About the building stones of the Eneolithic cromlech, sanctuary, and burial constructions near Shakhtar village (Dnipropetrovsk region, Ukraine)

The article presents the results of petrographic research of building stone that was used for the construction of a cromlech, sanctuary, and the ceiling of the Eneolithic burials No. 20 – 22 from the kurgan No. 29 near Shakhtar village, Nikopol rayon, Dnipropetrovsk oblast. The purpose of this work was to establish a probable place for mining the stone blocks and rubble used in the construction. As a result of petrographic and X-ray fluorescence analysis, it was determined that the studied rocks can be divided into two groups, namely granitoids and limestones. The group of granitoids included tonalites, plagiogran- ites (trondhjemites), altered granite gneiss, and feldspar crystal from pegmatite. All the limestones were represented by spherical lay- ered aggregates, which most likely belong to oncoids – carbonate structures that form as a result of cyanobacteria growth. The studied samples from the materials of the cromlech and the sanctuary of burial No. 22 were represented by plagiogranitoids, pegmatoid granite, and limestones. The first of them served as the main material for the construction of the cromlech. Carbonate aggregates together with the granites were also used as a backfilling when installing wooden pillars of the cult complex associated with the burial. The plates covering the burials No. 20 and 21 were made of tonalites. All the studied granitoids are typical rocks for the area where the excavations took place. In the Middle Dnipro Area, plagiogranitoids are represented by the rocks of the Dnipropetrovskyi, Surskyi, Saksahanskyi, and Inhuletskyi complexes of the Archaean. Plagiogranitoids of the Dnipropetrovskyi complex are the most common in the studied area. They occur here in the middle and upper reaches of the Solona River and along the rivers of Bazavluk and Bazavluchok upstream the Sholokhove Reservoir. The closest to the excavation site are the occurrences of plagiogranitoids, which are exposed on the right bank of the Solona River, opposite the village of Shakhtar. In this area, pegmatoid granites are found in the form of veins that intersect plagiogranitoids. In the area of excavations, carbonate oncoids are found in the Sarmatian limestones of the Neogene. Most often they are found as the uncemented specimens that spilled out of the limestones. Today, such structures occur on both banks of the Kakhovske Reservoir, located south of the village Shakhtar. However, in ancient times there may have been closer outcrops of these rocks, as the Sarmatian limestone occurrences are common in the immediate vicinity of the excavation site, namely between the rivers Bazavluk and Solona, near their confluence, and the middle and upper reaches of the Chortomlyk River. As a result of the research, it is proved that in the valley of the river Solona during the Eneolithic, there began the active extraction of stone raw materials for mound construction, which was continued in later epochs, particularly, in the Scythian time.