Journal articles: 'Polymineralic rocks'

1

Handy, Mark R. "The solid-state flow of polymineralic rocks." Journal of Geophysical Research 95, B6 (1990): 8647. http://dx.doi.org/10.1029/jb095ib06p08647.

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Jordan, Peter. "The rheology of polymineralic rocks — an approach." Geologische Rundschau 77, no. 1 (February 1988): 285–94. http://dx.doi.org/10.1007/bf01848690.

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Takeda, Yoshi-Taka. "Flow in rocks modelled as multiphase continua: application to polymineralic rocks." Journal of Structural Geology 20, no. 11 (November 1998): 1569–78. http://dx.doi.org/10.1016/s0191-8141(98)00043-1.

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Linckens, Jolien, Marco Herwegh, and Othmar Müntener. "Linking temperature estimates and microstructures in deformed polymineralic mantle rocks." Geochemistry, Geophysics, Geosystems 12, no. 8 (August 2011): n/a. http://dx.doi.org/10.1029/2011gc003536.

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Schofield, P. F., S. J. Covey-Crump, I. C. Stretton, M. R. Daymond, K. S. Knight, and R. F. Holloway. "Using neutron diffraction measurements to characterize the mechanical properties of polymineralic rocks." Mineralogical Magazine 67, no. 5 (October 2003): 967–87. http://dx.doi.org/10.1180/0026461036750138.

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AbstractConventional experiments designed to investigate the mechanical properties of polycrystalline geological materials are generally restricted to measurements of whole-rock properties. However, when comparing the measurements with theoretical models, it is frequently essential to understand how the deformation is accommodated at the grain-scale. This is particularly true for polymineralic rocks because in this case most theories express the whole-rock properties as some function of the properties of their constituent minerals, and hence the contribution which each phase makes to those properties must be measured if the theories are to be fully assessed. The penetrating nature of neutrons offers a method of addressing this problem. By performing deformation experiments in the neutron beam-line and collecting neutron diffraction patterns at different applied loads, the lattice parameters of all the mineral phases present may be determined as a function of load. The elastic strain experienced by each phase is then easily determined. Moreover, the strain in different lattice directions is also obtained. From this information a wide range of problems relevant for the characterization of the elastic and plastic deformation behaviour of polymineralic geological materials can be explored. An experimental technique for carrying out such experiments is described, and its validity is demonstrated by showing that the results obtained from deforming an elastically isotropic olivine + magnesiowüstite sample agree, to within very tight bounds, with the behaviour predicted by theory for elastically isotropic composites.

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Hunter, Nicholas J. R., R. F. Weinberg, C. J. L. Wilson, V. Luzin, and S. Misra. "Quartz deformation across interlayered monomineralic and polymineralic rocks: A comparative analysis." Journal of Structural Geology 119 (February 2019): 118–34. http://dx.doi.org/10.1016/j.jsg.2018.12.005.

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Henry, Bernard. "Modelling the relationship between magnetic fabric and strain in polymineralic rocks." Physics of the Earth and Planetary Interiors 70, no. 3-4 (March 1992): 214–18. http://dx.doi.org/10.1016/0031-9201(92)90185-x.

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Larre, Chloé, Yann Morizet, Catherine Guillot-Deudon, Fabien Baron, and Nicolas Mangold. "Quantitative Raman calibration of sulfate-bearing polymineralic mixtures: a S quantification in sedimentary rocks on Mars." Mineralogical Magazine 83, no. 1 (September 14, 2018): 57–69. http://dx.doi.org/10.1180/mgm.2018.147.

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AbstractThe NASA 2020 Mars mission is a Curiosity-type rover whose objective is to improve the knowledge of the geological and climatic evolution of Mars and to collect rock samples for return to Earth. The new rover has a payload of seven instruments including the SuperCam instrument which consists of four tools including a Raman spectrometer. This Raman device will be non-destructive and will analyse the surface remotely in order to determine the mineralogy of rocks and, by extent, to detect and quantify major elements such as sulfur. Sulfur has been detected as sulfate (Ca,Mg,Fe-sulfates) in sedimentary rocks. This element is difficult to quantify using the laser ablation tool of the ChemCam instrument on-board the Curiosity rover.We propose a Raman calibration to constrain the sulfur abundance in polymineralic mixtures. We acquired Raman signatures on binary and ternary mechanical mixtures containing Ca and Mg sulfates, mixed with natural silicate minerals supposed to be relevant to basaltic-sedimentary rocks at the surface of Mars: olivine, clinopyroxene, orthopyroxene and plagioclase. Using the Voigt function to process the Raman spectra from samples extracted from our mixtures allows us to calculate the initial proportions of our preparations of Ca and Mg sulfates. From these simulations, calibration equations have been provided allowing us to determine sulfate proportions (CaSO4 and MgSO4) in a mixture with basaltic minerals. With the presented calibration, S can be quantified at a lower limit of 0.7 wt.% in Martian soil.

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Mikhailova, Julia A., Yakov A. Pakhomovsky, Ekaterina A. Selivanova, and Alena A. Kompanchenko. "Polymineralic Inclusions in Loparite-(Ce) from the Lovozero Alkaline Massif (Kola Peninsula, Russia): Hydrothermal Association in Miniature." Minerals 13, no. 6 (May 23, 2023): 715. http://dx.doi.org/10.3390/min13060715.

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Polymineralic inclusions in loparite-(Ce) in alkaline rocks from the Lovozero massif (Russia) were investigated using electron microprobe analysis, Raman spectroscopy, and X-ray diffraction. A total of 21 mineral species and two groups of minerals (pyrochlore- and labuntsovite-group minerals) were found in these inclusions. Minerals in loparite-hosted inclusions can be divided into two groups: (1) minerals found typically in rocks bearing loparite-(Ce) grains (groundmass minerals) such as aegirine, magnesio-arfvedsonite, potassic feldspar, albite, fluorapatite, etc.; and (2) minerals that were not found in the rock outside of the loparite-(Ce) grains. The latter include lorenzenite, labuntsovite-group minerals, minerals of the neptunite–manganoneptunite series, vinogradovite, catapleiite, fluorite, britholite-(Ce), barylite, genthelvite, and barite, found in the studied samples exclusively inside loparite-(Ce) crystals. The minerals of the second group are typical hydrothermal minerals. We assume that the skeletal crystals of loparite-(Ce), when growing, captured both co-crystallizing minerals and small drops of the mineral-forming solution. Such drops subsequently crystallized within the loparite-(Ce), resulting in the formation of a hydrothermal mineral association.

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Uzel, Jessica, Yves Lagabrielle, Serge Fourcade, Christian Chopin, Pierre Monchoux, Camille Clerc, and Marc Poujol. "The sapphirine-bearing rocks in contact with the Lherz peridotite body: New mineralogical data, age and interpretation." BSGF - Earth Sciences Bulletin 191 (2020): 5. http://dx.doi.org/10.1051/bsgf/2019015.

