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Geology

Geology
  • Date submitted
    2020-08-20
  • Date accepted
    2021-11-30
  • Date published
    2021-12-17

Indicator role of rare and rare-earth elements of the Northwest manganese ore occurrence (South Africa) in the genetic model of supergene manganese deposits

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The authors analyzed the content of a number of rare and rare-earth elements in the rocks of the Northwest manganese ore occurrence, confined to the Neoarchean dolomites of the Malmani series of the Transvaal Basin. 30 samples of manganese ores and host rocks were analyzed by ICP-MS and XRF methods. Average values of Post-Archean Australian Shale (PAAS) were used as the geochemical standard for data calculation and normalization. The concentrations of elements normalized on PAAS reveal the LREE anomaly in manganese ores. Positive Ce and negative Y–anomalies indicate the hydro-genetical type of sedimentation of ore minerals from manganese-bearing aqueous solutions. This is consistent with the ratios of the elements: Ce and Y SN /Ho SN , Ce and Nd, Fe – Mn – (Co + Ni + Cu) × 10. A clear correlation between the contents of rare-earth elements in manganese nodules and the underlying Malmani dolomites indicates their close genetic relationship. Negative Ce and positive Y–anomalies in manganese wad minerals indicate differences in the conditions of their formation. The manganese wad formed earlier than the rest of the ore with the active participation of microorganisms.

How to cite: Evdokimov , A. N., & Pharoe , B. L. (2021). Indicator role of rare and rare-earth elements of the Northwest manganese ore occurrence (South Africa) in the genetic model of supergene manganese deposits. Journal of Mining Institute, 252, 814-825. https://doi.org/10.31897/PMI.2021.6.4
Geology
  • Date submitted
    2021-08-05
  • Date accepted
    2021-11-30
  • Date published
    2021-12-17

Morozkinskoye gold deposit (southern Yakutia): age and ore sources

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The paper presents the results of the comprehensive isotope geochemical (Re-Os, Pb and δ 34 S) study of sulfide mineralization of the Morozkinskoye deposit. The ore zones of the deposit are localized in the syenite massif of Mount Rudnaya, which is located within the Central Aldan ore region (southern Yakutia). Gold mineralization is represented by vein-disseminated or vein type mineralization and is manifested in acidic low-temperature metasomatites – beresites (Qz-Ser-Ank-Py). For the first time we obtained an age estimate of the gold mineralization ~ 129 ± 3 Ma, which the synchronism of the hydrothermal ore process in the beresites, which formed the Morozkinskoye deposit, and magmatic crystallization of the syenites of Mount Rudnaya (~130 Ma). The osmium initial isotopic composition of the studied sulfides indicates a mixed mantle-crustal source of sulfide mineralization. New lead isotopic data of syenites indicate the predominance of mantle lead and an insignificant role of the lower – crust lead, while the isotopic composition of pyrite denotes the presence of the upper crustal material in the ore genesis. The sulfide δ 34 S values vary from –2.3 to +0.6 ‰ and indicate a predominantly magmatic source of sulfur in the ores.

How to cite: Guzev , V. E., Terekhov , A. V., Krymsky , R. S., Belyatsky , B. V., & Molchanov , A. V. (2021). Morozkinskoye gold deposit (southern Yakutia): age and ore sources. Journal of Mining Institute, 252, 801-813. https://doi.org/10.31897/PMI.2021.6.3
Geology
  • Date submitted
    2021-03-18
  • Date accepted
    2021-11-30
  • Date published
    2021-12-17

Deformations assessment during subway escalator tunnels construction by the method of artificial freezing of soil for the stage of ice wall formation

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The work is devoted to the study of the processes of displacement and deformation of the surface during the escalator tunnels construction of the subway by the method of artificial freezing of soils. The features of the construction and freezing technology, the rocks characteristics in which the escalator tunnels made are considered. The data of specially organized, full-scale surveying observations of deformations on the earth surface are presented. The main factors influencing deformation processes in the frozen strata of a layered inhomogeneous rock mass with inclined tunneling are determined, the complexity of the predictive task and the need to simplify the design scheme are shown. The work is focused on the assessment of the least studied geomechanical processes of soil heaving-uplifts and deformations during the periods of active and passive freezing stages. When studying the displacements processes of the earth surface and rock mass, the finite element method and analysis of the obtained data using field observations of displacements were used. A simplified calculation scheme is proposed for modeling, which allows taking into account the uneven influence of frozen rocks of an inhomogeneous layered rock mass with a large inclined tunneling. The satisfactory convergence of the data of field surveying observations on the earth surface and the results of modeling geomechanical processes for the period of active and passive freezing stages is shown. The proposed calculation scheme is recommended for the prediction of deformation at the stages of underground construction, characterized by the development of the most dangerous tensile deformations of buildings and structures on the surface.

