Journal articles on the topic 'Accessory mineral'
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1
Jefferies, N. L. "The distribution of the rare earth elements within the Carnmenellis pluton, Cornwall." Mineralogical Magazine 49, no. 353 (September 1985): 495–504. http://dx.doi.org/10.1180/minmag.1985.049.353.02.
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AbstractThe Carnmenellis pluton is a post-orogenic granite of Hercynian age, comprised largely of porphyritic biotite granites which possess LREE enriched patterns with slight negative Eu anomalies. Electron microprobe and ICP spectrometry data are presented for monazite, which occurs as an accessory mineral in all granite types, and it is demonstrated that this mineral is the principal host for LREE in the biotite granites. HREE are strongly partitioned into the accessory minerals xenotime, apatite, and zircon; only Eu substitutes significantly into the essential minerals. The behaviour of the REE during granite differentiation is controlled by the behaviour of the radioactive accessory minerals, which limits the usefulness of these elements in the petrogenetic modelling of granitic rocks.
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Clarke, D. Barrie, Axel D. Renno, David C. Hamilton, Sabine Gilbricht, and Kai Bachmann. "The spatial association of accessory minerals with biotite in granitic rocks from the South Mountain Batholith, Nova Scotia, Canada." Geosphere 18, no. 1 (December 22, 2021): 1–18. http://dx.doi.org/10.1130/ges02339.1.
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Abstract We use mineral liberation analysis (MLA) to quantify the spatial association of 15,118 grains of accessory apatite, monazite, xenotime, and zircon with essential biotite, and clustered with themselves, in a peraluminous biotite granodiorite from the South Mountain Batholith in Nova Scotia (Canada). A random distribution of accessory minerals demands that the proportion of accessory minerals in contact with biotite is identical to the proportion of biotite in the rock, and the binary touching factor (percentage of accessory mineral touching biotite divided by modal proportion of biotite) would be ~1.00. Instead, the mean binary touching factors for the four accessory minerals in relation to biotite are: apatite (5.06 for 11,168 grains), monazite (4.68 for 857 grains), xenotime (4.36 for 217 grains), and zircon (5.05 for 2876 grains). Shared perimeter factors give similar values. Accessory mineral grains that straddle biotite grain boundaries are larger than completely locked, or completely liberated, accessory grains. Only apatite-monazite clusters are significantly more abundant than expected for random distribution. The high, and statistically significant, binary touching factors and shared perimeter factors suggest a strong physical or chemical control on their spatial association. We evaluate random collisions in magma (synneusis), heterogeneous nucleation processes, induced nucleation in passively enriched boundary layers, and induced nucleation in actively enriched boundary layers to explain the significant touching factors. All processes operate during the crystallization history of the magma, but induced nucleation in passively and actively enriched boundary layers are most likely to explain the strong spatial association of phosphate accessories and zircon with biotite. In addition, at least some of the apatite and zircon may also enter the granitic magma as inclusions in grains of Ostwald-ripened xenocrystic biotite.
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Reid, Christopher, Rebecca Lunn, Gráinne El Mountassir, and Alessandro Tarantino. "A mechanism for bentonite buffer erosion in a fracture with a naturally varying aperture." Mineralogical Magazine 79, no. 6 (November 2015): 1485–94. http://dx.doi.org/10.1180/minmag.2015.079.6.23.
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AbstractIn the deep geological disposal of nuclear waste in crystalline rock, erosion of the bentonite buffer may occur during periods of glaciation. Previous researchers have examined the mechanism and rates of extrusion and erosion for purified montmorillonite samples in smooth planar fractures. In this paper, we investigate the influence of using MX-80 material (as delivered, i.e. including accessory minerals) and a naturally varying aperture on bentonite erosion. A bespoke fracture flow cell was constructed for this purpose and flow through conducted with deionized water. Throughout the experiment, gravimetric analysis was undertaken on the effluent and the swelling pressure of the bentonite monitored. Quantitative image analysis of the extrusion process was also undertaken. When the swelling pressure data were analysed, alongside both the oscillations in erosion rate and the area of the accessory-mineral ring, a two-stage mechanism governing the erosion process became apparent. Once an accessory-mineral ring had formed at the edge of the extruded material, further increases in swelling pressure resulted in a breach in the accessory-mineral ring, triggering an erosive period during which, the mineral ring was supplemented with additional minerals. The cycle repeated until the ring was sufficiently strong that it remained intact. This observed process results in erosion rates one order of magnitude less than those currently used in long-term safetycase calculations.