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Sapphirine-bearing rocks are described in the Aulus Basin (Ariège, France) in a contact zone between the Lherz peridotitic body and Mesozoic metasediments which underwent the Pyrenean Cretaceous high-temperature, low-pressure metamorphic event (Monchoux, 1970, 1972a, 1972b). Sapphirine crystals occur in layered clastic deposits characterized by an uncommon suite of Al-Mg-rich minerals. A detailed petrographic study of sixteen samples representative of the diversity of the Lherz sapphirine-bearing rocks is presented. These rocks include breccias and microbreccias with various compositions. Some samples are composed of polymineralic clasts and isolated minerals that derive from regionally well-known protoliths such as ultramafic rocks, meta-ophites, “micaceous hornfels”, and very scarce Paleozoic basement rocks. Nevertheless, a large portion of the sapphirine-bearing clastic suite is composed of mono- and polymineralic debris that derive from unknown protolith(s). We define a "sapphirine-bearing mineral suite” (SBMS) composed of monomineralic debris including: sapphirine + enstatite + aluminous spinel + Mg-amphiboles + Ca-amphiboles + kornerupine + accessory minerals (apatite, diopside, rutile, serpentine, smectite, tourmaline, vermiculite and a white mica). We highlight the dominance of metamorphic Keuper clastic materials in the studied rocks and the presence of inclusions of anhydrite and F-, Cl-, Sr-rich apatite in minerals of the Al-Mg-rich suite. The brecciated texture and the presence of unequivocal sedimentary features suggest that the sapphirine-bearing rocks were mechanically disaggregated and then experienced winnowing in underwater conditions with poor mixing between the different sources. We measured U-Pb rutile age data in order to provide constraints on the age of (one of) the protolith(s) of those clastic deposits. The obtained age (98.6 + 1.2 Ma) is interpreted as the age of metamorphism of this protolith of the SBMS. Previous works interpreted the Lherz sapphirine-bearing rocks as crustal protoliths modified at depth along the contact with the ultramafic rocks of the Lherz body during their ascent towards shallower depths. These new data imply: (i) an Upper Triassic to Lower Jurassic origin for the main protolith of the sapphirine-bearing rocks; (ii) the metamorphism of this protolith along an active hot crust–mantle detachment during Cenomanian times with the involvement of metasomatic, brine-type fluids; and (iii) its brecciation during the exhumation of the material due to the evolution of the detachment, followed by subsequent sedimentary reworking of the metamorphic material.

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Cruciani, Gabriele, Marcello Franceschelli, Hans-Joachim Massonne, Giovanni Musumeci, and Massimo Scodina. "Garnet-Rich Veins in an Ultrabasic Amphibolite from NE Sardinia, Italy: An Example of Vein Mineralogical Re-Equilibration during the Exhumation of a Granulite Terrane." Geosciences 10, no. 9 (August 31, 2020): 344. http://dx.doi.org/10.3390/geosciences10090344.

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A complex system of mono- and polymineralic centimeter-thick veins occurs within the ultrabasic amphibolites of Montigiu Nieddu hill in northeastern Sardinia, and they are filled with garnet, amphibole, chlorite, and epidote. Some garnet-rich veins are margined by an amphibole layer at the interface with the host rock and/or show replacement of epidote concentrated in the vein core. Together with homogeneous matrix garnet (Grt1), millimetric, euhedral, and strongly zoned garnet porphyroblasts occur within these veins. The estimated pressure–temperature conditions (P = 1.0–1.7 GPa, T = 650–750 °C) for the formation of Grt1 match the metamorphic peak and early exhumation derived previously for the host rocks and confirm that the garnet veins also formed under high-pressure (HP) conditions. The igneous protolith of the host rocks experienced HP metamorphism in a subduction zone and underwent exhumation in an exhumation channel. The vein system in the ultrabasic amphibolites formed by cyclic hydrofracturing as rapid and transient events such as crack-seal veining. The growth of multiple vein-filling mineral assemblages indicates the formation of separate vein-producing cycles.

12

Wheeler, John. "Importance of pressure solution and coble creep in the deformation of polymineralic rocks." Journal of Geophysical Research 97, B4 (1992): 4579. http://dx.doi.org/10.1029/91jb02476.

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13

Herwegh, Marco, Alfons Berger, and Andreas Ebert. "Grain coarsening maps: A new tool to predict microfabric evolution of polymineralic rocks." Geology 33, no. 10 (2005): 801. http://dx.doi.org/10.1130/g21789.1.

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Herwegh, M., and A. Jenni. "Granular flow in polymineralic rocks bearing sheet silicates: new evidence from natural examples." Tectonophysics 332, no. 3 (March 2001): 309–20. http://dx.doi.org/10.1016/s0040-1951(00)00288-2.

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VOYTEKHOVSKY, Yury, and Alena ZAKHAROVA. "Petrographic structures and Hardy – Weinberg equilibrium." Journal of Mining Institute 242 (June 10, 2020): 133. http://dx.doi.org/10.31897/pmi.2020.2.133.

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The article is devoted to the most narrative side of modern petrography – the definition, classification and nomenclature of petrographic structures. We suggest a mathematical formalism using the theory of quadratic forms (with a promising extension to algebraic forms of the third and fourth orders) and statistics of binary (ternary and quaternary, respectively) intergranular contacts in a polymineralic rock. It allows constructing a complete classification of petrographic structures with boundaries corresponding to Hardy – Weinberg equilibria. The algebraic expression of the petrographic structure is the canonical diagonal form of the symmetric probability matrix of binary intergranular contacts in the rock. Each petrographic structure is uniquely associated with a structural indicatrix – the central quadratic surface in n-dimensional space, where n is the number of minerals composing the rock. Structural indicatrix is an analogue of the conoscopic figure used for optical recognition of minerals. We show that the continuity of changes in the organization of rocks (i.e., the probabilities of various intergranular contacts) does not contradict a dramatic change in the structure of the rocks, neighboring within the classification. This solved the problem, which seemed insoluble to A.Harker and E.S.Fedorov. The technique was used to describe the granite structures of the Salminsky pluton (Karelia) and the Akzhailau massif (Kazakhstan) and is potentially applicable for the monotonous strata differentiation, section correlation, or wherever an unambiguous, reproducible determination of petrographic structures is needed. An important promising task of the method is to extract rocks' genetic information from the obtained data.

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Herwegh, M., J. Linckens, A. Ebert, A. Berger, and S. H. Brodhag. "The role of second phases for controlling microstructural evolution in polymineralic rocks: A review." Journal of Structural Geology 33, no. 12 (December 2011): 1728–50. http://dx.doi.org/10.1016/j.jsg.2011.08.011.

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Mansard, Nicolas, Holger Stünitz, Hugues Raimbourg, Jacques Précigout, Alexis Plunder, and Lucille Nègre. "Relationship between microstructures and resistance in mafic assemblages that deform and transform." Solid Earth 11, no. 6 (November 18, 2020): 2141–67. http://dx.doi.org/10.5194/se-11-2141-2020.

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Abstract. Syn-kinematic mineral reactions play an important role for the mechanical properties of polymineralic rocks. Mineral reactions (i.e., nucleation of new phases) may lead to grain size reduction, producing fine-grained polymineralic mixtures, which have a strongly reduced viscosity because of the activation of grain-size-sensitive deformation processes. In order to study the effect of deformation–reaction feedback(s) on sample strength, we performed rock deformation experiments on “wet” assemblages of mafic compositions in a Griggs-type solid-medium deformation apparatus. Shear strain was applied at constant strain rate (10−5 s−1) and constant confining pressure (1 GPa) with temperatures ranging from 800 to 900 ∘C. At low shear strain, the assemblages that react faster are significantly weaker than the ones that react more slowly, demonstrating that reaction progress has a first-order control on rock strength. With increasing strain, we document two contrasting microstructural scenarios: (1) the development of a single throughgoing high-strain zone of well-mixed, fine-grained aggregates, associated with a significant weakening after peak stress, and (2) the development of partially connected, nearly monomineralic shear bands without major weakening. The lack of weakening is caused by the absence of interconnected well-mixed aggregates of fine-grained reaction products. The nature of the reaction products, and hence the intensity of the mechanical weakening, is controlled by the microstructures of the reaction products to a large extent, e.g., the amount of amphibole and the phase distribution of reaction products. The samples with the largest amount of amphibole exhibit a larger grain size and show less weakening. In addition to their implications for the deformation of natural shear zones, our findings demonstrate that the feedback between deformation and mineral reactions can lead to large differences in mechanical strength, even at relatively small initial differences in mineral composition.