How to cite: Volokhov , E. M., & Mukminova , D. Z. (2021). Deformations assessment during subway escalator tunnels construction by the method of artificial freezing of soil for the stage of ice wall formation. Journal of Mining Institute, 252, 826-839. https://doi.org/10.31897/PMI.2021.6.5
Geology
  • Date submitted
    2021-06-22
  • Date accepted
    2021-11-30
  • Date published
    2021-12-17

Increasing the efficiency of rare earth metal recovery from technological solutions during processing of apatite raw materials

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The issues of complex processing of mineral resources are relevant due to the depletion of available raw materials. So, it is necessary to involve technological waste, generated during the processing of raw materials, to obtain valuable components. In the process flow of apatite concentrate treatment using the sulfuric acid method, a large amount of phosphogypsum is produced with an average content of light rare earth metals (REMs) reaching 0.032-0.45 %. When phosphogypsum is treated with sulfuric acid solutions, a part of REMs is transferred to the sulfate solution, from which it can be extracted by means of ion exchange method. The study focuses on sorption recovery of light REMs (praseodymium, neodymium and samarium) in the form of anionic sulfate complexes of the composition [ln(SO 4 ) 2 ] – on polystyrene anion exchanger AN-31. The experiments were performed under static conditions at a liquid-to-solid ratio of 1:1, pH value of 2, temperature of 298 K and initial REM concentration in the solutions ranging from 0.83 to 226.31 mmol/kg. Thermodynamic description of sorption isotherms was carried out by the method based on linearization of the mass action equation, modified for the ion exchange reaction. As a result of performed calculations, the authors obtained the constants of ion exchange equilibrium for Pr, Nd and Sm, as well as the values of the change in the Gibbs energy for the ion exchange of REM sulfate complexes on the AN-31 anion exchanger and the values of total capacity of the anion exchanger. Calculated separation factors indicated low selectivity of AN-31 anionite exchanger for light REMs; however, the anion exchanger is suitable for effective recovery of a sum of light REMs. Based on the average value of ion exchange equilibrium constant for light REMs, parameters of a sorption unit with a fluidized bed of anion exchanger were estimated.

How to cite: Ponomareva , M. A., Cheremisina , O. V., Mashukova , Y. A., & Lukyantseva , E. S. (2021). Increasing the efficiency of rare earth metal recovery from technological solutions during processing of apatite raw materials. Journal of Mining Institute, 252, 917-926. https://doi.org/10.31897/PMI.2021.6.13
Geology
  • Date submitted
    2021-11-30
  • Date accepted
    2021-11-30
  • Date published
    2021-12-17

Innovative ways to control dust and explosion safety of mine workings

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Ensuring dust and explosion safety during underground coal mining is one of the most important tasks of industrial safety and labor protection departments. The main method of preventing explosions of coal dust settled in mine workings is to process them with stone dust (rock dusting). The traditional methods of quality control of rock dusting include radioisotope, optical and chemical methods. To implement them, the devices are equipped with environmentally harmful radioactive elements, expensive optical sensors, desiccants and replaceable flasks with chemical reagents, which increases the cost of analysis and its duration. The measurement error of these devices is 10 % or more. The main purpose of the study is to develop and substantiate a new method for monitoring the dust and explosion safety of mine workings, which will be devoid of the disadvantages of the methods mentioned above. It is proposed to evaluate the quality of rock-dust distribution by a fundamentally new way – thermogravimetric. The method was tested on the dust of coal mines in Kuzbass and the Vorkuta basin, including dust samples taken in mines with actual explosions. The article presents the results of experimental studies of the processes of thermal destruction of coal and stone dust mixtures. The non-overlapping intervals of the thermogravimetric reaction are identified: moisture yield (35-132 °С); volatile matter yield from coal (380-580 °С); thermal degradation of limestone with carbon dioxide yield (650-850 °С). Methods and mathematical dependencies for processing significant and qualitative identification characteristics of thermogravimetric curves in determining the content of non-combustible components in a sample of mine dust are considered.