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Georgieva, Sylvina, Rossitsa Vassileva, and Georgi Milenkov. "Mineral association in pegmatites from the Djurkovo Pb-Zn deposit, Central Rhodopes: preliminary results." Review of the Bulgarian Geological Society 83, no. 3 (December 2022): 19–22. http://dx.doi.org/10.52215/rev.bgs.2022.83.3.19.
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Deformed pegmatites of varying thickness and position are a significant constituent intruded in the metamorphic complex, hosting the Djurkovo Pb-Zn deposit in Central Rhodopes. The mineral composition of the pegmatites consists of plagioclase, K-feldspar, quartz, and minor micas. The main accessory minerals are allanite, titanite, apatite and zircon. Late hydrothermal alteration of pegmatites led to the formation of epidote, adularia, sericite, chlorite, carbonate, quartz and leucoxene. Rare earth carbonate-phosphate assemblage (REE+Y, Th, U), manifested as ˂ 20 µm anhedral grains, is observed along fractures and dissolved zones in allanite and titanite. Because of the limited mobility of REE in fluids, these elements are barely transported during the hydrothermal activity and are incorporated in new phases, precipitated in the frames of the altered accessory minerals. The studied pegmatites contain a significant amount of accessory minerals rich in incompatible elements and therefore could be considered as their potential source.
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Köster, H. M. "Mineralogical and chemical heterogeneity of three standard clay mineral samples." Clay Minerals 31, no. 3 (September 1996): 417–22. http://dx.doi.org/10.1180/claymin.1996.031.3.11.
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AbstractMineralogical and chemical heterogeneity within three standard clay mineral samples have been identified by X-ray diffraction and chemical analysis of various size-fractions. This heterogeneity is partly attributed to accessory minerals, but mostly to structural and compositional variations in the 2:1 layer minerals of different particle size in the same specimen.
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Belkin, Harvey E., and Ray Macdonald. "Zirconium-bearing accessory minerals in UK Paleogene granites: textural, compositional, and paragenetic relationships." European Journal of Mineralogy 33, no. 5 (September 23, 2021): 537–70. http://dx.doi.org/10.5194/ejm-33-537-2021.
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Abstract. The mineral occurrences, parageneses, textures, and compositions of Zr-bearing accessory minerals in a suite of UK Paleogene granites from Scotland and Northern Ireland are described. Baddeleyite, zirconolite, and zircon, in that sequence, formed in hornblende + biotite granites (type 1) and hedenbergite–fayalite granites (type 2). The peralkaline microgranite (type 3) of Ailsa Craig contains zircon, dalyite, a eudialyte-group mineral, a fibrous phase which is possibly lemoynite, and Zr-bearing aegirine. Hydrothermal zircon is also present in all three granite types and documents the transition from a silicate-melt environment to an incompatible element-rich aqueous-dominated fluid. No textures indicative of inherited zircon were observed. The minerals crystallized in stages from magmatic through late-magmatic to hydrothermal. The zirconolite and eudialyte-group mineral are notably Y+REE-rich (REE signifies rare earth element). The crystallization sequence of the minerals may have been related to the activities of Si and Ca, to melt peralkalinity, and to local disequilibrium.
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Oziegbe, E. J., O. O. Ocan, and A. O. Buraimoh. "Petrography of Allanite-bearing Tonalite from Iwo Region, Osun State, Nigeria." Materials and Geoenvironment 67, no. 2 (July 27, 2020): 79–89. http://dx.doi.org/10.2478/rmzmag-2020-0006.
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AbstractPrimary, secondary and accessory minerals in tonalitic rocks from Iwo region of the Precambrian Basement Complex of Southwestern Nigeria were identified and analysed with the aim of determining the various processes involved during the crystallisation of magma. Thin sections of tonalite were prepared and studied with the aid of a petrographic microscope. The mineral assemblages observed are biotite, plagioclase, alkali-feldspar, amphiboles, pyroxene, quartz, muscovite and chlorite. Allanite, titanite, apatite and zircon occur as accessory minerals. Muscovite and chlorite are found to be secondary minerals. The mineral allanite has a characteristic form of zoning and shows evidence of metamictisation, and is surrounded by dark-coloured biotite having radioactive haloes. Titanite is anhedral to subhedral crystals and forms reaction rim round opaque minerals. Plagioclase shows evidence of compositional zoning as well as plastic deformation of the twin lamellae. The allanite observed is primary in nature and has undergone radioactive disintegration; chlorite and muscovite are formed by secondary processes of chloritization and sericitisation, respectively. The tonalite is formed as a result of rapid cooling of magma close to the Earth's surface.