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Handy, Mark R. "Correction and addition [to “The solid-state flow of polymineralic rocks” by Mark R. Handy]." Journal of Geophysical Research: Solid Earth 97, B2 (February 10, 1992): 1897–99. http://dx.doi.org/10.1029/91jb02203.

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Covey-Crump, S. J., P. F. Schofield, I. C. Stretton, M. R. Daymond, K. S. Knight, and J. Tant. "Monitoring in situ stress/strain behaviour during plastic yielding in polymineralic rocks using neutron diffraction." Journal of Structural Geology 47 (February 2013): 36–51. http://dx.doi.org/10.1016/j.jsg.2012.10.003.

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Brodhag, Sabine H., Marco Herwegh, and Alfons Berger. "Grain coarsening in polymineralic contact metamorphic carbonate rocks: The role of different physical interactions during coarsening." Journal of Structural Geology 33, no. 4 (April 2011): 698–712. http://dx.doi.org/10.1016/j.jsg.2010.12.003.

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21

Reid, Arch M., and Anton P. le Roex. "Kaersutite-Bearing Xenoliths and Megacrysts in Volcanic Rocks from the Funk Seamount in the Southwest Indian Ocean." Mineralogical Magazine 52, no. 366 (June 1988): 359–70. http://dx.doi.org/10.1180/minmag.1988.052.366.07.

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AbstractEight samples (seven volcanic rocks and one quartz sandstone) have been dredged from the Funk Seamount, 60 km NW of Marion Island in the southwest Indian Ocean (lat. 46° 15′S, long. 37° 20′ E). The volcanic rocks are fine-grained vesicular basanitoids and glass-rich volcanic breccias geochemically similar to the Marion Island lavas. Lavas and breccias contain a suite of megacryst minerals and of small polymineralic xenoliths, in both of which kaersutite is a prominent constituent.The megacryst suite comprises large unzoned single grains of kaersutite, plagioclase, pyroxene, magnetite and ilmenite, all showing textural evidence of resorption/reaction with the basanitoid host. The megacrysts have a limited range of compositions except for the plagioclase which ranges from oligoclase to labradorite.The small (2 mm to ∼ 3 cm) xenoliths are mostly two-pyroxene amphibole assemblages with or without olivine, magnetite, ilmenite, plagioclase and apatite. The xenoliths show some evidence of reaction with the basanitoid host and most have undergone recrystallization and/or localised decompression melting.Xenolith and megacryst assemblages are interpreted as being associated with the formation and partial crystallization of a hydrous basanitoid melt at depth.

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Czaplińska, Daria, Sandra Piazolo, and Ivan Zibra. "The influence of phase and grain size distribution on the dynamics of strain localization in polymineralic rocks." Journal of Structural Geology 72 (March 2015): 15–32. http://dx.doi.org/10.1016/j.jsg.2015.01.001.

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Ji, Shaocheng, Qin Wang, and Bin Xia. "P-wave velocities of polymineralic rocks: comparison of theory and experiment and test of elastic mixture rules." Tectonophysics 366, no. 3-4 (May 2003): 165–85. http://dx.doi.org/10.1016/s0040-1951(03)00094-5.

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Rakhimov, Ildar, Evgenii Pushkarev, and Irina Gottman. "Chromite Paleoplacer in the Permian Sediments at the East Edge of the East European Platform: Composition and Potential Sources." Minerals 11, no. 7 (June 27, 2021): 691. http://dx.doi.org/10.3390/min11070691.

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A chromite occurrence called the Sabantuy paleoplacer was discovered in the Southern Pre-Ural region, at the east edge of the East-European Platform in the transitional zone to the Ural Foredeep. A ca. 1 m-thick chromite-bearing horizon is traced at a depth of 0.7–1.5 m from the earth’s surface for the area of ca. 15,000 m2. The chromspinel content in sandstones reaches 30–35%, maximum values of Cr2O3 are 16–17 wt.%. The grain size of detrital chromspinel ranges from 0.15 to 0.25 mm. Subangular octahedral crystals dominate; rounded grains and debris are rare. The composition of detrital chromspinel varies widely and is constrained by the substitution of Al3+ and Cr3+, Fe2+ and Mg2+ cations. Chemically, low-Al (Al2O3 = 12 wt.%) and high-Cr (Cr2O3 = 52–56 wt.%) chromspinel prevail. The compositional analysis using discrimination diagrams showed that most chromites correspond to mantle peridotites of subduction settings. Volcanic rocks could be an additional source for detrital chromites. It is confirmed by compositions of monomineralic, polymineralic and melt inclusions in chromspinels. The presented data indicates that ophiolite peridotites and related chromite ore associated with oceanic and island-arc volcanic rocks, widespread in the Ural orogen, could be the main sources of the detrital chromspinel of the Sabantuy paleoplacer.

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Romeo, I., R. Capote, R. Lunar, and N. Cayzer. "Polymineralic orientation analysis of magmatic rocks using Electron Back-Scatter Diffraction: Implications for igneous fabric origin and evolution." Tectonophysics 444, no. 1-4 (November 2007): 45–62. http://dx.doi.org/10.1016/j.tecto.2007.08.006.

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Mansard, Nicolas, Holger Stünitz, Hugues Raimbourg, and Jacques Précigout. "The role of deformation-reaction interactions to localize strain in polymineralic rocks: Insights from experimentally deformed plagioclase-pyroxene assemblages." Journal of Structural Geology 134 (May 2020): 104008. http://dx.doi.org/10.1016/j.jsg.2020.104008.

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Wiesman, Harison S., Mark E. Zimmerman, and David L. Kohlstedt. "Laboratory investigation of mechanisms for phase mixing in olivine + ferropericlase aggregates." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, no. 2132 (October 2018): 20170417. http://dx.doi.org/10.1098/rsta.2017.0417.

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To investigate the role of grain boundary pinning and the mechanisms by which phase mixing occurs during deformation of polymineralic rocks, we conducted high-strain torsion experiments on samples consisting of olivine plus 30 vol% ferropericlase. Experiments were performed in a gas-medium deformation apparatus at 1524 K and 300 MPa. Samples were deformed to outer radius shear strains of up to γ ( R ) = 14.1. The value of the stress exponent and the small grain sizes of our samples indicate that our two-phase material deformed by dislocation-accommodated grain boundary sliding. In samples deformed to 1 < γ < 7, elongated clusters of ferropericlase grains form thin layers in the olivine matrix, and small grains of ferropericlase appear at olivine grain boundaries and three- and four-grain junctions. By γ ≈ 14, a well-distributed mixture of small ferropericlase grains among the olivine grains developed. Microstructures exhibit similarities to both mechanical and chemical models proposed to describe the processes leading to phase mixing. Our results provide evidence for grain size reduction during phase mixing that results in a grain size significantly smaller than the value predicted by the single-phase recrystallization piezometer for olivine. Thus, phase mixing provides a mechanism for the persistent weakening of rocks that is important for developing and maintaining shear zones necessary for plate tectonics. This article is part of a discussion meeting issue ‘Earth dynamics and the development of plate tectonics'.

