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Date submitted2022-11-29
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Date accepted2023-03-02
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Date published2023-10-27
New data on the composition of growth medium of fibrous diamonds from the placers of the Western Urals
This article presents the results of studying microinclusions of fluids/melts in diamonds from the placers of the Krasnovishersky District (western slope of the Middle/Northern Urals), which make it possible to establish the evolution of diamond-forming media in the subcontinental lithospheric mantle of the eastern margin of the East European craton. Impurity composition of the studied crystals reveals three different types of diamonds, the formation of which was associated with separated metasomatic events. Microinclusions in B-type diamonds containing A and B nitrogen defects reflect an older metasomatic stage characterized by the leading role of silicic and low-Mg carbonatitic fluids/melts. The second stage is associated with the growth of A-type diamonds containing nitrogen exclusively in the form of A-centers. At this stage, the formation of diamonds was related with low-Mg carbonatitic media, more enriched in MgO, CaO, CO2, and Na2O compared to B-type diamonds. The third stage probably preceded the eruption of the transporting mantle melt and led to the formation of C-type diamond containing A and C nitrogen defect centers and microinclusions of silicic to low-Mg carbonatitic composition. The recorded trend in the evolution of diamond-forming fluids/melts is directed towards more carbonatitic compositions. Fluids/melts are probably sourced from eclogitic and pyroxenitic mantle substrates.
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Date submitted2022-04-15
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Date accepted2022-11-17
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Date published2023-04-25
Uranium in man-made carbonates on the territory of Ufa
The paper presents the results of analyzing uranium content in man-made carbonates (scale crusts) on the territory of Ufa based on examination of 42 samples. The median uranium content in the investigated samples stands at 1.44 mg/kg, which is significantly lower than the background values (scales from the Lake Baikal water, a clarke of sedimentary carbonate rocks) and data on other settlements of the Republic of Bashkortostan. Low values of uranium content are probably associated with the effects of the three leading factors, i.e. specific subsurface geology of the territory (gypsum, limestone); types of water supply; water treatment processes for the centralized type of water supply. Spatial distribution of uranium in man-made carbonates is characterized with uniformity, which is disturbed in two cases, i.e. a change of the water supply type (from centralized to individual); and material of the vessels used for boiling the water. No significant differences were detected when comparing samples of man-made carbonates associated with different sources of water supply (the bucket and infiltration types of water intake) and the types of household filters.
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Date submitted2022-04-29
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Date accepted2022-07-21
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Date published2022-11-10
Deep structure, tectonics and geodynamics of the Sea of Okhotsk region and structures of its folded frame
The use of the zonal-block model of the earth's crust for the construction of regional tectonic schemes and sections of the earth's crust based on a complex of geological and geophysical data makes it possible to consider the resulting maps and sections as tectonic models. The main elements of such models are blocks with an ancient continental base and interblock zones formed by complexes of island arcs, an accretionary prism, or oceanic crust. The developed geotectonic model of the Sea of Okhotsk region reflects the features of the deep structure, tectonics, and geodynamics. The Cimmerian Novosibirsk-Chukotka, Verkhoyansk-Kolyma, Kolyma-Omolon, and Amur folded regions and the Alpides of the Koryak-Kamchatka and Sakhalin-Sikhote-Alin folded regions are developed along the northern, western, and southern boundaries of the Sea of Okhotsk megablock with a continental crust type. From the east, the megablock is limited by oceanic basins and island arcs.
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Date submitted2022-02-26
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Date accepted2022-04-27
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Date published2022-07-26
Type intrusive series of the Far East belt of lithium-fluoric granites and its ore content
- Authors:
- Viktor I. Alekseev
The evolution and ore content of granitoid magmatism in the Far East belt of lithium-fluoric granites lying in the Russian sector of the Pacific ore belt have been studied. Correlation of intrusive series in the Novosibirsk-Chukotka, Yana-Kolyma and Sikhote-Alin granitoid provinces of the studied region allowed to establish the unity of composition, evolution, and ore content of the Late Mesozoic granitoid magmatism. On this basis, a model of the type potentially ore-bearing intrusive series of the Far East belt of lithium-fluoric granites has been developed: complexes of diorite-granodiorite and granite formations → complexes of monzonite-syenite and granite-granosyenite formations → complexes of leucogranite and alaskite formations → complexes of rare-metal lithium-fluoric granite formation. The main petrological trend in granitoid evolution is increasing silicic acidity, alkalinity, and rare-metal-tin specialization along with decreasing size and number of intrusions. At the end of the intrusive series, small complexes of rare-metal lithium-fluoric granites form. The main metallogenic trend in granitoid evolution is an increasing ore-generating potential of intrusive complexes with their growing differentiation. Ore-bearing rare-metal-granite magmatism of the Russian Far East developed in the Late Cretaceous and determined the formation of large tungsten-tin deposits with associated rare metals: Ta, Nb, Li, Cs, Rb, In in areas with completed intrusive series. Incompleteness of granitoid series of the Pacific ore belt should be considered as a potential sign of blind rare-metal-tin mineralization. The Far East belt of lithium-fluoric granites extends to the Chinese and Alaskan sectors of the Pacific belt, which allows the model of the type ore-bearing intrusive series to be used in the territories adjacent to Russia.