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Tóth, Erzsébet, Tamás G. Weiszburg, Teresa Jeffries, C. Terry Williams, András Bartha, Éva Bertalan, and Ildikó Cora. "Submicroscopic accessory minerals overprinting clay mineral REE patterns (celadonite–glauconite group examples)." Chemical Geology 269, no. 3-4 (January 2010): 312–28. http://dx.doi.org/10.1016/j.chemgeo.2009.10.006.
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Yurichev, Alexey. "Gold and silver accessory minerals in ultramafites of the Kyzyr-Burlyuksky ultramafic massif (Western Sayan)." Ores and metals, no. 4 (January 10, 2022): 109–20. http://dx.doi.org/10.47765/0869-5997-2021-10031.
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The study focuses on gold and silver accessory minerals
(native silver, cuprous gold, luanheite (Ag3Hg),
unspecified mineral phase (Cu,Ag,Hg), first diagnosed
in dunites and apodunite serpentinites of the Kyzyr-Burlyuksky
ultramafic massif, which is part of the Kurtushibin
ophiolite belt of Western Sayan. The revealed
ore minerals are mainly observed in the form of single
hypidiomorphic, irregular microscopic precipitates (0.5–
3.0 μm) mainly inside magnetite, much less often in
grains of avaruite. Typomorphic and chemical features
of ore minerals, their natural setting in rock-forming
silicate matrix are characterized. Formation and concentration
of these accessory minerals is associated with
superimposed low-temperature transformation (hydration)
processes affecting original ultramafic rocks. At the
same time, the presence of luanheite and an unnamed
phase (Cu,Ag,Hg), along with the previously identified
potarite (PdHg), is probably evidence of low-temperature
conditions of mineral formation during the manifestation
of epigenetic processes of serpentinization (lowgrade
metamorphism) due to solutions enriched in mercury.
The source of such solutions could be gabbro intrusions
that penetrated later into the main ultramafic body.
10
Dahlquist, J. A. "REE fractionation by accessory minerals in epidote-bearing metaluminous granitoids from the Sierras Pampeanas, Argentina." Mineralogical Magazine 65, no. 4 (August 2001): 463–75. http://dx.doi.org/10.1180/002646101750377506.
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AbstractA study of the distribution of REE in epidote-bearing metaluminous granitoids from Sierra de Chepes, Sierras Pampeanas, Argentina, reveals that a large proportion of the REE reside in the accessory minerals (allanite, epidote, titanite, apatite and zircon), and therefore these minerals control the behaviour of REE in granitic magmas. Well-developed chemical zonation in titanite indicates that the REE content decreases in the melt during crystallization of this mineral. The textural and chemical characteristics of euhedral epidote suggest a magmatic origin, and in that case it may have played an important role in the fractionation of the REE. The amount of silica and any other geochemical parameter indicative of fractionation progress in the dominant granodioritic-tonalitic facies (gtf) do not correlate with observed variations in the REE patterns. When many accessory minerals are involved, as in the gtf, the differentiated melts (e.g. aplites) are REE poor. Thus, the presence/absence of accessory minerals in granitoids can be indicative of the generation of differentiated melt enriched or poor in REE and other trace elements. This may have an economic significance, as it may allow us to predict the probable geochemistry of the differentiated melts (i.e. those that tend to develop mineralization) from the textural analysis of the ‘regional’ granitic rock.Finally, the type and abundance of accessory minerals in the granitic suite can also help us to define the geotectonic environment where magmas were generated.
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Guggenheim, s., and R. T. Martin. "Definition of clay and clay mineral: joint report of the AIPEA and CMS Nomenclature Committees." Clay Minerals 30, no. 3 (September 1995): 257–59. http://dx.doi.org/10.1180/claymin.1995.030.3.09.
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AbstractThe definition of ‘clay’ was first formalized in 1546 by Agricola. It has been revised many times since, although the fundamentals involving plasticity, particle size, and hardening on firing were retained by most. For an exhaustive account of the history of the definition to 1963, the reader is referred to Mackenzie (1963). More recent developments may be found in Weaver (1989).The definition of clay raises the important issue of clay constituents and, implicitly, the definition of ‘clay mineral'. Mackenzie (1963, p. 15) noted the inappropriateness of defining clay mineral as “any mineral which occurs in clay” since, among several reasons, it would include many accessory minerals that are not characteristic of clay.
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Šćavničar, Stjepan, Vladimir Bermanec, Goran Kniewald, Delko Barišić, and Višnja Oreščanin. "Uranium Minerals in the Radlovac Series Metasediments at Mt. Papuk, Croatia." Geologia Croatica 60, no. 2 (2007): 165–71. http://dx.doi.org/10.4154/gc.2007.05.