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Peverelli, Veronica, Alfons Berger, Martin Wille, Thomas Pettke, Pierre Lanari, Igor Maria Villa, and Marco Herwegh. "Epidote dissolution–precipitation during viscous granular flow: a micro-chemical and isotope study." Solid Earth 13, no. 11 (November 22, 2022): 1803–21. http://dx.doi.org/10.5194/se-13-1803-2022.

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Abstract. Deformation of polymineralic aggregates can be accommodated by viscous granular flow, a process mediated by the interplay among intracrystalline plasticity and dissolution–precipitation, each active in specific minerals under given P–T conditions. Some rock-forming minerals like quartz and feldspars have been intensively studied in terms of deformation processes. Instead, the deformation behavior of epidote and its role during viscous granular flow is not well investigated, although this mineral is ubiquitous in granitic rocks deforming under greenschist-facies conditions. In this contribution, we provide microstructural and geochemical evidence for the occurrence of dissolution–precipitation of epidote during deformation of an epidote–quartz vein. The main part of the vein is deformed, producing a fold, which is visible due to relicts of primary-growth layering inside the vein. The deformation mechanisms active during deformation include dynamic recrystallization of quartz by subgrain rotation recrystallization, producing grain size reduction in the primary vein quartz. Recrystallization occurs contemporaneously with dissolution and (re)precipitation of epidote and quartz grain boundary sliding, leading to a combined process described as viscous granular flow. The combination of grain boundary sliding and dissolution locally and repeatedly produces creep cavities. These represent not only loci for nucleation of new epidote grains at the expense of dissolved ones, but they also allow fluid-mediated transport of elements. The same trace element patterns between old epidote relicts and newly formed grains, with much narrower variability in the latter, indicate a process of chemical homogenization. The nature of the fluid that mediates deformation is investigated using Pb–Sr isotope data of epidote, which suggest that deformation is assisted by internally recycled fluids with the addition of a syn-kinematic external fluid component.

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Jordan, Sherri L., Aphrodite Indares, and Greg Dunning. "Partial melting of metapelites in the Gagnon terrane below the high-pressure belt in the Manicouagan area (Grenville Province): pressure–temperature (P–T) and U–Pb age constraints and implications." Canadian Journal of Earth Sciences 43, no. 9 (September 1, 2006): 1309–29. http://dx.doi.org/10.1139/e06-038.

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Metapelites of the parautochthonous Gagnon terrane at the footwall of the high-pressure (high-P) belt in the Manicouagan area (central Grenville Province) preserve an impressive textural record of partial melting reactions, mainly in polymineralic inclusions within garnet. The dominant textures were developed within the pressure–temperature (P–T) field of the continuous dehydration melting reaction biotite + kyanite (or sillimanite) + plagioclase + quartz = garnet + K-feldspar + melt, with sillimanite instead of kyanite in the southern part of the footwall. Inferred P–T paths have a hair-pin form in the range of 750–850 °C and 1000–1500 MPa for the kyanite-bearing rocks. Monazite crystallization ages are consistently late Grenvillian, either 995 or 985 Ma, and one sample contains monazite of both ages. Two of these samples also contain inherited monazite with ages of 1738 ± 5 and 1719 ± 30 Ma, indicative of an earlier metamorphic event. Tonalite and diorite from the same area yield Archean zircon crystallization ages and titanite ages of 961 ± 3 and 956 ± 4 Ma, the youngest in the Manicouagan region. The late Grenvillian metamorphism was of comparable intensity but ~50 Ma younger than in the overlying high-P belt in this area and therefore seems to be unrelated to the emplacement of the latter over the Parautochthonous Belt, as previously suggested. Rather, this younger metamorphism suggests a reactivation of the footwall by underthrusting of the Gagnon terrane during the waning stages of convergence, and a link with a major coeval post-tectonic thermal event farther south in the hinterland.

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FEINBURG, GRIGORY, and KONSTANTIN CHERNY. "PHYSICAL PROPERTIES OF SALT ROCKS, WHICH ARE FORMING SPECIFIC PARAMETERS OF AIR ENVIRONMENT." News of the Tula state university. Sciences of Earth 1, no. 1 (2023): 67–80. http://dx.doi.org/10.46689/2218-5194-2023-1-1-67-80.

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The article discusses the main physical and chemical properties of salt rocks - alkali metal chlorides of sodium, potassium, magnesium - halite, sylvinite, carnallite, which form the specific parameters of the air environment of rock-salt and potash mines, including underground speleohospitals, as well as special salt rooms - "salt caves" or speleoclimatic chambers used for therapeutic and recreational purposes. The data of long-term field observations by the authors for slow current (for visual observation and instrumental fixation) natural phenomena - the interfacial interaction of moist air with the polymineral salt surface of natural rocks are presented.

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Kotelnikov, A. R., G. M. Akhmedzhanova, N. I. Suk, K. V. Martynov, O. T. Gavlina, and V. A. Suvorova. "Synthesis of minerals and polymineral matrixes for immobilization of radioactive wastes elements." Геохимия 64, no. 10 (November 19, 2019): 1047–63. http://dx.doi.org/10.31857/s0016-752564101047-1063.

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For the development of methods for the disposal of radioactive waste in the rocks of the earths crust, the concept of phase and chemical correspondence in the system of matrix material ― host rock has been proposed. This principle allows directional synthesis of certain mineral matrices. Matrix materials were experimentally synthesized ― solid solutions of minerals for immobilization of alkaline, alkaline-earth, rare-earth elements ― radionuclides. The properties of a number of solid solutions of minerals are investigated. The possibilities of processing graphite into stable matrices are studied. Methods of fixation and separation of noble metals (components of radioactive waste) and halides (Br, I) have been developed. The problems of processing glass matrix minerals (borosilicate and aluminophosphate glasses) into stable crystalline matrix materials are considered. Methods for processing glass matrices into mineral matrix materials are presented.

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Shevko, A. Ya, V. M. Kalugin, M. P. Gora, and N. S. Karmanov. "The first discovery of oxyborates in the rocks of the Norilsk-1 intrusion (northwest of the Siberian platform)." Доклады Академии наук 488, no. 2 (September 24, 2019): 189–92. http://dx.doi.org/10.31857/s0869-56524882189-192.

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We found five boron minerals in the taxitic gabbrodolerites near the upper contact of the Norilsk-1 ore-bearing intrusion. These are kotoite Mg3(BO3)2, suanite Mg2B2O5, warwickite (Mg,Ti,Fe,Cr,Al)2O(BO3), ludwigite (Mg)2Fe3+O2(BO3), and azoproite (Mg,Fe2+)2(Fe3+,Ti,Mg)O2(BO3). This is the first discovery of oxyborate minerals in the Norilsk province. They form monomineral and polymineral inclusions in olivine grains from the recrystallized areas of the taxitic intrusive rocks. Boron minerals arose at the late stage of the magma crystallization or just after that as a result of the interaction of the rock with the boron-bearing fluid containing in the ore-bearing magma. Presence of the micro inclusions of the oxyborates as well as higher boron content in rocks can be used as a criterion for searching of the Pt-Cu-Ni-bearing intrusions in the Norilsk province.

