Vol 64, No 4 (2019)


Nanoparticles and nanofluids in “water–rock” interactions

Alekseyev V.A.


A brief review of published papers was done in nanogeochemistry, a new field of geochemistry in which particles and fluids of small size (<100 nm) were investigated. They are different in properties from their larger analogs because of the greater contributions of their surface energy. Conditions, forms, and mechanisms of their formation and evolution were considered. Examples of size dependencies of nanoparticle and nanofluid properties (solubility and stability, melting temperature, inner pressure, surface charge and sorption, rates of evaporation, chemical reactions, and transport) were shown. Different influence of convex and concave surface on properties was noted. Widespread distribution of nanoparticles and nanofluids in nature provides their influence on various geochemical processes. Nanoparticles sorbs heavy metals and are the main form of their transport in natural waters. Nanofluids (nanopors) control the processes of diagenesis, metasomatic substitution and weathering, gas migration in shales. Even with a small content, nanoparticles can change behavior of macro systems dramatically. The main development directions of nanogeochemistry were summarized.

Геохимия. 2019;64(4):343-355
pages 343-355 views

Petrogenesis of the synplutonic high-magnesian porphyritic dykes from the mafic-granitoid plutons of the East-European Craton, Voronezh crystalline massif

Terentiev R.A.


This paper documents the data on high-Mg porphyrite dykes (PDs) from the mafic to felsic (~2.09 Ma) plutons of Elan complex (EC). The low-thickness (first centimeters) synplutonic dykes are characterized by sharp straight contacts without visible chilling zones, in contrast to the larger (up to 119 m) dykes that have gradual transitions. The dykes are fresh, porphyritic (bronzite, Al-enstatite, labradorite) and has fine-grained mainly quartzo-feldspathic (+biotite, sulfides, accessories, ±hypersthene) matrix. Based on geochemistry data the PDs are intermediate rocks (SiO2 = 58.9–60.3 wt. %) and plot into calc-alkaline series with high magnesian of whole rock (Mg# ~0.7) and felsic (68.9–70.2 wt. %) matrix (Mg# ~0.5). The PDs show differentiated rare-earth element patterns with negligible Eu anomalies. The bronzite phenocrysts varying sizes are characterized by block zoning and contain irregular inclusions of olivine (Mg# ~0.85), clinopyroxene (Mg# ~0.88), phlogopite (Mg# up to 0.94), labradorite, chrome spinel, graphite and sulfides. The Al-enstatite phenocrysts are practically sterile with respect to trace elements and mineral inclusions. The geochemical features as well as diffusion zones, reaction rims, and resorbed faces of the phenocrysts such as orthopyroxene and plagioclase indicate processes of recrystallization and/or partial dissolution of nonequilibrium crystals in the melt and indicate intratelluric nature of the dyke phenocrysts that cores are inherited from the EC derivatives/cumulate. The mineral thermometry estimates are: (1) the parent magma starting temperatures of 1200–1400 °С and (2) the EC crystallization temperatures 1080–1155 °С, (3) the PD emplacement temperatures 910–1070 °С. The petrogenetic model supposes the generation of EC high-temperature magmas similar to boninites from an upper metasomatized mantle. The melt is contaminated with continental crust lithologies. It implies the half-way evolved magma chamber in the crust. The PD melt, as a result of ending of the half-way magma chamber evolution, was emplaced into the still unheated EC plutons.

Геохимия. 2019;64(4):356-371
pages 356-371 views

Iron and sulfur isotope factors for pyrite from experimental gamma-resonant studies and heat capacity

Polyakov V.B., Osadchii E.G., Voronin M.V., Osadchii V.O., Sipavina L.V., Chareev D.A., Tyurin A.V., Gurevich V.M., Gavrichev K.S.


Pyrite Moessbauer spectra (FeS2) is measured in the temperature range from 90 to 295 K. The temperature dependence of the isomer shift is described by the Debye model with Moessbauer temperature θM=551.4 K. Using these results, we calculated the kinetic energy of thermal vibrations of the iron sublattice of pyrite and the iron β-factor for pyrite:

103lnβ57Fe/54Fe=(1.2665±0.0391)x–(0.4584±0.0283) × 10-2x2+(0.2581±0.0239) × 10-4x3; x=106/T 2 (K-2) The Moessbauer-derived iron β-factor for pyrite agrees well with results of ab initio calculations, 57Fe nuclear inelastic γ-resonant scattering synchrotron experiments and direct isotope exchange experiments between pyrite and Fe2+ dissolved in water.

