pdf № 327, March

DOI: 10.19110/geov.2022.3.1

In this paper we discuss results of complex geophysical works within the southern and middle segments of the West Timan fault. In the study area, based on the nature of potential fields (magnetic, gravitational), various areas of the West Timan fault were identified: the southern part (Beloborsk block), the central part (Nivshera block), and the northern part (Sindor block). These areas were studied by profile magnetometry on foot and express radon survey. The detailed magnetic survey revealed that the West Timan fault was clearly visible in the gradient sections of the magnetic field, with some degree of conventionality it can be identified within the regional maximum, and it is impossible to trace it in the zone of the regional minimum. Based on the interpretation of seismic data, the location of the West Timan fault has been clarified. The nature of the seismic record does not always allow identifying the exact location of the fold planes, only the difference in the record in individual blocks is clearly noted. The border area sometimes captures 5 km. The express emanation survey showed that the West Timan thrust, in general, was characterized by increased values of radon volumetric activity, where they are further traced to the territory of Timan, while areas of different intensity are distinguished.

Thus, with insufficient seismic knowledge and low differentiation of potential fields, the emanation radon survey can be used as an additional method for identifying and tracing tectonic dislocations. The complex of geophysical studies allowed clarifying the location of the West Timan fault.

Keywords: West Timan fault, potential fields, seismic profiles, volume radon activity.

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DOI: 10.19110/geov.2022.3.2

The article presents data summarization on magmatism and metamorphism of the Kanin-Timan-Pechora region and spatial analysis of the distribution of endogenous processes products in Late Proterozoic — Early Cambrian. A concentrated localization of the products of two mantle plumes, which gave rise to igneous complexes and relatively high-temperature regional metamorphism, was revealed in “Northern” and “Southern” areas separated from each other by an amagmatic area 250—300 km long with a relatively low level of regional metamorphic transformation of sedimentary rocks.

Keywords: magmatism, metamorphism, Timan megablock, Late Precambrian, mantle plume.

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DOI: 10.19110/geov.2022.3.3

The article is devoted to the analysis of the evidence of finding “amber” near the village of Kolchedan in the Middle Urals. This resin is not amber-succinite, but a rare type of fossil resin — krantzite. It is shown that the first written references to resin with properties of krantzite were much earlier than it was singled out as an independent species. A brief characteristic and assessment of its study is given. It is noted that “Kolchedan amber” is a rich and interesting material, which still awaits scientific processing.

Keywords: fossil resin, krantzite, Middle Urals.

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DOI: 10.19110/geov.2022.3.4

The results of studies of slag from excavations of the archaeological monument of the settlement of Kobylikha (Nenets Autonomous District) are presented. The analytical studies were based on optical and scanning electron microscopy and spectroscopic methods.

Our detailed mineralogical and geochemical studies resulted in determining siliceous-ferruginous composition of slags with impurities of aluminum, calcium, phosphorus, and potassium. Concentrations of Cu, Pb, Mg, Ni, Ti, Cr, V impurity elements are not large. According to the chemical composition, the viscosity and basicity of the melt were evaluated. The viscosity index indicates the fluidity of the melt. The basicity coefficient in the studied slags can be attributed to the group of acidic slags. Microprobe studies revealed the predominance of fayalite, wustite, iron-siliceous glass and reduced iron. The conducted studies allowed concluding on the use of a single ore from a single source. It is possible to assume the use of oxide easy-to-mine iron ores. Melting was carried out in a furnace at fairly high temperatures in the range of 1200—1400 ^oC and using fluxes. The slag cooled down rather slowly and directly in the furnace. Probably, the melting lasted for a long time. In the settlement of Kobylikha, metallurgical production had an average scale using simple technological schemes.

Keywords: archaeometallurgy, slag, iron production, Middle Ages, Bolshezemelskaya tundra.

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