Use of geophysical methods on settlement complexes of the Circumpolar region (based on historical settlement of Ust-Voikarskoe)

Purpose. The settlement of Ust’-Voykarskoe is situated in the Lower Ob region (Shuryshkarsky raion of the Yamal-Nenets Autonomous Okrug, Russia). Its materials characterize the aboriginal culture of the peoples who lived in north-western Siberia in the period of the late Middle Ages. The site is just one of the few multilayered settlement complexes with a frozen cultural layer that became an object of archeological research in Siberia. A historical interpretation of the site was offered by the first researchers of the settlement (A. G. Brusnitsyna, N. V. Fedorova). They believe that the site in question is known as an «ostyak» (Khanty) town of Voikar according to some folklore and written sources. The cultural layer is represented by organic deposits (mainly, accumulated wastes of wood processing) of high power. Results. The permafrost has preserved the wooden architecture of the site quite well. It is represented by ruins of buildings of various designs and purposes. In the cultural layer, the ruins occupy several levels belonging to the different periods of settlement functioning. According to the dendrochronological analysis conducted by the dendrochronologist M. A. Gurskaya, we recognize a residential development of the beginning of the 14th century, then the middle or the last third of the 17th century - the beginning of the 18th century, and also the beginning of the 19th century. The complex of archaeological and geophysical work conducted included various methods of geophysical exploration tested on the site for the benefits of archeology. We used electromotography, magnetometry and georadiolocation on layers with similar structure. Based on the results of the two-dimensional analysis of the data of electrotomography, we distinguished a layer characterized by a lower resistance to the overlapping soil layer and underlying permafrost. This layer extends up to 4-5 meters deep from the top surface of the hill. Based on the results of the 3D inversion of the electrotomography data, two long parallel linear conductive structures were identified in the body of the hill. Their presence was confirmed by magnetic survey and georadiolocation. When compared to the archaeological realities, they were interpreted as buildings arranged in two rows. Conclusion. Additional excavations are required to verify our assumption. The specificity of the cultural layer structure, as well as a low contrast in the physical properties of wooden structures and their environment, do not allow us to determine the location of certain buildings by the methods of geophysical exploration. The restrictions in the application of geophysical methods that we faced may complicate the possibility of getting operational information on the structure of an archaeological site when planning the protective and rescuing archeological work. However, it is obvious that by removing the soil cover we tend to intensify the processes of the cultural layer’s seasonal thawing, which is a threat to its informative potential.