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Scientific articles
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Typomorphism of hypogene accessory mineralsof
the Vymsky Horst structure (Middle Timan).
Olivine, pyropes
Yu. V. Glukhov, B. A. Makeev, M. Yu. Sokerin
DOI: 10.19110/geov.2020.10.1
The results of mineralogical study of pyropes and olivine from the Vymskaya horst-anticline structure (Kyvvozh goldbearing placer field, Middle Timan), that found during the heavy mineral concentrate sampling, are presented. Optical microscopy, electron microprobe, and scanning electron microscope were used in the research. High preservation of the endogenous surface of some pyrope individuals and olivine is demonstrated, indicating the closeness of their magmatic sources. The studied pyrope garnets belong to the lherzolite paragenesis of mantle minerals. Microinclusions of chrome spinels and orthopyroxene (enstatite) were found in some garnet grains. Abundant microinclusions of the high-pressure and high-temperature titanium-zirconium mineral srilankite (the first find on Timan) were found in one pyrope individual from the headstream of Belaya Kedva river. Investigated pyropes are characterized by compositions, which are identical to the ones for pyrope garnets from Umba kimberlite field (Middle Timan). It seems that magmatic rocks from the Umba pipes field are analogues of parent rock sources of pyropes from Kyvvozh goldbearing area and (or) themselves are sources for these pyropes.
Keywords: diamondferousity, kimberlite indicator minerals, pyrope, olivine, Vol’sko-Vymsky ridge, Middle Timan.
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3—11
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Mineral sediments of the Kholodnyy grotto cave
(Bzyb Gorge, Abkhazia) and d13C carbon
and d18O oxygenisotope composition of karstogenic carbonates
O. Ya. Chervyatsova, S. S. Potapov, L. V. Leonova,
J. Baker, R. S. Dbar
DOI: 10.19110/geov.2020.10.2
The article is devoted to the results of the study of the mineral and isotopic composition of speleothems of the of the Kholodnyy Grotto cavein the Bzyb gorge of Abkhazia. The cavity was mapped and various types of secondary mineral deposits were recorded. The following mineral formations (speleothems) have been established in the cave: Mondmilch, corallites, guhrs, carbonate breccias, biogenic phosphates. Attention is drawn to the abundance of allogeneic mineral inclusions in drip calcite associated with the weathering products of igneous rocks (zircon, potassium feldspar, ilmenite, rutile, monazite, apatite). The source of these minerals is presumably the weathering crust of the Middle Jurassic volcanics.
The oxygen isotope composition of all studied carbonates reflects the participation of meteoric waters. Moreover, the isotopic composition of carbon is subject to significant variations associated with kinetic fractionation (CO2 degassing). Based on the results of petrographic and isotopic studies, an attempt was made to typify speleothems according to the nature of their feeding and the characteristics of crystallization.
Also, the cave revealed phosphate mineralization in the form of dark brown thin-layered crusts of hydroxylapatite, formed in place of old guano deposits.
Keywords: carbonate and phosphate mineralization, calcite, hydroxylapatite, bat guano, isotopic composition, KholodnyyGrotto cave, Bzyb gorge, Abkhazia.
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12—21
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Amino acids as biomarkers of phase
сompositionof gallstones
O. Ye. Amosova, Е. V. Mashina, S. N. Shanina
DOI: 10.19110/geov.2020.10.3
Gallstone disease (cholelithiasis) remains one of the most common gastroenterological diseases worldwide. The formation of gallstones has not been fully studied due to the latent course of the initial stage of gallstone disease. The composition of gallstones is diverse. Among the substances present in gallstones, the least studied is the protein component, the structural units of which are amino acids. In this connection, the main goal of the study was to identify patterns of changes in the amino acid composition of gallstones of various phase compositions. The objects of the study were 23 samples of gallstones belonging to residents of the Komi Republic. Data analysis was carried out by statistical one-dimensional and multidimensional methods. The statistical analysis, used in this work to study pathogenic formations in the human body, revealed qualitatively new, previously unremarked features of the amino acid composition of gallstones, which indicated the difference in the protein component and its relationship with the phase composition of gallstones.
According to the results of cluster analysis by the contents of all amino acids, the studied gallstones were grouped into three different phase compositions of the type — cholesterol, cholesterol with a mineral component, and pigment. The Mann-Whitney and Student’s criteria established that all three types of gallstones were statistically significantly (p <0.05) pairwise different in the contents of alanine, valine, isoleucine, leucine, proline, phenylalanine, aspartic and glutamic acid. The lowest contents of the amino acids were determined in cholesterol gallstones, the highest — in pigment ones. The multidimensional method of classification trees also revealed individual amino acids phenylalanine, proline, leucine, according to which gallstones of different phase compositions were clearly separated by type. Based on the results obtained by statistical methods, special attention should be paid to Phenylalanine acid most clearly compared gallstones of different phase composition in comparison with others.
The established relationships can be used to predict the type of cholelithiasis, to solve the problem of gallstones formation and metaphylaxis.
Keywords: Mann-Whitney test, Student’s unpaired t-test, cluster analysis, classification trees, gallstones, amino acids.
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22—30
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A new approach to the calculation of the greatest
debitof suspended mud flood load considering influence
of main natural factors
(by the sample of riversof Minor Caucauses)
J. H. Mamedov, Z. R. Rasulov
DOI: 10.19110/geov.2020.10.4
The work is devoted to the methodology for calculating the highest flow rates of suspended sediment mudflows of the rivers of the Minor Caucasus. The research materials were the data from stationary observations of the highest suspended sediment load presented by the Department of Hydrometeorology under the Ministry of Natural Resources of the Republic of Azerbaijan until 2000 and data from expeditionary operations until 2016. For extension of the series of the highest suspended sediment load rates, the relationships Qmax. = f (Rvax.) from 2000 to 2015. The parameters of physical and geographic factors influencing the high flow rates of suspended sediments are analyzed separately and in a complex. As main natural factors that determine the volume of mudflow sediment load, the values of the highest water discharge, the coefficient of natural regulation of river flow and forest cover of the catchment area were taken. The study resulted in the methodology for calculating the largest flow rate of suspended sediment. It mostly reflects conditions for the formation of mudflows and has a calculation error of ± 25%. Recommended formulas can be used to study and describe parameters of mudflows of unexplored rivers of the Minor Caucasus.
Keywords:mudflows, natural regulation of river runoff, alluviums, alluvial cone, highest flow rates of suspended sediments, mudflows.
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31—37
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Modeling petrographic structures
Yu. L. Voytekhovsky, A. A. Zakharova
DOI: 10.19110/geov.2020.10.5
The article describes a technique for 2D modeling of structures and textures of bimineral rocks in terms of the probabilities of binary intergranular contacts. It is shown that typical petrographic structures (disseminated, chained, poikilitic, porphyric) and textures (massive, banded, schlieren) regularly fill the barycentric diagram (pii, pjj, pij) of contact probabilities. These structures and textures are correlated with the Hardy-Weinberg equilibrium. The problems of modeling polymineral petrographic structures and textures are discussed. A new type of structural diagrams is suggested. The article is dedicated to the memory of Dr. Sci. Yu. A. Tkachev — a well-known Russian specialist in the field of modeling the structures of sedimentary rocks.
Keywords:crystalline rock, petrographic structures: disseminated, chained, poikilitic, porphyric; petrographic textures: massive, banded, schlieren.
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38—42
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Chronicle, events, facts
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Yu. A. Tkachev's Science Heritage. In memory of scientist (1935—2020)
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43—44 |
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