How to cite: Romanchenko , S. B., Naganovskiy , Y. K., & Kornev , A. V. (2021). Innovative ways to control dust and explosion safety of mine workings. Journal of Mining Institute, 252, 927-936. https://doi.org/10.31897/PMI.2021.6.14
Geology
  • Date submitted
    2021-01-19
  • Date accepted
    2021-07-27
  • Date published
    2021-09-29

Geological and structural characteristics of deep-level rock mass of the Udachnaya pipe deposit

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For hard rock massifs, structural disturbance is a key indicator of mining structure stability. The presence of intersecting structural elements in the massif reduces rock strength and leads to formation of potential collapse structures. In addition to that, disjunctive deformations that penetrate rock strata serve as channels for fluid migration and connect aquifers into a single system. It was established that the largest of them –faults of east-northeastern, northeastern and northwestern directions – form the kimberlite-bearing junction of the Udachnaya pipe. These faults represent zones of increased fracturing, brecciation and tectonic foliation, distinguished from adjacent areas by increased destruction of the rock mass. Specifics of tectonic fracture distribution within structural and lithological domains are determined by the presence of multidirectional prevailing systems of tectonic fracturing, as well as by differences in their quantitative characteristics. With some exceptions, the main systems form a diagonal network of fractures (northeastern – northwestern orientation), which is typical for larger structural forms – faults. Despite the differences in dip orientation of the systems, most of them correspond to identified directions, which is typical for both kimberlites and sedimentary strata. Overall disturbance of the massif, expressed in terms of elementary block volume, reaches its peak in the western ore body. For such type of deposits, friction properties of fracture structures have average values. Consideration of geological and structural data in the design and development of new levels of the deposit will allow to maintain the necessary balance between efficiency and safety of performed operations.

How to cite: Serebryakov , E. V., & Gladkov , A. S. (2021). Geological and structural characteristics of deep-level rock mass of the Udachnaya pipe deposit. Journal of Mining Institute, 250, 512-525. https://doi.org/10.31897/PMI.2021.4.4
Geology
  • Date submitted
    2021-03-16
  • Date accepted
    2021-07-27
  • Date published
    2021-09-29

Allocation of a deep-lying brine aquifer in the rocks of a chemogenic section based on the data of geophysical well logging and 2D seismic exploration

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Advancement in the production of potassium fertilizers is an important strategic task of Russian agricultural industry. Given annually growing production rates, the reserves of discovered potassium-magnesium salt deposits are noticeably decreasing, which creates the need to ensure stable replenishment of the resource base through both the discovery of new deposits and the exploitation of deep-lying production horizons of the deposits that are already under development. In most cases, deposits of potassium-magnesium salts are developed by underground mining. The main problem for any salt deposit is water. Dry salt workings do not require any additional reinforcement and can easily withstand rock pressure, but with an inflow of water they begin to collapse intensively – hence, special attention is paid to mine waterproofing. Determination of spatial location, physical and mechanical properties of the aquifer and water-blocking stratum in the geological section represent an important stage in the exploration of a salt deposit. The results of these studies allow to validate an optimal system of deposit development that will minimize environmental and economic risks. On the territory of Russia, there is a deposit of potassium-magnesium salts with a unique geological structure – its production horizon lies at a considerable depth and is capped by a regional aquifer, which imposes significant limitations on the development process. To estimate parameters of the studied object, we analyzed the data from CDP seismic reflection survey and a suite of methods of radioactive and acoustic well logging, supplemented with high-frequency induction logging isoparametric sounding (VIKIZ) data. As a result of performed analysis, we identified location of the water-bearing stratum, estimated average thickness of the aquifers and possible water-blocking strata. Based on research results, we proposed methods for increasing operational reliability of the main shaft in the designed mine that will minimize the risks of water breakthrough into the mine shaft.

How to cite: Danileva , N. A., Danilev , S. M., & Bolshakova , N. V. (2021). Allocation of a deep-lying brine aquifer in the rocks of a chemogenic section based on the data of geophysical well logging and 2D seismic exploration. Journal of Mining Institute, 250, 501-511. https://doi.org/10.31897/PMI.2021.4.3
Geology
  • Date submitted
    2020-05-28
  • Date accepted
    2021-07-27
  • Date published
    2021-09-29

On the applicability of electromagnetic monitoring of hydraulic fracturing

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The purpose of this work is to assess the possibilities of using electromagnetic monitoring to study the development of a fracture system generated by hydraulic fracturing (HF) with a specified position of the controlled source. The option with the source (a vertical electric dipole) located in the interval of the oil-bearing formation and ground-based measurements was chosen as the most promising monitoring plan. We have built a geoelectric model equivalent to the system of hydraulic fractures, divided into 11 zones corresponding to HF stages. For the selected model, mathematical simulation was performed by solving the direct problem considering the impact of the steel casing, the presence of which reduced the effect. Despite this fact, no strong distortion of electromagnetic field anomaly was observed above the HF zone. Analysis of the simulation results at different HF stages showed that as new hydraulic fractures appeared and were filled with electrically conductive proppant, the total effect increased. The data on electric field anomaly demonstrated maximum deviation from the background level of more than 2 %. Provided that the studied formation is characterized by sufficient electrical conductivity, its magnetic field also becomes informative.