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Date submitted2022-05-04
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Date accepted2022-06-15
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Date published2022-07-26
Prospecting models of primary diamond deposits of the north of the East European Platform
As a result of a comprehensive study of the geological structure and diamond presense of the northern part of the East European Platform, generalization of the data accumulated by various organizations in the USSR, the Russian Federation, and other states, three main prospecting models of primary diamond deposits have been identified and characterized: Karelian, Finnish, and Arkhangelsk. Geological, structural, mineralogical, and petrographic criteria of local prediction, as well as the features of the response of kimberlite and lamproite bodies in dispersion haloes and geophysical fields, are considered using known examples, including data on the developed M.V.Lomonosov and V.P.Grib mines. It is shown that the most complicated prospecting environments occur in the covered areas of the Russian Plate, where, in some cases, the primary diamond-bearing rocks are similar in their petrophysical properties to the host formations. The buried dispersion haloes of kimberlite minerals in the continental Carboniferous and Quaternary deposits are traced at a short distance from the sources. Differences in the prospecting features of magnesian (Lomonosov mine) and ferromagnesian (Grib mine) kimberlites are also shown. Conclusions about the diamond potential of the model objects of various types are given in this paper.
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Date submitted2020-08-03
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Date accepted2020-12-13
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Date published2021-06-24
Tectonic and magmatic factors of Li-F granites localization of the East of Russia
- Authors:
- Viktor I. Alekseev
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.
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Date submitted2020-06-13
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Date accepted2020-06-14
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Date published2020-06-30
Deep structure and geodynamic conditions of granitoid magmatism in the Eastern Russia
- Authors:
- Viktor I. Alekseev
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.
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Date submitted2018-08-30
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Date accepted2018-11-06
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Date published2019-02-22
Tourmaline as an ondicator of tin occurrences of cassiterite-quartz and cassiterite-silicate formations (a case study of the Verkhneurmiysky ore cluster, Far East)
- Authors:
- V. I. Alekseev
- Yu. B. Marin
The research focused on the composition of tourmaline from tin ore deposits and ore occurrences within the Verkhneurmiysky ore cluster in the Amur region. The aim of the study is to determine the indicative signs of tourmaline from cassiterite-quartz and cassiterite-silicate formations. This research is based on the materials of a long-term study of the mineralogy of the Far East deposits, conducted at the Mining University under the scientific supervision of Professor Yu.B.Marin. The relevance of the study involves predicting of tin and associated mineralization. For the first time, SIMS and Mössbauer spectroscopy were used to study tourmaline from this region. We identified the typomorphic characteristics of the tourmaline composition, which are proposed to be used as indicators of tin-ore deposits. Typomorphic characteristics of tourmaline from cassiterite-quartz formation: schorl (Mg/(Mg + Fe) = 0.06) with a high content of Al and K; Fe 3+ /(Fe 3+ + Fe 2+ ) = 0.03; Z Fe 3+ = 1 %; impurities: Nb, LREE (La, Ce, Pr), Be, Bi, F, Li, and Mn; LREE content > 9 ppm; positive Gd anomaly. Typomorphic characteristics of tourmaline from cassiterite-silicate formation: schorl-dravite (Mg/(Mg + Fe) = 0.22) with a high Ca content; Fe 3+ / (Fe 3+ + Fe 2+ ) = 0.17; Z Fe 3+ = 9 %; impurities: Zr, Y, Cr, V, Sn, In, Pb, W, Mo, Ti, HREE, Eu, Sr, Sb, and Sc; the content of Y is > 2 ppm, of HREE is > 3 ppm, Eu is > 0.1 ppm.
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Date submitted2018-06-27
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Date accepted2018-09-18
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Date published2018-12-21
Migration forms of chemical elements in the intrusive rocks of the Eastern Desert (El Sela area, Egypt)
- Authors:
- M. M. Ghoneim
- E. G. Panova
In the Egypt's Eastern Desert intrusive rocks with U-REE mineralization (two-mica granites, microgranites, dolerites, and bostonites) are developed. We estimated the content of chemical elements in reference samples of intrusive rocks and also in their water-soluble (colloid-salt) fraction. This fraction is water-extracted from the rock under certain conditions. The rock sample and its colloid-salt fraction are analyzed using ICP-MS. The chemical characteristic of the extracted fraction reflects the mobile migrating part of the chemical elements in the composition of the rocks. Comparison of the obtained data allows us to estimate the share of migrating and weakly migrating elements.
