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Proceedings of higher educational establishments. Geology and Exploration

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No 2 (2022)
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https://doi.org/10.32454/0016-7762-2022-2

GEOLOGIC AND PROSPECTING EDUCATION ISSUES

8-17 1090
Abstract

Russia’ national Programme for the Reproduction of the Mineral Resource Base cannot be implemented successfully without coordination between the quality of mining specialist training and the pace of developing mineral resources both in terms of solving methodological issues and providing stable funding.

The Sergo Ordzhonikidze Russian State Geological Exploration University carries out its activities aimed at training specialists for organizations of the Federal Agency for Subsoil Use. This direction is elucidated in the Programme and Development Strategy of the University for 2023–2027.

GEOPHYSICAL METHODS OF PROSPECTING AND EXPLORATION

18-23 739
Abstract

Introduction. Reservoirs composed of thin layers with different elastic properties exhibit the anisotropy of elastic properties. Anisotropic environments are studied using special seismic positioning systems that require large financial and time resources. However, neglecting pronounced anisotropy leads to misinterpretation of the data. Evaluation of the degree of anisotropy of a thin-layer stratum allows researchers to determine whether anisotropy could be neglected by conditionally considering the stratum to be isotropic.

Aim. To estimate the anisotropy of carbonate rocks on the scale of seismic surveys based on the data of geophysical well logging and petroelastic simulation.

Materials and methods. Models of carbonate rocks with different characteristics of pore space were created based on the Berryman and Backus methods. For these models, an analysis of the degree of anisotropy by Thomsen parameters was carried out. Acoustic and density logging data of a well located in Western Siberia were used for comparison with actual data.

Results. A numerical characteristic was found, the analysis of which helped to determine the significance of anisotropy before the application of the Backus method thus significantly reducing the number of necessary computational processes.

Conclusion. The obtained parameter of the degree of rock heterogeneity correlates well with Thomsen parameters responsible for anisotropy, which indicates the possibility of its use for assessing the anisotropy of strata.

24-30 422
Abstract

Background. The article provides arguments for the introduction of the “geophysical electrodynamics” term.

Aim. To justify the introduction of a new term “geophysical electrodynamics”.

Methods of substantiation. The limits of the applicability of Maxwell’s equations are studied. Additionally, some concepts are introduced, in particular, about a new paradigm in electrodynamics, about new equations in geophysical electrodynamics, about the differences between new electrodynamics and Maxwell’s electrodynamics, about the sources of toroidal and poloidal electromagnetic fields, about toroidal currents in Maxwell’s equations, about non-power electromagnetic fields, about the quantum effect in non-power electromagnetic fields, toroidal fields in the core of the Earth, mathematical achievements in the new paradigm, about the reproduction of sources of the electromagnetic field of the Earth, and effects in classical electrodynamics explained by geophysical electrodynamics.

Results. Responses to the above justifications were received.

Conclusion. Physical and mathematical justifications for the introduction of the term “geophysical electrodynamics” find confirmation both in the natural electromagnetic field of the Earth, and in a number of long-known classical effects in the standard Maxwell’s electrodynamics. Small but fundamental differences of one electrodynamics from another will reduce the number of effects unexplained from the standpoint of Maxwell’s equations, encountered in both theory and experiments on Earth.

GEOLOGY

31-38 474
Abstract

Background. Chromium ores are confined to stratified massifs of basic and ultra-basic composition. The Voikaro-Sinyinsky massif is part of the main hyperbasite belt of the Urals. Inside the hyperbasites of this massif, at the boundaries of tectonic flakes in particular, ultra-basic metamorphites are developed, constituting the zones of sharply variable thickness. During survey routes, a mechanical halo of scattering of ore fragments was found. When studying the ore stockpile, ditches opened the Labogeyskoe-2 chromite ore body, which belongs to the Pogureysky block of the Voikaro-Sinyinsky massif. In the ore occurrence area, harzburgites are predominantly developed with thin striped dunite aggregates in a small volume and individual dunite bodies of low thickness. Chromium ores are densely impregnated, medium- to coarse-grained. The amount of chromospinelides in the composition of ores сonstitutes 90—95%, the serpentine of irregular shape as well as the relics of olivine and emerald-green uvorovite grains, along with the single grains of pyrrhotite and magnetite are found in the interstitia (2—5%). Ores are massive, often cataclazed. The experience of studying this ore occurrence can serve as an analogue for a more effective study of similar ore occurrences. Aim. Evaluation of the Labogeyskoye-2 ore occurrence for the application of the information obtained and methods of its study in the study of a similar Levopayersk ore body, which will help save time and finances in the design and more efficient exploration.

Materials and methods. During the filming routes, a mechanical halo of scattering of ore fragments was detected. During the study of the ore collapse in 1966, the KM22—KM25 ditches were passed and the Labogeyskoye-2 chromite ore body was uncovered by the KM24 ditch. In 2013, during geological exploration at Labogeyskoye-2, 3 ditches (K50—K52) were passed and detailed gravimagnetic studies of Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements in 2011—2012 were performed.