How to cite: Grigorev , G. S., Salishchev , M. V., & Senchina , N. P. (2021). On the applicability of electromagnetic monitoring of hydraulic fracturing. Journal of Mining Institute, 250, 492-500. https://doi.org/10.31897/PMI.2021.4.2
Geology
  • Date submitted
    2021-06-10
  • Date accepted
    2021-07-27
  • Date published
    2021-09-29

Defects of diamond crystal structure as an indicator of crystallogenesis

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Based on the study of a representative collections of diamonds from diamondiferous formations of the Urals and deposits of the Arkhangelsk and Yakutian diamond provinces, we established patterns of zonal and sectoral distribution of crystal structure defects in crystals of different morphological types, identified the specifics of crystals formed at different stages of crystallogenesis and performed a comprehensive analysis of constitutional and population diversity of diamonds in different formations. We identified three stages in the crystallogenesis cycle, which correspond to normal and tangential mechanisms of growth and the stage of changing crystal habit shape. At the stage of changing crystal habit shape, insufficient carbon supersaturation obstructs normal growth mechanism, and the facets develop from existing surfaces. Due to the absent stage of growth layer nucleation, formation of new {111} surfaces occurs much faster compared to tangential growth mechanism. This effect allows to explain the absence of cuboids with highly transformed nitrogen defects at the A-B 1 stage: they have all been refaceted by a regenerative mechanism. Based on the revealed patterns, a model of diamond crystallogenesis was developed, which takes into account the regularities of growth evolution, thermal history and morphological diversity of the crystals. The model implies the possibility of a multiply repetitive crystallization cycle and the existence of an intermediate chamber; it allows to explain the sequence of changes in morphology and defect-impurity composition of crystals, as well as a combination of constitutional and population diversity of diamonds from different geological formations.

How to cite: Vasilev , E. A. (2021). Defects of diamond crystal structure as an indicator of crystallogenesis. Journal of Mining Institute, 250, 481-491. https://doi.org/10.31897/PMI.2021.4.1
Geology
  • Date submitted
    2020-06-11
  • Date accepted
    2021-03-30
  • Date published
    2021-06-24

Crystal morphology of spherical viruses

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The article discusses modern views on the structure of spherical virus capsids, which have the shape of icosahedrons (icosahedral viruses). Each face of icosahedron is composed of a single-layer closest packing of protein globules, which can have different orientation relative to the edges of icosahedron. If the lines of globules are parallel to the edges of icosahedron, then the capsid has a point symmetry group I h (with symmetry planes), if they are not parallel – the symmetry group I (without planes). From a mathematical point of view, in both symmetry groups there are series that unite equally (up to similarity) arranged capsids. They are connected pairwise by transitions to dual forms (homologous series). A hypothesis is formulated that the largest spherical viruses can have even more diverse and complex capsid structures. Along with icosahedron, their basic forms can be any simple shapes, allowed in I h and I symmetry groups (8 in total). A suggestion is made that transitions within similarity series and between homologous series have a phylogenetic significance. There are known spherical viruses of both symmetry groups. For example, the SARS-CoV-2 coronavirus has a symmetry group I h and belongs to a well-known series. The crystallographic approach allows to construct a strict morphological classification of spherical viruses. This is important for their early recognition and separate examination. The article demonstrates practical application of crystal morphology in the study of viral systems – an urgent problem of geoecology and life protection.

How to cite: Voytekhovsky , Y. L. (2021). Crystal morphology of spherical viruses. Journal of Mining Institute, 248, 190-194. https://doi.org/10.31897/PMI.2021.2.3
Geology
  • Date submitted
    2020-07-27
  • Date accepted
    2021-03-30
  • Date published
    2021-06-24

New data on the granite pedestal of the monument to Peter the Great “The Bronze Horseman” in Saint Petersburg

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In order to expand and popularize knowledge about the stone decoration of Saint Petersburg, we present new data on the mineralogy and petrography of the famous Thunder-Stone, the parts of which were the basis for the monument to Peter the Great – the legendary “Bronze Horseman”. In the course of studying geological documentation of the monument's granite base, we examined the mineral composition and internal structure of granite, as well as the fragments of a pegmatite vein and veinlets found in it. 25 single-mineral samples were collected from the available micro-scaled shear fractures within the pedestal surface and studied by electron microscopy, electron probe and X-ray phase analysis. It was established that K-Na feldspar in the granite composition was represented by microcline, whereas micas were represented by annite-siderophyllite and muscovite. Accessory minerals included monazite, xenotime, thorite, zircon, rutile, apatite, fluorite, Ti-, Nb-, Ta-bearing minerals, uranium phosphates. The presence of topaz is characteristic of pegmatites. The revealed structural and textural features of four granite boulders in the monument pedestal, as well as mineralogical and chemical composition of their rock-forming and accessory minerals, showed the similarity of this rock to Precambrian biotite-muscovite granites and topaz-containing pegmatites (stockscheiders) of the late formation phase of the Vyborg rapakivi granite massif. The research results are considered as the basis for further geological and mineralogical study of the Thunder-Stone origin and determining the place of its separation from the primary source.