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Harris, D. L., and B. G. Lottermoser. "Phosphate stabilization of polyminerallic mine wastes." Mineralogical Magazine 70, no. 1 (February 2006): 1–13. http://dx.doi.org/10.1180/0026461067010309.

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AbstractPolyminerallic, sulphidic mine wastes were treated with KH2PO4-H2O2 solutions to determine whether the formation of solid phosphate coatings inhibits sulphide oxidation and metal and metalloid mobility. The waste rocks were metal (PbZnCu) and metalloid (AsSb) rich and consisted of major quartz, dickite, illite and sulphide minerals (e.g. galena, chalcopyrite, tetrahedrite, sphalerite, pyrite, arsenopyrite) as well as minor to trace amounts of pre- and post-mining oxidation products (e.g. oxides, hydroxides, arsenates and sulphates). Scanning electron microscopy observations of the waste material treated with KH2PO4-H2O2 solutions showed that metal, metal-alkali and alkali phosphate precipitates formed and coatings developed on all sulphides (with the exception of tetrahedrite). The abundance of phosphate phases was dependant on the availability of metal and alkali cations in solution. In turn, the release of cations was dependent on the amount of sulphide oxidation induced during the experiment or the presence of soluble oxidation products. Lead and to a lesser degree Cu and Zn phosphate coatings remained stable during H2O2 leaching, preventing acid generation and metal release. In contrast, the lack of phosphate coating on tetrahedrite and arsenopyrite allowed oxidation and leaching of As and Sb to proceed and mobilized As and Sb did not form phosphate phases. As a result, As and Sb displayed the greatest release from the coated waste. Thus, the application of KH2PO4-H2O2 solutions to partly oxidized, polyminerallic mine wastes suppresses sulphide oxidation and is most effective in inhibiting Pb (Cu and Zn) release. However, the technique appears ineffective in preventing metalloid (As, Sb) leaching from tetrahedrite- and arsenopyrite-bearing wastes.

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Voytekhovsky, Yu L., and A. A. Zakharova. "Modeling petrographic structures." Vestnik of Geosciences 10 (2020): 38–42. http://dx.doi.org/10.19110/geov.2020.10.5.

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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.

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Polyansky, O. P., I. I. Likhanov, A. V. Babichev, P. S. Kozlov, S. V. Zinoviev, and V. G. Sverdlova. "Fault Tectonites of the Yenisei Shear Zone (Yenisei Ridge): Evidence and Thermomechanical Numerical Model of Generation of Tectonic Overpressure." Петрология 32, no. 1 (June 7, 2024): 19–45. http://dx.doi.org/10.31857/s0869590324010036.

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Based on the proposed numerical model of the stress-strain state of polymineral rocks, which describes the formation of blastomylonites in the Yenisei Regional Shear Zone (PRSZ) in the Yenisei Ridge, the possibility of local tectonic overpressure exceeding the lithostatic pressure in rocks subjected to shear deformations is shown. For tectonites of the southern (Angara-Kan block) and northern (Isakovka terrane and Garevka complex) segments of the PRSZ, estimates of the maximum overpressure were obtained from 2–3 to 4–5 kbar, which range from 25 to 50% of the lithostatic pressure. It is shown that excess pressures can be preserved in a local volume on a geological time scale sufficient for their fixation in metamorphic minerals. Model values of overlithostatic pressure in garnet-amphibole tectonites and geobarometric estimates of peak values during stress metamorphism allow us to offer new evidence of pressure inhomogeneity in natural mineral associations. Using the results of numerical modeling for the evolution of fault metabasite blastomylonites, it was established that the overpressure at the stage of syn-deformation metamorphism in the shear zone are possible at temperatures up to 600–650°C and not reaching 800°C; the presence of fluid or partial melt prevents the occurrence of overpressure. The amount of excess pressure due to shear stresses depends on the mineral composition and structure of the rock.

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Barkov, A. Y., N. D. Tolstykh, R. F. Martin, N. Tamura, Chi Ma, and A. A. Nikiforov. "Kuvaevite, Ir5Ni10S16, a New Mineral Species, Its Associations and Genetic Features, from the Sisim River Placer Zone, Eastern Sayans." Russian Geology and Geophysics 63, no. 12 (December 1, 2022): 1373–87. http://dx.doi.org/10.2113/rgg20224455.

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Abstract —Kuvaevite, ((Ir,Rh)5(Ni,Fe,Cu)10S16), forms small grains (up to 20 µm across) in globular inclusions hosted by grains of Os–Ir–(Ru) alloys (up to 0.5 mm) in ore occurrences along the Ko River in the Sisim placer zone, Eastern Sayans. Rh-bearing pentlandite or oberthürite (or both), the minerals of the laurite-erlichmanite series and Pt–(Pd)–Fe alloys are the main associated minerals. Kuvaevite is gray to brownish gray in color in reflected light. Its bireflectance is weak to absent. It is slightly pleochroic in gray to light brown shades, and slightly anisotropic, from gray to light yellow shades. Its calculated density is 6.37 g/cm3. According to results of microprobe analyses (n = 3) carried out using wavelength-dispersive spectrometry, WDS, the composition of kuvaevite is: Cu 5.94 (4.39–6.89), Ni 13.95 (13.80–14.24), Fe 10.95 (10.18–11.97), Co 0.07 (0.06–0.10), Ir 32.38 (32.19–32.73), Rh 7.27 (7.22–7.31), Pt 1.91 (1.67–2.06), Os 0.05 (0–0.09), Ru 0.05 (0.04–0.05), S 27.06 (26.77–27.41), total 99.63 wt.%. The empirical formulae calculated using the mean results of analyses are: (Ir3.22Rh1.35Pt0.19Ru0.01Os0.01)Σ4.78(Ni4.54Fe3.75Cu1.79Co0.02)Σ10.10S16.13 (WDS) and (Ir3.23Rh1.43Pt0.25)Σ4.91(Ni4.49Fe3.57Cu1.86Co0.06)Σ9.98S16.11 (SEM/EDS; n = 56). These are based on a total of 31 atoms according to structural data obtained for torryweiserite, the rhodium-dominant analogue. Kuvaevite forms solid-solution series with torryweiserite, tamuraite and ferrotorryweiserite, all these being isostructural. The symmetry of kuvaevite was determined using the synchrotron Laue microdiffraction; the results are in good agreement with the trigonal crystal system and give the following unit-cell parameters: a = 7.079(5) Å, c = 34.344(12) Å, V = 1490(2) Å3; Z = 3. The ratio c/a is 4.852. The probable space-group, R3m (#166), is based on structural results for torryweiserite. The strongest eight reflections in the X-ray diffraction pattern derived from the microdiffraction study [d in Å(hkl) (I)], are the following: 3.0530(201)(43), 3.0103(216)(100), 2.9962(1010)(53), 2.7991(205)(50), 2.4946(208)(31), 1.9208(3110)(41), 1.7697(410)(73), 1.7582(2016)(66). The results of the electron backscatter diffraction study (EBSD) of two kuvaevite crystals are well–indexed based on the R3m space group. Kuvaevite and related sulfides significantly vary in composition in the Ko River placer, in the entire Sisim zone, and in some other ore occurrences worldwide. Associations of platinum-group minerals observed in ore occurrences at Ko River and in the Sisim zone seem to be genetically related to bedrock zones of chromite-bearing ultramafic rocks (serpentinites) of the Lysanskiy complex. Kuvaevite and other minerals present in the polymineralic inclusions, hosted by Os–Ir–(Ru) alloys, formed from droplets of residual melt. This melt accumulated the “incompatible” elements, which could not be incorporated into the structure of the host alloy, including lithophile elements, chalcogens (S, Te), semimetals (As, Sb, Bi), base metals (Fe, Ni, Cu), as well as relatively low-temperature PGE species (Pt, Pd) and Rh. There are local data on metastable crystallization and undercooling of the silicate melt, as well as effective differentiation and fractionation of S and ore components during the crystallization of these inclusions. Kuvaevite is named after O.M. Kuvaev (1934–1975), a prominent geologist, geophysicist and writer.