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Date submitted2015-10-08
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Date accepted2015-12-11
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Date published2016-08-22
Rare metal granites in the structures of the Russian sector of Pacific ore belt
- Authors:
- V. I. Alekseev
Data are presented on the geology of areas of rare metal granites proliferation in the Russian sector of the Pacific Ore Belt that make one take a fresh look at the East Asian granitoid area to update its metallogeny. History is reviewed of studying rare metal granites of the Russian Far East. As a rule, these are found in the vicinity of major tungsten-stanniferous ore deposits, except much later than discovering the former, at the stages of their assessment and survey. Rare earth granites are usually missed by the geologists during the early stages of regional geological surveys due to their small size, weak eroding and external similarity with earlier granites. Using the examples of the Central Polousny, Badzhal and Kuyviveem-Pyrekakay regions the structural and geological conditions are characterized of localization of rare metal granites. Comparative analysis of geological situations made it possible to formulate the areal character of manifestation of rare metal granites; their confinedness to late Mesozoic orogenic arched uplifts of bogen structures above deep granitoid batholiths; positioning in the areas where longitudinal and transversal deep laying faults cross; gravitation to the environs of pre-Cambrian median masses.
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Date submitted2015-07-21
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Date accepted2015-09-24
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Date published2016-02-24
Tectonic development and granitoid magmatism of Northeast Asia in the late mesozoic
- Authors:
- V. I. Alekseev
The history of tectonic development and granitoid magmatism of Northeast Asia in the late Mesozoic is considered. The variety of tectonic situations and granitoid magmatism are favorable circumstances for the solution of many fundamental problems in geology, but tectono-magmatic division into districts is complicated owing to variability of the composition and the structure of the Earth’s crust. A rational approach to the tectonic division into districts of a region by the research of granitoid magmatism based on determining consolidated crust blocks with various tectonic history is offered. Pre-mesozoic and mesozoic structures of the Far East, among which primary and superimposed on the Precambrian and Paleozoic base Verkhoyansk orogeny prevails, are determined. The conclusion on the important role of middle massifs and passive margins with a thin Riphean-Paleozoic cover in geodynamic development of the Far East is drawn. The mesozoic activization of ancient structures along with young granitoid magmatism is established. The driving force of the Pacific ore belt granitization was the interaction of the Paleo-Pacific Plate and plates in Northeast Asia in the middle-late Mesozoic. The history of regional tectogenesis and granitoid magmatism in the late Triassic–Eocene (230-33,7 million years) taking into account the latest geodynamic concepts is tracked. The place in tectonic history of the Asian continental margin of plutonic and volcanic-plutonic belts is determined. Four stages of tectonomagmatic development of the Far East are established: the Jurassic and the early Cretaceous collisional, the early Cretaceous upsubduction, the late Cretaceous upsubduction-transform and the late Cretaceous–Paleogene rift-related.
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Date submitted2009-10-12
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Date accepted2009-12-26
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Date published2010-09-22
Methods and techniques for control of rockburst-hazard in underground mining at ore mines of the Far-East district
An assessment is given to the present-day state of control of dynamic rock pressure manifestations in the rockburst-hazardous ore mines of the Far-East district. Consideration is given to the used methods and facilities for control of rock pressure and the ways for their improvement . Basic foundations of methodical approaches to the assessment of geomechanical state of rock mass by data of geoacoustic control are considered.
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Date submitted2008-10-21
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Date accepted2008-12-25
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Date published2009-12-11
Comparative analysis of spiriferida complexes of the frasnian stage in the south of Novaya Zemlya and one-aged complexes of East-European platform and other districts
- Authors:
- D. V. Bezgodova
The Article contains a brief characteristic of spiriferida (brachiopod) complexes spread in the Frasnian sediments in the South of Novaya Zemlya, and their comparison with one-aged complexes of several regions of East-European platform, such as Main Devonian field, Central districts, the Volga-Urals region, South Timan, south-western districts and also outlying districts of the Kuznetsk coal basin and North-West of Russia.
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Date submitted2008-10-10
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Date accepted2008-12-23
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Date published2009-12-11
Modern methods of hydrogeological investigations in terms of prospecting of titanium-magnetic iron deposit «South-East Gremiakha»
The paper considers the contemporary level of hydrogeological investigations during prospecting of deposits. It is suggested to use numerical modeling, sensors, computer programs for pumping tests. These methods are illustrated by prospecting of the South-East Gremiakha deposit.