How to cite: Bulakh , A. G., Popov , G. N., Yanson , S. Y., & Ivanov , M. A. (2021). New data on the granite pedestal of the monument to Peter the Great “The Bronze Horseman” in Saint Petersburg. Journal of Mining Institute, 248, 180-189. https://doi.org/10.31897/PMI.2021.2.2
Geology
  • Date submitted
    2020-08-03
  • Date accepted
    2020-12-13
  • Date published
    2021-06-24

Tectonic and magmatic factors of Li-F granites localization of the East of Russia

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We have investigated tectonic and magmatic factors of Li-F granites localization of the East of Russia. The study is based on the ideas of Far Eastern geologists about the deep structures of intraplate activity. A model of a source structure with mantle heat sources and ore-forming magmatic complexes was used. We carried out a special metallogenic analysis of the East of Russia as applied to the rare metal-tin-bearing formation of subalkaline leucogranites, including Li-F ones. Source structures are the main factor in the tectonic and magmatic development of the East of Russia, localization of ore-forming granites and the formation of rare-metal-tin ore regions. On deep layers of source structures there are areas of the mantle and earth's crust decompaction, heat, magmas and fluids sources, as well as granitoid cryptobatholiths. Relatively large massifs of leucogranites, small intrusions of tin monzonitoids and Li-F granites are concentrated near the modern surface. The source structures correspond to the rank of the ore region. The source structures in the South of the region are: Badzhalskaya, Miao-Chanskaya, Ippato-Merekskaya, Hogdu-Lianchlinskaya, Arminskaya, etc.; in the North: Pevekskaya, Kuiviveem-Pyrkakayskaya, Kuekvun-Ekiatapskaya, Iultinskaya, Telekayskaya, Central Polousnaya, Omsukchanskaya, etc. Three types of ore regions have been identified according to the degree of source structures and Li-F granites erosion. We have also outlined the patterns of source structures evolution and their place in the geological history of ore-bearing granites. A classification of source structures and its comparison with the classifications of regional intrusives and metallogenic subdivisions are proposed. It has been established that, despite the diversity of tectonic, geological and petrological settings in the East of Russia, the intrusions of Li-F granites are regulated by the same tectonic and magmatic factors. The tectonic and magmatic factors of Li-F granites localization in the East of Russia are identified and classified as geophysical, orogenic, geoblock, magmatic, metasomatic and disjunctive.

How to cite: Alekseev , V. I. (2021). Tectonic and magmatic factors of Li-F granites localization of the East of Russia. Journal of Mining Institute, 248, 173-179. https://doi.org/10.31897/PMI.2021.2.1
Geology
  • Date submitted
    2020-08-20
  • Date accepted
    2021-04-01
  • Date published
    2021-06-24

Features of the mineral and chemical composition of the Northwest manganese ore occurrence in the Highveld region, South Africa

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The Northwest manganese ore mineralisation is located at a relative distance from traditionally known manganese mining areas in a new manganese-bearing region (Highveld) in the Northwest Province, Republic of South Africa. The ore occurrence was studied on farms: Buchansvale 61 IQ, Weltevreden 517 JQ, Rhenosterhoek 343 JP and Kafferskraal 306 JP. The data obtained from studying the geology of the area pointed out to interests regarding the development criterias for search of similar ore mineralisations in the northwest region of South Africa. The ore occurs predominantly in the form of powdered manganese wad, manganese nodules and crusts, confined to the karstic structures of the upper section of the dolomites. X-ray powder diffraction (XRD), Scanning electron microscopy with energy dispersive link (SEM-EDS) and X-ray fluorescence were utilized to unveil the mineral and chemical composition of the ore samples. The present study therefore presents the results on both chemical and mineral composition of manganese ores, and their depth and longitudinal distribution. Karstic areas causing an increased local thickness of the ore body were identified. The geochemical and microspcopic study of the ores indicates their supergene nature. The main ore minerals includes cryptomelane, lithiophorite, purolusite, hollandite and romanechite associated with impurity components of Ba, Ce, Co, La, Cr, Zn and V.