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Applying a combination of different methods – X-ray diffraction, scanning electron microscopy, gamma-spectroscopy and X-ray spectroscopy, a suite of uranium minerals, meta-torbernite, meta-uranospinite and meta-zeunerite was identified in metasediments of the Radlovac series at the Mt. Papuk area, Croatia. The accessory minerals galenaa, zircon, rutile, chalcopyrite and cuprite, as well as an unidentified Ni-bearing phase are also present. The mineral assemblage indicates a sequence of epigenetic and supergene processes affecting the Radlovac series.
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Poitrasson, Franck, John M. Hanchar, and Urs Schaltegger. "The current state and future of accessory mineral research." Chemical Geology 191, no. 1-3 (November 2002): 3–24. http://dx.doi.org/10.1016/s0009-2541(02)00146-8.
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Sukharev, A. E., V. I. Silaev, and A. F. Khazov. "The Phenomenon of Petrovskiy (to the 75th Anniversary)." Вестник Пермского университета. Геология 20, no. 1 (2021): 75–91. http://dx.doi.org/10.17072/psu.geol.20.1.75.
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Brief scientific biography of a well-known scientist, a leader in the field of experimental study of crystallization processes with usage the holographic method for quantitative analysis of temperature-convective inhomogeneities in the «growth-criticalstone» system, a specialist in crystallographic-mineralogical study of diamonds and their accessory minerals, a successful researcher of modern mineral formation at Kamchatka volcanoes, one of the founders of the «literally from scratch» enterprise for the production of industrial diamonds.
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Chung, Baru, Jaehyung Yu, Lei Wang, Nam Hoon Kim, Bum Han Lee, Sangmo Koh, and Sangin Lee. "Detection of Magnesite and Associated Gangue Minerals using Hyperspectral Remote Sensing—A Laboratory Approach." Remote Sensing 12, no. 8 (April 22, 2020): 1325. http://dx.doi.org/10.3390/rs12081325.
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This study introduced a detection method for magnesite and associated gangue minerals, including dolomite, calcite, and talc, based on mineralogical, chemical, and hyperspectral analyses using hand samples from thirteen different source locations and Specim hyperspectral short wave infrared (SWIR) hyperspectral images. Band ratio methods and logistic regression models were developed based on the spectral bands selected by the random forest algorithm. The mineralogical analysis revealed the heterogeneity of mineral composition for naturally occurring samples, showing various carbonate and silicate minerals as accessory minerals. The Mg and Ca composition of magnesite and dolomite varied significantly, inferring the mixture of minerals. The spectral characteristics of magnesite and associated gangue minerals showed major absorption features of the target minerals mixed with the absorption features of accessory carbonate minerals and talc affected by mineral composition. The spectral characteristics of magnesite and dolomite showed a systematic shift of the Mg-OH absorption features toward a shorter wavelength with an increased Mg content. The spectral bands identified by the random forest algorithm for detecting magnesite and gangue minerals were mainly associated with spectral features manifested by Mg-OH, CO3, and OH. A two-step band ratio classification method achieved an overall accuracy of 92% and 55.2%. The classification models developed by logistic regression models showed a significantly higher accuracy of 98~99.9% for training samples and 82–99.8% for validation samples. Because the samples were collected from heterogeneous sites all over the world, we believe that the results and the approach to band selection and logistic regression developed in this study can be generalized to other case studies of magnesite exploration.
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Sturm, Robert. "Analysis of Magmatic Crystal Destruction by Backscattered Electron Imaging." Microscopy Today 30, no. 5 (September 2022): 21–23. http://dx.doi.org/10.1017/s1551929522001092.
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Abstract:After their crystallization from magmatic melt, minerals such as accessory zircon are often subject to different kinds of chemical impairment. This includes the radiation-induced damage of the crystal lattice due to the incorporation of radioactive elements (U, Th) and the dissolution of the mineral structure due to the permanent action of aggressive fluid phases. Both phenomena can be best studied by using specific crystal sections and electron microscopy visualization techniques (backscattered electron imaging, BSEI). Crystal damage by the emission of α-particles corresponds to a continuous transformation of the regularly structured lattice into an amorphous mass. Mineral dissolution is expressed by the formation of specific corrosion pits, which may be refilled by recrystallized material.
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Vukov, Milenko, and Dragan Milovanovic. "The Polumir granite: Addititional data on its origin." Annales g?ologiques de la Peninsule balkanique, no. 64 (2002): 167–85. http://dx.doi.org/10.2298/gabp0264167v.