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Pearson, A., F. Heidelbach, and H. R. Wenk. "Texture Analysis of Quartz in a Granite Mylonite by EBSP-Orientation Imaging Microscopy." Textures and Microstructures 29, no. 3-4 (January 1, 1997): 185–99. http://dx.doi.org/10.1155/tsm.29.185.

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The crystallographic preferred orientation (texture) of the quartz phase in a mylonitic leucogranite from the Santa Rosa mylonite zone was investigated using automated analysis of electron backscattering patterns (EBSP) in the scanning electron microscope (SEM). The separation of the quartz diffraction patterns from patterns of other constituents (feldspar, mica, etc.) in this polymineralic rock was achieved using an image quality parameter. The quartz phase displays a texture typical for high temperature mylonites (c-axis maximum in the intermediate strain direction). The misorientation distribution between next neighbors is dominated by Dauphiné twins.

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Guo, Mingzhe, Zengmin Lun, Bing Zhou, Lianguo Wang, and Huiqing Liu. "Experimental Study on Water-Rock Interaction Characteristics of Unconsolidated Sandstone during CO2 Multicomponent Thermal Fluid Injection." Geofluids 2023 (April 25, 2023): 1–8. http://dx.doi.org/10.1155/2023/2197400.

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According to the reservoir characteristics and the current situation of CO2 utilization during thermal recovery in an unconsolidated sandstone heavy oil reservoir, the mechanism and law of porosity and permeability change in an unconsolidated sandstone heavy oil reservoir during CO2+steam and CO2+steam+ sodium alpha-olefin sulfonate (AOS) injection were studied by combining a static monomineral water-rock reaction and a dynamic polymineral sand pack displacement experiment. In the static water-rock reaction between CO2 and monomineral of reservoir rock, the dissolution degree of monomineral at 200°C is greater than that at 100°C and 300°C, and the order of mineral dissolution is illite, montmorillonite, kaolinite, and quartz. Besides, the dissolution rate of single rock minerals decreased significantly in the system of CO2 with AOS. In the polymineral sand pack displacement experiment, the porosity gradually decreases by CO2 multicomponent thermal fluid, and the permeability first decreases and then increases by CO2 multicomponent thermal fluid, but the permeability change is only about 0.5% by CO2+steam+ AOS, which is mainly attributed to the adsorption of AOS on the rock surface, and it is confirmed in the infrared spectrum of unconsolidated sand after displacement. This also shows that CO2+steam+AOS can stabilize the rock skeleton structure of the reservoir and prevent the deterioration of heterogeneity in the subsequent development of thermal recovery of heavy oil reservoirs; therefore, the CO2 multicomponent thermal fluid with chemical agents can improve the damage of a single CO2 thermal fluid to the reservoir.

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Alekseev, V. I., and Yu B. Marin. "COLUMBITE-TANTALITE OF THE KESTER DEPOSIT (EASTERN YAKUTIA)." Tikhookeanskaya Geologiya 41, no. 2 (2022): 109–20. http://dx.doi.org/10.30911/0207-4028-2022-41-2-109-120.

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Three mineral species of the columbite group were installed at the Kester deposit (Eastern Yakutia): columbite-(Fe), columbite-(Mn) and tantalite-(Mn), which are part of rare-metal granites and ongonites, albitites and greisens. Columbite-(Mn) prevails: Ta/(Ta + Nb) = 0.30, Mn/(Mn + Fe) = 0.64. The generalized formula for the columbite-tantalite of deposit is (Mn0.61Fe0.34)0.95(Nb1.37Ta0.58Ti0.04W0.03Sn0.01)2.03O6. Columbite tantalite combine the polymineral individuals with concentric growth zonality (from core to rim): columbite-(Fe) → columbite-(Mn) → tantalite-(Mn) + uranmicrolite → columbite-(Mn). A typomorphic impurity in the columbite of Kester deposit – WO3: an average of 2.67 % (apfu 0.04); maximum 7.12 % (apfu 0.11). Isomorphic substitution of cations in position B is assumed according to the scheme: 2(Nb,Ta)5+ ↔ W6+ + Ti4+. Typomorphic impurity in tantalite – SnO2: on average 1.01 % (apfu 0.03); maximum 3.74 % (apfu 0.21). Paragenesis of columbite-group minerals includes: albite, topaz, lepidolite, Nb-Ta-containing cassiterite, wolframoixiolite, wolframite, U-Hf-containing zircon, struverite. The evolution of columbite-tantalite of the Kester deposit is accompanied by an increase in the relations of Ta/Nb, Mn/Fe, Sn/W, expressed in the change of columbite by tantalite both in the process of formation of ore-bearing rocks and in the series of these rocks: rare-metal granites → albitites → greisens. Fluctuation limits of ratios Ta/(Ta + Nb) 0.07–0.74, Mn/(Mn + Fe) 0.16–0.96. The diversity and evolution of the columbite-group minerals of Kester deposit indicate their belonging to the rare-metal ore- magmatic system, which includes ore-bearing rare-metal granites, albitites and greisens. The presence of the small intrusions of rare-metal granites and ongonites in the area of the deposit allows predicting the discovery of new objects of bed-rock and placer columbite-tantalite mineralization.

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Murzin, V. V., D. A. Varlamov, E. S. Karaseva, and A. Yu Kisin. "Mineralogy and Conditions of Formation Genesis of Aggregates of Natural and Sulfide Minerals of the Poldnevskoe Demantoid Deposit (Middle Urals)." Геология рудных месторождений 65, no. 6 (November 1, 2023): 528–50. http://dx.doi.org/10.31857/s0016777023060060.

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Polymineral aggregates of rounded shapes (“nodules”) composed of native and sulfide minerals of Cu, Ni, Fe, Ag, and other elements from vein magnetite–calcite–chrysotile rocks with jewelry demantoid in the Korkodinskoe hypermafic massif are described. A common feature of the six identified types of native sulfide nodules, composed of native copper, heazlewoodite, pentlandite, cuprite, and other native sulfide minerals, is their spheroidal shape, which makes them similar to individual grains of other gangue minerals (calcite, magnetite, etc.). In heazlewoodite–pentlandite nodules, specific symplectites of mercuric silver and nickel copper in heazlewoodite, as well as awaruite in Co–pentlandite, were found. The matching set of ore minerals in the host serpentinite vein mass (native copper, mercuric silver, heazlewoodite, pentlandite, awaruite) and nodules from the vein material indicates their genetic connection and the conjugation of demantoid mineralization with the evolving processes of serpentinization. It was established that the nodules formed at temperatures below 380°C under reducing conditions at very low sulfur fugacity values (10–17–10–27 bar) and oxygen (10–30 bar at 200°C to 10–21 bar at 350°C). For heazlewoodite–pentlandite nodules, such conditions persisted throughout the entire time of their formation, while, for other nodules, the reducing conditions of early parageneses were replaced by oxidative conditions in late parageneses, which is recorded by the replacement of native copper with cuprite. It is assumed that the features of the morphology and structure of native sulfide nodules and the presence of symplectite intergrowths of ore minerals in them are associated with specific conditions created during the decompression of the crust-mantle mixture rising to the surface in the fault zone. The source of the metals was a deep, high-temperature fluid interacting with mafic and ultramafic rocks under reducing conditions at a low water-to-rock ratio.