How to cite: Evdokimov , A. N., & Pharoe , B. L. (2021). Features of the mineral and chemical composition of the Northwest manganese ore occurrence in the Highveld region, South Africa. Journal of Mining Institute, 248, 195-208. https://doi.org/10.31897/PMI.2021.2.4
Geology
  • Date submitted
    2020-09-10
  • Date accepted
    2020-11-25
  • Date published
    2021-06-24

Formation conditions of noble metal mineralization in sulfide cobalt-copper-nickel ores of Kamchatka (on the example of Annabergitovaya Schel ore occurrence)

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The authors present research results, the purpose of which is to study the specifics of noble metal mineralization and its genesis in sulfide cobalt-copper-nickel ores of the Kamchatka nickel-bearing province. The paper is dedicated to one of its many ore occurrences called Annabergitovaya Schel (Annabergite Gap). The material composition of platinoid, silver, gold, bismuth and tellurium minerals, as well as sulfarsenides in the ores of this occurrence was investigated. Based on the data of mineral formation sequence and the use of geosensors, conclusions were drawn regarding the genesis of noble metal mineralization. Formation of platinoid minerals, silver and gold at the Annabergitovaya Schel ore occurrence is mainly associated with the epigenetic effect of post-ore granitoids on ore-bearing intrusion rocks of the Dukuk complex of the cortlandite-norite formation and on syngenetic ores. An early association of noble metal minerals is represented by sperrylite, irarsite, and rare unnamed phases of Pt + Ir + Te. Irarsite and Pt + Ir + Te phases were formed at the contact-metasomatic stage. Sperrylite can be assumed to be of magmatic origin. Silver sulfides and tellurides, silver and palladium bismuth tellurides, and native gold were formed at the late, hydrothermal-metasomatic, stage. The occurrence conditions of mineral parageneses, associated with noble metal mineralization, correspond to the formation of shallow-depth metasomatic rocks (≤5 km). Sub-developed quartz-feldspar metasomatites, associated with the formation of early platinoid arsenides and sulfarsenides, are in equilibrium with circumneutral solutions (pH of 4.5-6.5) at temperatures of 350-600 °C. Late hydrothermal association with Pd, Ag and Au minerals is close to propylites and was formed at pH values of 4.5-6.5 and temperature of 150-350 °C.

How to cite: Novakov , R. M., Kungurova , V. E., & Moskaleva , S. V. (2021). Formation conditions of noble metal mineralization in sulfide cobalt-copper-nickel ores of Kamchatka (on the example of Annabergitovaya Schel ore occurrence). Journal of Mining Institute, 248, 209-222. https://doi.org/10.31897/PMI.2021.2.5
Geology
  • Date submitted
    2020-11-20
  • Date accepted
    2021-03-30
  • Date published
    2021-06-24

Petrochemical features of tholeiites from the Shaka ridge (South Atlantic)

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The article presents original data of chemical composition of tholeiitic basaltoids and andesites, dredged from the Shaka Ridge (South Atlantic) in the course of field research in spring 2016 on the scientific expedition vessel “Akademik Fedorov”. The analytical part of the work on estimating the contents of petrogenic, trace and rare-earth elements was carried out using the classical method (“wet chemistry”), X-ray fluorescence analysis (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). The studied samples demonstrate elevated concentrations of large-ion lithophile elements, or LILE, (Ba, Rb, Pb) and light rare earth elements, or LREE, (La, Ce, Nd, Sm) relative to high field strength elements, or HFSE, (Nb, Ta) and heavy rare earth elements, or HREE, (Dy, Yb, Lu). The specifics of trace element geochemistry suggest a significant contribution of crustal or subduction components to the magmas of the Shaka Ridge. Discrimination diagrams of basaltoids and allied rocks with fields of different geodynamic settings indicate that they were formed in the setting of the mid-ocean ridge basalt (MORB). The reason behind the appearance of subduction and crustal marks in the rocks is possibly associated with assimilation of crustal matter by magmas or lies in their inheritance from the mantle source.

How to cite: Rumyantseva N. А., Vanshteyn , B. G., & Skublov , S. G. (2021). Petrochemical features of tholeiites from the Shaka ridge (South Atlantic). Journal of Mining Institute, 248, 223-231. https://doi.org/10.31897/PMI.2021.2.6
Geology
  • Date submitted
    2021-01-28
  • Date accepted
    2021-04-21
  • Date published
    2021-06-24

Unusual metasomatites (phyolithites) in the Kolvitskiy gabbro-anorthosite rock mass: composition and structural position