Heat capacity of pyrite is measured at temperatures from 79 to 300 K. Its temperature dependence are described using the Thirring expansion. Based on this expansion, the kinetic energy of thermal vibrations of total crystalline lattice of pyrite is calculated. The kinetic energy of the thermal vibrations of the sulfur sublattice in pyrite is found by subtracting the iron sublattice kinetic energy from the total kinetic energy of pyrite crystalline lattice. Temperature dependence of 34S/32S β-factor for pyrite calculated from the kinetic energy of the sulfur sublattice is following:

103lnβ34Fe/32Fe=(1.7532±0.0623) x–(1.0470±0.0752) × 10-2 x2+(1.0424±0.1126) × 10-4 x3; x=106/T 2 (K-2)

This 34S/32S β-factor values exhibit a good agreement with of ab initio calculations and isotope-exchange experimental results in the pyrite-sphalerite-galenite system.

Геохимия. 2019;64(4):372-386
pages 372-386 views

Solubility of gold in the reduced carbonic fluid

Simakin A.G., Salova T.P., Gabitov R.I., Kogarko L.N., Tyutyunnik O.A.


The first experimental data on the gold solubility in the fluid with composition CO-CO2 and C-O-S with small water content at the pressure 200 MPa and temperature 950°С are reported. Solubility in the fluid C-O-S is about 27 ppm. Estimation of the solubility of gold in fluid CO-CO2 with 10–15 mol.% CO is less accurate: its value is at least 2–3 ppm, but it probably can reach 200–300 ppm. The high solubility of gold found in this work, and previously Pt (Simakin et al., 2016), in the reduced carbon dioxide can explain the formation of these noble metal ore occurrence in the Gluli intrusion (Polar Siberia) by their fluid extraction and re-deposition at temperatures below the solidus. The reducing of a substantially oxidized carbon dioxide fluid, established by mineralogical sensors, was probably caused by subsolidus oxidation of olivine.

Геохимия. 2019;64(4):387-394
pages 387-394 views

Mean contents of volatile components, major and trace elements in magmatic melts from main geodynamic settings of the earth. II. Silicic melts

Naumov V.B., Dorofeeva V.A., Girnis A.V., Yarmolyuk V.V.


As a continuation of our previous study, we estimated the mean contents of volatile, major, and trace components in silicic (>66 wt % SiO2) magmatic melts from main terrestrial geodynamic settings on the basis of our database, which includes (as of middle 2017) more than 1 500 000 determination of 75 elements in melt inclusions and quench glasses from rocks. Among the geodynamic settings are those related to subduction processes (III, island-arc zones originated on oceanic crust and IV, magmatic zones of active continental margins, where continental crust is involved in magma formation) and intracontinent rift and continental hot-spot regions (V). For each geodynamic setting, we calculated the mean contents of elements with confidence limits separately for melt inclusions and groundmass glasses and for the entire data set. Systematic differences were found between the mean compositions of melt inclusions and groundmass glasses from these geodynamic settings. Primitive mantle normalized spider diagrams were constructed for all geodynamic settings. Some ratios of elements and volatile components (H2O/Ce, K2O/Cl, La/Yb, Nb/U, Ba/Rb, Ce/ Pb, etc.) in silicic and mafic melts were compared. Variations in the ratios of various elements to Th, which is one of the most incompatible elements in silicic and mafic melts, were discussed.

Геохимия. 2019;64(4):395-408
pages 395-408 views

Geochemistry of carbonate rocks in early Precambrian and phanerozoic metamorphic complexes of East Siberia, north-west of Russia, Pamir

Levitskiy V.I., Reznitsky L.Z., Levitskiy I.V.