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Shamanina, A., Arkadiy Ayzenshtadt, V. Kononova, and V. Danilov. "ESTIMATION OF THE EFFICIENCY OF MECHANICAL ACTIVATION OF SILICA-CONTAINING ROCKS." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 6, no. 5 (May 18, 2021): 19–27. http://dx.doi.org/10.34031/2071-7318-2021-6-5-19-27.

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Rocks of various chemical and mineralogical composition are widely used as raw materials in the construction materials industry. At the same time, preliminary mechanical activation of mineral raw materials to a finely dispersed state contributes to a change in the energy potential of the system and affects the tendency of the surface of a finely dispersed system to transformations. Studies of the physicochemical activity of mechanically activated rocks allow to determine the rational areas of use of mineral components. The paper presents the results of evaluating the efficiency of mechanical activation of silica-containing raw materials by the values of surface activity (ks), defined as the ratio of the value of the free surface energy to the specific mass energy of atomization. Fine powders are obtained by grinding in a planetary ball mill to a different specific surface area of quartz sand (1200 – 3000 m2/kg) and polymineral sand (700 – 1335 m2/kg). The presence of a functional dependence of the surface activity on the time parameters of mechanical activation of the studied rocks is shown. The mechanical activation of the feedstock at the optimal time of its grinding makes it possible to achieve a given value of the surface activity. It is recommended to use the ks parameter as a criterion for assessing the efficiency of the process of mechanical activation of silica-containing rocks

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Wang, Zidong, Qian Zhang, Jianlin Liu, and Li-Yun Fu. "Effective moduli of rocks predicted by the Kuster–Toksöz and Mori–Tanaka models." Journal of Geophysics and Engineering 18, no. 4 (August 2021): 539–57. http://dx.doi.org/10.1093/jge/gxab034.

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Abstract Natural rocks are polymineral composites with complex microstructures. Such strong heterogeneities significantly affect the estimation of effective moduli by some theoretical models. First, we have compared the effective moduli of isotropic rocks predicted by the Kuster–Toksöz (KT) model and the Mori–Tanaka (MT) model. The widely used KT model only has finite precision in many cases because of its assumption that is restricted to the first-order scattering approximation. However, the MT model based on the Eshelby tensor in mesomechanics has the advantage of predicting effective moduli of rocks, especially when the volume fraction of embedded inclusions is sufficiently large. In addition, the MT model can be used to predict the effective modulus of anisotropic rocks, but the KT model cannot. For a certain kind of shale or tight sandstones, which are viewed as isotropic composites, both the models work well. For the medium containing spherical pores, both the models produce the same results, whereas for ellipsoidal pores the MT model is more accurate than the KT model, validated by the finite element simulations. In what follows, the applicable ranges of simplified formulas for pores with needle, coin and disk shapes, widely used in engineering, are quantitatively given based on the comparison with the results according to the reduced ellipsoidal formulas of the MT and KT models. These findings provide a comprehensive understanding of the two models in calculating the effective modulus of rocks, which are beneficial to such areas as petroleum exploration and exploitation, civil engineering, and geophysics.

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Peng, Jun, Louis Ngai Yuen Wong, and Cee Ing Teh. "Influence of grain size on strength of polymineralic crystalline rock: New insights from DEM grain-based modeling." Journal of Rock Mechanics and Geotechnical Engineering 13, no. 4 (August 2021): 755–66. http://dx.doi.org/10.1016/j.jrmge.2021.01.011.

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Zvereva, Valentina, Anastasiya Lysenko, and Konstantin Frolov. "Modern Minerals Formation Genesis in Kavalerovsky Tin–Ore District Technogenic System (Primorsky Krai)." Minerals 10, no. 2 (January 21, 2020): 91. http://dx.doi.org/10.3390/min10020091.

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Parameters and conditions of crystallization for the majority of hypergenic and technogenic minerals have not yet been studied, as their determination is often difficult due to their imperfect crystalline structure (X-ray amorphous) and formation in polymineral compounds. The article discusses the formation conditions of 20 hypergenic and technogenic minerals from technogenic waters in the mining industrial system of the Kavalerovsky district tin–sulfide deposits (Primorsky krai) in Russia. For various ratios of hypogenic minerals–host rocks in ore and in tailings in a wide temperature range (from −25 to 45 °C), the Eh-pH parameters and the minerals paragenesis were established. All hypergenic and technogenic minerals formed during modeling were found and diagnosed in the Kavalerovsky tin–ore district mining industrial technogenic system.

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Dyakiv, Vasyl, and Zenon Hevpa. "Opinion of the karstological situation and state of the mining massif of rudnik № 2 of the Stebnitsky ghp polymineral by results of experimental and material-balance modeling." Visnyk of the Lviv University. Geology Series 35, no. 35 (2021): 91–110. http://dx.doi.org/10.30970/vgl.35.08.

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An analysis of the dynamics of flooding of rudnik N 2 Stebnitsky GHP “Polymineral”, restoration of groundwater levels, observed variability of chemical composition in mine workings, formation of natural hydrogeological stratification of the underground hydrosphere, development of karstological situation and assessment of its actual state. It is proved that after the failure that took place on March 15, 2020, there was an accelerated flooding of mine workings, underground karst cavities and saline deposits by September 2020, with gradual extinction and cessation of technogen-activity karst as flooding of supersalt deposits by August 2021 and formation equilibrium with salt rocks chemical composition of brines. The termination of the karst process is also proved on the basis of the results of experimental and material-balance modeling.

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Joy, K. H., J. F. Snape, A. A. Nemchin, R. Tartèse, D. M. Martin, M. J. Whitehouse, V. Vishnyakov, J. F. Pernet-Fisher, and D. A. Kring. "Timing of geological events in the lunar highlands recorded in shocked zircon-bearing clasts from Apollo 16." Royal Society Open Science 7, no. 6 (June 2020): 200236. http://dx.doi.org/10.1098/rsos.200236.

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Apollo 16 soil-like regolith breccia 65745,7 contains two zircon-bearing clasts. One of these clasts is a thermally annealed silica-rich rock, which mineralogically has affinities with the High Alkali Suite (Clast 1), and yields zircon dates ranging from 4.08 to 3.38 Ga. The other clast is a KREEP-rich impact melt breccia (Clast 2) and yields zircon dates ranging from 3.97 to 3.91 Ga. The crystalline cores of both grains, which yield dates of ca 3.9 Ga, have undergone shock pressure modification at less than 20 GPa. We interpret that the U-Pb chronometer in these zircon grains has been partially reset by the Imbrium basin-forming event when the clasts were incorporated into the Cayley Plains ejecta blanket deposit. The zircon grains in Clast 1 have been partially decomposed, resulting in a breakdown polymineralic texture, with elevated U, Pb and Th abundances compared with those in the crystalline zircon. These decomposed areas exhibit younger dates around 3.4 Ga, suggesting a secondary high-pressure, high-temperature event, probably caused by an impact in the local Apollo 16 highlands area.