Results. The Levopayerskoe ore body is probably the closest analogue of the Labogeyskoye-2 ore occurrence among the 24 ore occurrences, for which geological plans and calculation sections were compiled based on the results of mining and drilling operations.

Conclusions. The closest analogue of the Labogeyskoye-2 ore occurrence is probably the Levopayerskoye ore body. Therefore, further geological and exploration work at the Labogeyskoe-2 site should be carried out taking into account the conditions of occurrence of the similar Levopayerskoe ore body.

GEOLOGY AND PROSPECTING FOR SOLID MINERAL DEPOSITS

39-46 766
Abstract

Background. The value of natural radionuclide content in ores is a fundamental characteristic of any ore deposit, determining the possibility of studying, developing and enriching these ores, as well as manufacturing commercial products on their basis.

Aim. To evaluate the content of natural radionuclides in the rocks and ores of the Pizhem titanium deposit and to determine their mineral concentrators.

Materials and methods. A study of 15 core samples from wells within the Pizhem titanium deposit was carried out in the laboratories of IGEM RAS and VIMS using an “Ortec-65195-P/DSPecPlus” semiconductor gamma spectrometer.

Results. For the first time, a radiation safety assessment was carried out and the concentration of Ra226, Th232 and K40 natural radionuclides in the titanium ores and host rocks of the Pizhemskoye deposit (the Middle Timan) was determined. The mineral concentrators for Ra226, Th232 and K40 were found to be zircon, monazite (kularite) and hydromuscovite-illite, respectively. The lowest content of radionuclides was established for quartz (D2pz) and quartz-kaolinite (PR3mr3) sandstones of glass quality. The titanium ores of the deposit belong to the I class of mineral raw materials (Aeff < 0.74 kBq/kg), thereby being completely harmless to humans.

Conclusion. The low content of radionuclides in the studied ores allows them to be safely enriched, and the overburden sandstones of glass quality to be used without restrictions.

MINERALOGY, PETROGRAPHY, LITHOLOGY

47-56 492
Abstract

Background. Ammonite products are increasingly gaining in popularity. Ammonites are characterised by a variety of colour shades, shapes and sizes, making them suitable for manufacturing a wide range of souvenir and jewellery products. Russia enjoys significant resources of ammonites of interior and jewellery-ornamental quality; however, these materials remain insufficiently studied from the mineralogical point of view. This article presents the mineral composition and gemological characteristics of the Upper Jurassic interior jewellery ammonites of the Samara region for the first time.

Aim. To describe the stratigraphic position and mineral composition of interior jewellery ammonites of the Samara region.

Materials and methods. Late Jurassic ammonites (45 samples) were collected from a number of their main locations. The characteristic types of ammonites of interior-jewellery quality were distinguished and studied. Experiments included the determination of microhardness (25 determinations), density (12 determinations), luminescence features (10 samples), optical and petrographic analysis (5 thin sections), as well as the quantitative determination of mineral and chemical composition (3 samples), and electron probe studies (2 samples).

Results. Ammonites are characterized by the presence of a mother-of-pearl layer with multi-coloured iridescence. The ammonites under study consist mainly of apatite (21—70 wt. %) and calcite (21—87 wt. %) along with quartz, aluminosilicates, gypsum, pyrite, zeolites, goethite, ilmenite and organic matter. The chambers of ammonite shells are made of phosphorite and calcite. The walls and partitions of shells have completely lost their original aragonite composition and consist of apatite and calcite with pyrite inclusions. The increased content of Sr (up to 0.17 wt. %) and Ba (up to 0.01 wt. %) are recorded as trace elements in ammonites. Calcite contains the following trace elements (wt. %): Mg — 0.17, Mn — 0.17, Fe — 1.14, Sr — 0.11, and Y — 0.17.

Conclusion. The mineral and chemical (including microinclusions and trace elements) composition of interior-jewellery ammonites was established for the first time. The ammonites of the Samara region are of commercial interest as interior samples. Their shell fragments can be used in jewellery production. The ammonites under study can be collected along the coastal cliffs and beach area of the Volga river, thereby requiring no capital investments and producing no environmental pollution.

57-67 503
Abstract

Background. The article presents the first results of a mineralogical and petrographic study of the pumice of the Sarychev Peak volcano, Matua island, the Central Kuril islands.

Aim. To reconstruct the compositions of magmatic melts of a caldera-forming eruption of the proto-Matua volcano.

Materials and methods. The main research methods included an X-ray fluorescence spectral analysis to determine the content of petrogenic, rare and trace elements, as well as an electron-probe microanalysis to study variations in the chemical composition of mineral inclusions of pumice.

Results and conclusion. According to the content of SiO2 and the sum of alkalis, the composition of pumice varies from andesibasaltes (SiO2 = 55.94 wt.%) to dacites (SiO2 = 67.70 wt.%). According to the content of K2O, pumice can be classified as a moderate-potassium series of rocks. The inclusion minerals represented by plagioclase, amphibole, apatite and Fe-Ti oxides were crystallized at the same time from a water-saturated magmatic melt at a pressure of about 1.5–2.2 kbar. The igneous melt was enriched with volatile components of H2O, CO2, S, F and Cl.

