginning of this accumulation was palynolgical dated at Preboreal (Fig. 9 -SPII-1). The same sedimentation type occurred in Belarusian lakes (Polesie and Poozerie regions) in Younger Dryas and Preboreal [6]. The accumulation of calcareous gyttja in Boreal period is also common in these regions. Around the same time we could observe increase in the tendency of lake level change in these regions [6]. In Sporovo, alike in other reservoirs in this region, the formation of carbonate sediments reflects an important stage of lake development, connected with a considerable general warming of the climate at the beginning of the Holocene [6]. At the time of intensive sedimentation of calcareous deposits the lakes were oligotrophic-mesotrophic and the sediments were poor in organic matter [7] (Fig. 7 -II member). In the end of Boreal and beginning of Atlantic (8190±90 BP, 7494-6866 cal. yr BC) we can observe peat accumulation on calcareous deposits in profile Sporovo II (Fig. 9). This time was characterized by the accumulation of peats (Early Atlantic) and after that silty peats until 5600±70 BP (4598-4331 cal. yr BC) -end of the Atlantic, which may be connected with warm and dry climate in the Subboreal period [4]. This can be reflected in the water level in Lake Sporovskoe, just like it did in Lake Bobrovichskoe [6] in this region at the same time. It should be noted that the result of radiocarbon measurement of a peat sample from Sporovo II at a depth of 155-161 cm ( Table 1 -5190±110 BP) was most likely distorted due to contamination of the sample with younger deposits. With a high probability the territory of the archaeological site "Kakoryca-4" was used in agricultural activities. This is evidenced by field observations in adjacent areas, as well as the striped image structure of the hill surface on the DEM, based on unmanned aerial photography materials (Fig. 4B).