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Nagornov, Roman S., Pavel B. Razgovorov, Anastasiya M. Lepilova, Yuliya I. Stroganova, Pavel R. Smirnov, and Sergeiy P. Kochetkov. "GENTLE ACTIVATION OF POLYMINERAL SORBENT AND ITS INFLUENCE ON CLEANING PROCESS OF OIL-CONTAINING MEDIA FROM IMPURITY INGREDIENTS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no. 8 (August 29, 2017): 53. http://dx.doi.org/10.6060/tcct.2017608.5618.

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An attempt to evaluate the effect of gentle activation of the surface of polymineral sorbent – blue clay with oxalic acid (Kdis = 5.6∙10-2) and sodium carbonate was carried out. The chemical structure of the initial and activated materials was established by the X-ray phase analysis. The prospect of their use for the sorption extraction of impurity ingredients from oil-containing media was revealed. An important rock-forming mineral in a composition of polymineral sorbent is montmorillonite. It was found that 45 mass% of the powder material has a particle size of 0.3-2.5 μm (quartz, cristoballite), 21% of the particles have a size of 5-10 μm and a small part (≤ 9%) is more than 10 μm. As a result of gentle activation of the sorbent with a 6% solution of oxalic acid, a clearer crystallized surface forms on which the effect of increasing the total pore size (100 nm - 2 μm) is observed. Such activated material is the meso- (20-500 Ǻ) type and macroporous type (> 500 Ǻ). The atomic composition of the renewed surface indicates the partial destruction of kaolinite during acid activation with an additional effect on impurity hydromica and a balancing increase in the mass fraction of quartz and saponite fractions (scaly particle form, 1-3 μm). The data of IR spectroscopic studies confirm the consistency of the judgments. Sequential activation with a solution of alkaline earth metals and sodium carbonate ensures the formation of tortuous pores and the production of disparate and relatively shallow (no more than 5 μm) particles in comparison with the original (globules up to 50 μm are encountered). The observed texture is a loosened land material of a complex chemical composition with the inclusion of natural grains of quartz, crystals (montmorillonite), fibrous structures and individual flakes. When 1% by weight of a polymineral sorbent based on montmorillonite and SiO2 was introduced into linseed oil, it was found that its treatment with 6% solutions of oxalic and succinic acid promotes an increase in the degree of purification from fatty acids to 40% and from peroxide compounds to 40%, then as gentle acid-alkaline activation of the sorbent provides the production of an oil-containing product with an even lower (by 5%) concentration of fatty acids.Forcitation:Nagornov R.S., Razgovorov P.B., Lepilova A.M., Stroganova Yu.I., Smirnov P.R., Kochetkov S.P. Gentle activation of polymineral sorbent and its influence on cleaning process of oil-containing media from impurity ingredients. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 53-59.

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Ohe, T., B. Zou, K. Noshita, I. Gomez-Morilla, C. Jeynes, P. M. Morris, and R. A. Wogelius. "Adsorption and diffusion of strontium in simulated rock fractures quantified via ion beam analysis." Mineralogical Magazine 76, no. 8 (December 2012): 3203–15. http://dx.doi.org/10.1180/minmag.2012.076.8.33.

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Abstract:

AbstractAn experimental technique has been developed and applied to the problem of determining effective diffusion coefficients and partition coefficients of Sr in low permeability geological materials. This technique, the micro-reactor simulated channel method (MRSC), allows rapid determination of contaminant transport parameters with resulting values comparable to those determined by more traditional methods and also creates product surfaces that are amenable for direct chemical analysis. An attempt to further constrain mass flux was completed by detailed ion beam analysis of polished tuff surfaces (tuff is a polycrystalline polyminerallic aggregate dominated by silicate phases) that had been reacted with Sr solutions at concentrations of 10−5, 10−3 and 10−1 mol l−1. Ion beam analysis was carried out using beams of both protons (using particle induced X-ray emission and elastic backscattering spectrometry or EBS) and alpha-particles (using Rutherford backscattering spectrometry). The ion beam analyses showed that increased solution concentrations resulted in increased surface concentrations and that in the highest concentration experiment, Sr penetrated to at least 4 μm below the primary interface. The Sr surface concentrations determined by EBS were 0.06 (±0.05), 0.87 (±0.30) and 2.40 (±1.0) atomic weight % in the experiments with starting solution concentrations of 10−5, 10−3, and 10−1 mol l−1, respectively.

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Fomina, Ekaterina V., Natalia I. Kozhukhova, Evgeny A. Belovodsky, V. A. Klimenko, and Marina I. Kozhukhova. "Microstructural Analysis of Changes in the Morphology of Quartz Raw Materials of Different Genesis at Dry Milling." Materials Science Forum 1017 (January 2021): 91–100. http://dx.doi.org/10.4028/www.scientific.net/msf.1017.91.

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The influence of the genesis of quartz-containing rocks on the strength of particles and changes in morphology during destruction from the standpoint of the mineralogical approach in the development of the scientific direction "geonics" ("geomimetics") has been investigated. The kinetics of dry grinding of raw materials in a laboratory ball roller mill was carried out. The features of the formation and development of cracks, particle size distribution, changes in the morphology and microstructure of fragments have been studied. It was found that in natural quartz cracks develop along the surface, where the highest concentration of impurities creates a defect structure with destruction into small particles. The purest structure of hydrothermal quartz is susceptible to brittle fracture into fragments similar in morphology to the base particle. Reducing the defectiveness of the structure increases the strength of the crystals. The internal energy potential of techno genic raw materials is determined by its defective structure, which undergoes the greatest deformations during grinding, allowing obtaining the maximum values of the specific surface area and reduce the grinding time. A difference in the degree of crystallinity of quartz, which composes the polymineral techno genic raw materials, makes it possible to obtain the optimal granulometry of fine particles. The conducted research is aimed at identifying the mechanisms of destruction of quartz rocks and can be used in solving engineering problems not only in construction materials science, but also in geotechnics.

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Fomina, Ekaterina V., Natalia I. Kozhukhova, Evgeny A. Belovodsky, V. A. Klimenko, and Marina I. Kozhukhova. "Microstructural Analysis of Changes in the Morphology of Quartz Raw Materials of Different Genesis at Dry Milling." Materials Science Forum 1017 (January 2021): 91–100. http://dx.doi.org/10.4028/www.scientific.net/msf.1017.91.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

The influence of the genesis of quartz-containing rocks on the strength of particles and changes in morphology during destruction from the standpoint of the mineralogical approach in the development of the scientific direction "geonics" ("geomimetics") has been investigated. The kinetics of dry grinding of raw materials in a laboratory ball roller mill was carried out. The features of the formation and development of cracks, particle size distribution, changes in the morphology and microstructure of fragments have been studied. It was found that in natural quartz cracks develop along the surface, where the highest concentration of impurities creates a defect structure with destruction into small particles. The purest structure of hydrothermal quartz is susceptible to brittle fracture into fragments similar in morphology to the base particle. Reducing the defectiveness of the structure increases the strength of the crystals. The internal energy potential of techno genic raw materials is determined by its defective structure, which undergoes the greatest deformations during grinding, allowing obtaining the maximum values of the specific surface area and reduce the grinding time. A difference in the degree of crystallinity of quartz, which composes the polymineral techno genic raw materials, makes it possible to obtain the optimal granulometry of fine particles. The conducted research is aimed at identifying the mechanisms of destruction of quartz rocks and can be used in solving engineering problems not only in construction materials science, but also in geotechnics.

Journal articles on the topic 'Polymineralic rocks'

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