Geochemical study of carbonate rocks of Early-Precambrian and Phanerozoic metamorphic Complexes was carried out and their differences were revealed. Precambrian marbles and calciphyres studied in the Оnot Greenstone Belt, Kitoy and Sharyzhalgay granulitic Complexes Presayan uplift, Yenisei Series of the Angara-Kan Protrusion of the Siberian craton, the Belomorian and Lapland Complexes, North of the Pechenga Structure, Sortavala Suite of the Fennoscandian shield, Wakhan Complex of the Badakhshan Array; Phanerozoic – in Olkhon, Slyudyanka, Svyato nossky Complexes of the Baikal region, Boxon Series and Irkutnu Suite of the Eastern Sayan, Derbinsky Complex and Alchadur Suite of the Prisayan, Judin Suite and Panimba-Rybinsk Zone of the Yenisei Ridge, Muzkol Complex of the Eastern Pamirs. Precambrian carbonate rocks are enriched with Fe, Mn and depleted Sr, Ba in comparison with Phanerozoic rocks at a close low level of REE content. The Archean enrichment of Fe, Mn protoliths of marbles and calcifers is due to the dominance of basic and ultrabasic rocks in the feeding provinces. In the Paleoproterozoic, compared with the Phanerozoic, the proportion of Fe, Mn in carbonate rocks decreased, and Al, K, Ba, Sr have increased due to participation in occurrence their protoliths of the granite-metamorphic layer of the Earth. The distribution of petrogenic and rare elements in marbles and calcifirs is determined by the forms of their location: 1) in the isomorphic series of Ca-Mg carbonates with admixture of Fe, Mn, Ba, Sr, REE; 2) the presence of minerals Na, K, Ba, Sr in marbles; 3) location of thin (in marbles) and large (calcifications) fractions of minerals with iron, Mn Al, Ti, Zr, Cr, V, Ni, S. Performed paleoreconstruction behavior of REE in carbonate rocks in the Archean and Early-Paleoproterozoic dominated intracratonic shallow sea. Open oceans appeared at the turn of 2–1.9 billion years, but widespread development of carbonate rocks were in the Meso-Neoproterozoic and Phanerozoic. The revealed features are the basis of age-related paleoreconstructions of protoliths according to petrogeochemical characteristics of carbonate rocks of Precambrian and Phanerozoic metamorphic complexes.

Геохимия. 2019;64(4):409-426
pages 409-426 views

Methane and sulfide sulfur in the bottom sediments of lake Baikal

Gar’kusha D.N., Fedorov Y.A., Andreev Y.A., Tambieva N.S., Mikhailenko O.A.


The paper analyzes data on the distribution of methane and sulfide sulfur concentrations in the upper layer of the bottom sediments in different areas of Lake Baikal obtained during expeditions in 2014 and 2015. During the study, concentrations of methane and sulfide sulfur in lake sediments varied from <0.01 to 3.69 μg/g dry sediment (mean 0.34 μg/g) and from 0.002 to 0.830 mg/g dry sediment (mean 0.042 mg/g), respectively. The maximum concentrations of methane were typical of the Northern region, where the waters of the Upper Angara, Kichera rivers flow, and separate stations of profile along the estuary zone of the Selenga River, as well as stations located in the zone of underwater wastewater discharge of Baikalsk and the Baikal pulp and paper mill closed in 2013. A comparison of the distribution of methane and sulfide sulfur concentrations indicates an intense sulfate reduction at the stations with the highest methane concentrations, which suggests the conjugate processes of their generation. Variations of methane and sulfide sulfur concentrations in the studied upper layers of Lake Baikal sediments are caused by the differences in the anthropogenic impact and also by the variability of sedimentation conditions that determine the grain size composition and the content of organic matter, and, as a consequence, the intensity of methanogenesis and sulfate reduction.

Геохимия. 2019;64(4):427-439
pages 427-439 views

Radioecological situation in the area of monazite placer in South Yakutia

Sobakin P.I., Gerasimov Y.R., Perk A.A.


The results of radioecological investigation of the territory of Vasilyevka monazite placer in South Yakutia are given. The processes of deposit development causing radioactive pollution of the territory are described. They induce high exposure rates of gamma-radiation on ground surface and higher concentration of thorium in soil and plants. Identified areas of natural concentrations of thorium in the alluvial sediments, creating the anomalously high values of dose rate of gamma radiation on the surface and is exceeding 9–23 times of the normal natural radiation background. The extent of wind dispersion of thorium from pollution source was estimated along its vertical distribution in a soil profile of podbours.

Геохимия. 2019;64(4):440-448
pages 440-448 views

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