HYDROGEOLOGY AND ENGINEERING GEOLOGY

68-79 592
Abstract

Background. The results of an engineering-geological study of rock soils and the products of their fault zones are considered on the example of samples selected in the sides of the Albazinskoe gold-bearing deposit located in the north of the Khabarovsk Krai.

Aim. To develop and implement a methodological approach, which includes laboratory determinations of the velocity of propagation of longitudinal seismic waves (“seismic speed”) using a “Pulsar-2.2” unit (methods of continuous and through sounding), as well as density, porosity and water absorption determinations along with obtaining information about the types of microstructure and microtexture, the mineral composition and mineral alteration features under the influence of metamorphism (using petrographical thin sections).

Materials and methods. For the collected rock soil samples the relationship between seismic velocity and physical properties indicators was evaluated (R-type cluster analysis programme). The products of fractural zones were studied in a laboratory according to a specially-developed methodological approach: extended (black clay) and reduced (crushed stone formations with debris). The microelement composition of the clay and gravel of argillites was determined for the first time, and the level of their pollution by toxic microelements (Zc index) was evaluated.

Results. On the basis of quantitative assessment of the relationship between indicators of rocky soils various properties identified using the cluster analysis program, an “anomalous” conclusion is obtained about the absence of the rock soil density effect on seismic properties, which can be explained by the textural and structural features, as well as by mineral composition and the consequences of metamorphism (cataclastic and blastogenetic features recorded on the microscale in thin sections).

Conclusion. The proposed methodological approach can be recommended for further studies of seismic, strength and physical properties of rocky soils during seismological and engineering-seismological studies of various territories.

80-91 1069
Abstract

Background. The relevance of the study lies in predicting the hydrogeological regime in the process of construction and operation of tailing storage areas. A complex study of the aeration zone and formation conditions of infiltration supply will make it possible to minimize the anthropogenic load on the hydrosphere and to develop measures for a reduction in the negative load on territories imposed to anthropogenic impact.

Aim. To determine the amount of infiltration supply in a designed tailing storage area.

Materials and methods. The studied territory is the southern part of the Talitsky section of the Verkhnekamsk salt deposit (Russian Federation). The studied objects included infiltration processes, weakly-permeable deposits, and drainage network. The applied methods involved mathematical modelling, mapping, and hydrometric works.

Results. The conducted works reflect the regularities characteristic of the drain of small rivers in the region under study. Melted snow waters play a leading role in feeding surface watercourses. The most intensive inflow of rainwater, corresponding to the periods of summer and autumn rain floods, on the rivers of the study area occurred in July 2017 and in October–November 2017. Some differences in the annual volume of the run-off distribution of this water flow are likely to be determined by a change in the characteristics of the water-collecting area occurring as a result of cutting down forests and preparing the territory for construction of a mining and processing plant.

92-99 681
Abstract

Background. In hydrogeological terms, the territory of the Barents-Kara shelf has not been studied in sufficient detail. The data on its hydrogeological zoning are based mainly on the results of research undertaken in the 1970s, when attempts were made to isolate artesian shelf basins according to a set of hydrogeological indicators of oil and gas content. Currently, the position of the basin boundaries can be adjusted using current data from oil and gas and geological zoning and the hydrogeological testing of wells.

Aim. To conduct the hydrogeological zoning of the territory of the southern part of the Kara Sea and the north of the West Siberian geosyneclise, including oil and gas structures — the South Kara syneclise and the Yamal-Gydan megasaddle, as well as to carry out a chemical analysis of groundwater of the Jurassic-Cretaceous aquifer complexes composing the sediments of the sedimentary cover of the West Siberian sedimentary basin.

Materials and methods. A cartographic method was used to analyze earlier maps and schemes of hydrogeological and oil and gas geological zoning of the Russian sector of the continental slope of the Arctic Ocean, and then to determine the boundaries of the identified artesian basins. For a chemical analysis of groundwater, the results of hydrogeological testing of wells drilled at the Zapolyarnoye oil and gas condensate field were used.

Results. The boundaries of two artesian basins — the South Kara submarine and the Yamal-Gydan semi-marine, corresponding to the same-name oil and gas prospective structures and having the same geological structure, were determined. Both basins are characterised by the presence of the main aquifer complexes of the Mesozoic hydrogeological floor of Western Siberia. When studying the composition of groundwater of the Zapolyarnoye deposit, it was found that the types of water change regularly with depth and an increase in the content of the hydrocarbonate ion due to the possible migration of fluids enriched with carbonic acid dioxide from the rocks of the foundation.

Conclusion. The determined basins are characterised by a wide distribution of oil and gas-bearing structures and the exploration maturity of the sedimentary cover. Both artesian basins are characterized by the distribution of groundwater of a unified composition and genesis.

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ISSN 0016-7762 (Print)
ISSN 2618-8708 (Online)