USING THE GROUND PENETRATING RADAR METHOD FOR RESEARCH OF THE ANCIENT “VOROVSKAYA YAMA” COPPER MINE IN THE SOUTH URAL

• Main Authors: V. V. Noskevich, N. V. Fedorova
• Format: Article
• Language: deu
• Published: Ural State Mining University 2018-12-01
• Series: Izvestiâ Uralʹskogo Gosudarstvennogo Gornogo Universiteta
• Subjects: geophysical methods; georadar; ground penetrating radar; model; copper mine; Bronze Age; South Ural
• Online Access: https://www.iuggu.ru/en/4-18-8

Relevance. Integral to research in archeology, geophysical methods allow the study of buried monuments without destroying the soil layer and provide an opportunity to more accurately determine the place of future expensive and laborious archaeological excavations. In the steppe zone of the Southern Urals and the Mugodzhar Hills, about three dozen ancient copper mines are known, the development of which took place in the Bronze Age. At present, the bottom is covered with a thick layer of sediment, and the sides of an open pit have earthflows. In the study of ancient mines, it is important to determine the relief of pits and localise the sites of ore mining during their operation, which allows us to estimate the amount of ore mined and copper smelted. Purpose of the research. The determination of reflecting boundaries using the ground penetrating radar method between loose sediment deposits and copper-bearing rocks of the Bronze Age copper mine called ‘Vorovskaya Yama’, design of a three-dimensional model of an ancient open-pit mine and determination of the ore mining site. Justification of the ground penetrating radar method and research methods. The effectiveness of the ground penetrating radar method dependson the contrast of the dielectric permittivity of the layers in the studied environment. In this case, it is a sedimentary complex represented by manmade soils, and bedrock, which determine the surface of the pit during its development. The bedrock has a significant contrast in dielectric permittivity compared with the sedimentary complex at least twice. This circumstance makes it possible to determine the reflection response from the bedrock boundary. The ground penetrating radar survey at the Vorovskaya Yama open pit was conducted by radar SIR-3000 in nine parallel profiles with a length of 9–20 m and a distance of 2 m between the profiles. In the profiles, the survey was carried out with a step between surveyor stations of 0.1 m. To correctly interpret the results and take into account the current topography, a topographical survey was carried out. After processing the survey data, geological radar sections were formed in the profiles. Results of the research. After interpretation, two georadar complexes were identified in the sections: the lower, which is caused by the roof of the bedrock, and the upper one associated with man-made or processed soils. There are weak reflecting boundaries in the zone of the upper complex, which are presumably caused by traces of surface dumps, buried ditches and pits. In identifying the boundary between man-made soil and bedrocks on georadar sections, the main ‘indicators’ are the change in wave patterns of reflections in these environments, as well as the angular unconformity of the axes of synphasic reflections between them. After interpolating the boundaries between the profiles, a three-dimensional model of the relief of the mine was designed during the period of its development. The thickness of sediment varies within an open pit at the edge of the working from 0.5–1 m to 3 m at the bottomhole. The maximum depth of the pit in antiquity was 7 m. Conclusion. According to the results of the georadar survey at the mine, it was possible to confidently determine the relief of bedrock under a thick layer of later sediments. A three-dimensional model of an ancient open-pit mine was designed and the place of ore mining was localised. This data allowed us to estimate the depth and volume of workings during the development of a copper deposit in the Bronze Age.