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Complex mineralogical, geochemical, and geological-structural characteristics of a rare collection stone of violet color, phyolithite, in the southwestern part of the Kola Peninsula. This is a metasomatic rock formed under the conditions of brittle deformations on gabbro-anorthosites of the Paleoproterozoic Kolvitskiy rock mass. As a result of potassium metasomatosis, the plagioclase of the initial rocks was replaced by a fine-grained mica aggregate of muscovite-phengite composition with inclusions of Va-aluminoseladonite (up to 20-30 microns). Ba-aluminoseladonite contains 6.6-10.5 % by weight of BaO. Manganese is the only chromophore that accumulates in the rock during metasomatosis. It is manganese that provides the purple-violet color of pseudomorphs of mica according to anorthite. The phyolithites is depleted by REE and has a positive Eu-anomaly. The phyolithites are confined to the areas of fracturing of the north-eastern strike, located in the zone of dynamic influence of the north-western closure of the Onega-Kandalaksha rift of the Riphean age. Other formations (injection conglomerates and lamproites) are also associated with the formation of this structure, which owe their origin to an intense fluid flow.

How to cite: Terekhov , E. N., Makeev , A. B., Baluev , A. S., Konilov , A. N., & Van , K. V. (2021). Unusual metasomatites (phyolithites) in the Kolvitskiy gabbro-anorthosite rock mass: composition and structural position. Journal of Mining Institute, 248, 232-242. https://doi.org/10.31897/PMI.2021.2.7
Geology
  • Date submitted
    2020-05-14
  • Date accepted
    2020-10-05
  • Date published
    2020-11-24

Fahlbands of the Keret archipelago, White Sea: the composition of rocks and minerals, ore mineralization

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This paper presents a complex mineralogical and geochemical characteristic (based on SEM-EDS, ICP-MS analysis) of the fahlband rocks of the Kiv-Guba-Kartesh occurrence within the White Sea mobile belt (WSMB ). The term “fahlband” first appeared in the silver mines of Kongsberg in the 17th century. Now fahlbands are interlayers or lenses with sulfide impregnation, located in the host, usually metamorphic rock. The level of sulfide content in the rock exceed the typical accessory values, but at the same time be insufficient for massive ores . Fahlbands are weathered in a different way than the host rocks, so they are easily distinguished in outcrops due to their rusty-brown color. The studied rocks are amphibolites, differing from each other in garnet content and silicification degree. Ore mineralization is represented mainly by pyrrhotite and pyrite, and pyrrhotite grains are often replaced along the periphery by iron oxides and hydroxides, followed by pyrite overgrowth. At the same time, the rock contains practically unaltered pyrrhotite grains of irregular shape with fine exsolution structures composed of pentlandite, and individual pyrite grains with an increased Ni content (up to 5.4 wt.%). A relatively common mineral is chalcopyrite, which forms small grains, often trapped by pyrrhotite. We have also found single submicron sobolevskite and hedleyite grains. The REE composition of the fahlband rocks suggests that they are related to Archean metabasalts of the Seryakskaya and Loukhsko-Pisemskaya structures of the WSMB, rather than with metagabbroids and metaultrabasites common in the study area.

How to cite: Salimgaraeva , L. I., Skublov , S. G., Berezin , A. V., & Galankina , O. L. (2020). Fahlbands of the Keret archipelago, White Sea: the composition of rocks and minerals, ore mineralization. Journal of Mining Institute, 245, 513-521. https://doi.org/10.31897/PMI.2020.5.2
Geology
  • Date submitted
    2020-05-17
  • Date accepted
    2020-10-05
  • Date published
    2020-11-24

Geological structure of the northern part of the Kara Shelf near the Severnaya Zemlya archipelago according to recent studies

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Until recently, the North of the Kara Shelf was completely unexplored by seismic methods. Seismic and seismo-acoustic data that have appeared in recent years have made it possible to decipher features of the regional geological structure. This study solves the urgent problem of determining the prospects for the oil and gas potential of the North Kara sedimentary basin. The relevance of the research is associated with determining the prospects of the oil and gas potential of the North Kara sedimentary basin. The aim of the study is to clarify the age of the reflecting horizons using data on the geology of the island, as well as to determine the tectonic position of the sedimentary cover and basement structures in the north of the Kara shelf. The sedimentary cover is divided into three structural levels: Cambrian-Devonian, Middle Carboniferous-Cretaceous, Miocene-Quarter. The Cambrian-Devonian complex fills the deep troughs of the North Kara shelf. The most noticeable discontinuity is the base of Carboniferous-Permian rocks, lying on the eroded surface of folded Silurian-Devonian seismic complexes. The blanket-like plate part of the cover is composed of thin Carbon-Quarter complexes. The authors came to the conclusion that the fold structures of the Taimyr-Severozemelskiy fold belt gradually degenerate towards the Kara sedimentary basin and towards the continental slope of the Eurasian basin of the Arctic Ocean. A chain of narrow uplifts within the seabed relief, which correspond to narrow anticlines is traced to the West of the Severnaya Zemlya islands. Paleozoic rocks have subhorizontal bedding further to the West, within the Kara shelf. Mesozoic folding in the North of the Kara Sea is expressed exclusively in a weak activation of movements along faults. At the neotectonic stage, the shelf near Severnaya Zemlya was raised and the Mesozoic complexes were eroded. The modern seismic activity of the North Zemlya shelf is associated with the ongoing formation of the continental margin.

How to cite: Gusev , E. A., Krylov , A. A., Urvantsev , D. M., Goremykin , Y. V., & Krynitsky , P. I. (2020). Geological structure of the northern part of the Kara Shelf near the Severnaya Zemlya archipelago according to recent studies. Journal of Mining Institute, 245, 505-512. https://doi.org/10.31897/PMI.2020.5.1
Geology
  • Date submitted
    2020-06-13
  • Date accepted
    2020-06-14
  • Date published
    2020-06-30

Deep structure and geodynamic conditions of granitoid magmatism in the Eastern Russia

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We investigated the deep structure of the lithosphere and the geodynamic conditions of granitoid magmatism in the Eastern Russia within the borders of the Far Eastern Federal District. The relevance of the work is determined by the need to establish the geotectonic and geodynamic conditions of the granitoids petrogenesis and ore genesis in the Russian sector of the Pacific Ore Belt. The purpose of the article is to study the deep structure of the lithosphere and determine the geodynamic conditions of granitoid magmatism in the East of Russia. The author's data on the magmatism of ore regions, regional granitoids correlations, archive and published State Geological Map data, survey mapping, deep seismic sounding of the earth's crust, gravimetric survey, geothermal exploration, and other geophysical data obtained along geotraverses. The magma-controlling concentric geostructures of the region are distinguished and their deep structure is studied. The connection of plume magmatism with deep structures is traced. The chain of concentric geostructures of Eastern Russia controls the trans-regional zone of leucocratization of the earth's crust with a width of more than 1000 km, which includes the Far Eastern zone of Li-F granites. Magmacontrolling concentric geostructures are concentrated in three granitoid provinces: Novosibirsk-Chukotka, Yano-Kolyma, and Sikhote-Alin. The driving force of geodynamic processes and granitoid magmatism was mantle heat fluxes in the reduced zones of the lithospheric slab. The distribution of slab windows along the Pacific mobile belt's strike determines the location of concentric geostructures and the magnitude of granitoid magmatism in the regional provinces. Mantle diapirs are the cores of granitoid ore-magmatic systems. The location of the most important ore regions of the Eastern Russia in concentric geostructures surrounded by annuli of negative gravity anomalies is the most important regional metallogenic pattern reflecting the correlation between ore content and deep structure of the earth's crust.

How to cite: Alekseev , V. I. (2020). Deep structure and geodynamic conditions of granitoid magmatism in the Eastern Russia. Journal of Mining Institute, 243, 259. https://doi.org/10.31897/pmi.2020.3.259
Geology
  • Date submitted
    2020-05-06
  • Date accepted
    2020-05-24
  • Date published
    2020-06-30

Revisiting the evolution of deformation zones under platform conditions in the case study of the Kungur Ice Cave (Cis-Urals)

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Observations in mining tunnels and caves allow to identify composition and development specifics of fault structures under subsurface conditions at various stages of geological history. Basing on the existing formation model of Kungur Ice Cave karst system, author examines the transformations of deformation zones, occurring in the mass of interlaid sulfate and carbonate rocks under platform conditions. Morphologic specifics of vertical structures ­– organ pipes, developed within one of the gypsum-anhydrite units, are defined by evolution stages of disjunctive faults, penetrating the entire rock mass of the Ice Cave. Point infiltration of surface waters and formation of a single channel, where rock softening and taluses from overlapping deposits gradually occur, are currently considered to be the initiators of pipe formation. At a later stage a sink forms on the surface, increasing the amount of water coming to the karsting mass. However, the size of debris in the talus, incommensurate with the pipe head, rounded arches of separate pipes, fragments of feeder channels, characteristic for artesian conditions of underground water circulation, faceted rock debris from overlapping deposits, specifics of wall structure all define the priority of pipe formation over grottos and cave galleries. Plastic properties of gypsum sediments and processes of their hydration define secondary modifications of pipe walls up to complete filling of the voids and formation of secondary pillars with subsequent renewed formation of vertical channels – significantly smaller in diameter and formed by infiltration waters when subject to corrosion.

How to cite: Lavrova , N. V. (2020). Revisiting the evolution of deformation zones under platform conditions in the case study of the Kungur Ice Cave (Cis-Urals). Journal of Mining Institute, 243, 279. https://doi.org/10.31897/pmi.2020.3.279
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