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The Polumir granite is exposed on several localities due to erosion, and its chemical and mineral composition is presented in this paper. It is built of K-feldspar, plagioclase, myrmekite, metasomatic albite, biotite, muscovite and quartz, while apatite, magnetite, monazite, allanite and zircon are present as accessory minerals. According to its chemical and mineral composition and rock chemistry (trace and REE elements) the Polumir granite is leucocratic, sin-collisional, with S-type characteristics. It crystallized at temperature of about 650?C and under pressure of 2-4 kbar. Results of isotope analyses (K-Ar method on biotites) indicate that the Polumir granite was formed during the Miocene (14-19 Ma) and it has undergone subsequent weak remobilization afterwards.
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Bulakh, Andrei, Georgii Popov, Svetlana Yanson, and Mikhail Ivanov. "New data on the granite pedestal of the monument to Peter the Great “The Bronze Horseman” in Saint Petersburg." Journal of Mining Institute 248 (May 25, 2021): 180–89. http://dx.doi.org/10.31897/pmi.2021.2.2.
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In order to expand and popularize knowledge about the stone decoration of Saint Petersburg, we present new data on the mineralogy and petrography of the famous Thunder-Stone, the parts of which were the basis for the monument to Peter the Great – the legendary “Bronze Horseman”. In the course of studying geological documentation of the monument's granite base, we examined the mineral composition and internal structure of granite, as well as the fragments of a pegmatite vein and veinlets found in it. 25 single-mineral samples were collected from the available micro-scaled shear fractures within the pedestal surface and studied by electron microscopy, electron probe and X-ray phase analysis. It was established that K-Na feldspar in the granite composition was represented by microcline, whereas micas were represented by annite-siderophyllite and muscovite. Accessory minerals included monazite, xenotime, thorite, zircon, rutile, apatite, fluorite, Ti-, Nb-, Ta-bearing minerals, uranium phosphates. The presence of topaz is characteristic of pegmatites. The revealed structural and textural features of four granite boulders in the monument pedestal, as well as mineralogical and chemical composition of their rock-forming and accessory minerals, showed the similarity of this rock to Precambrian biotite-muscovite granites and topaz-containing pegmatites (stockscheiders) of the late formation phase of the Vyborg rapakivi granite massif. The research results are considered as the basis for further geological and mineralogical study of the Thunder-Stone origin and determining the place of its separation from the primary source.
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Bagiński, Bogusław, and Ray Macdonald. "The chevkinite group: underestimated accessory phases from a wide range of parageneses." Mineralogia 44, no. 3-4 (July 1, 2013): 99–114. http://dx.doi.org/10.2478/mipo-2013-0006.
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AbstractChevkinite-group minerals are widespread in a very wide range of igneous and metamorphic parageneses, forming important components of accessory mineral assemblages. Their presence in a rock may be difficult to establish by standard optical techniques, which has contributed to their importance being underestimated; a combination of SEM and EMPA is recommended here. Currently, there are eleven IMAapproved members of the group but undoubtedly several more will be described in the near future. There is considerable compositional variation in the group, which can be expressed as: REE + M2+C + M3+C = Ca2+ A + Sr + Ti4+C + Zr4+C where A and C are structural sites. Chevkinite-group minerals strongly fractionate geochemically coherent pairs, such as LREE-HREE, Nb-Ta, Zr-Hf and Th-U, and thus play a critical role in geochemical modelling.
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Glukhov, Yu V., B. A. Makeev, and M. Yu Sokerin. "Typomorphism of hypogene accessory mineralsof the Vymsky Horst structure (Middle Timan). Olivine, pyropes." Vestnik of Geosciences 10 (2020): 3–11. http://dx.doi.org/10.19110/geov.2020.10.1.
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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.
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von Quadt, Albrecht, Jörn-Frederik Wotzlaw, Yannick Buret, Simon J. E. Large, Irena Peytcheva, and Anne Trinquier. "High-precision zircon U/Pb geochronology by ID-TIMS using new 1013 ohm resistors." Journal of Analytical Atomic Spectrometry 31, no. 3 (2016): 658–65. http://dx.doi.org/10.1039/c5ja00457h.
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Mikhailova, Julia A., Yakov A. Pakhomovsky, Natalia G. Konopleva, Andrey O. Kalashnikov, and Victor N. Yakovenchuk. "Fluorine Controls Mineral Assemblages of Alkaline Metasomatites." Minerals 12, no. 9 (August 25, 2022): 1076. http://dx.doi.org/10.3390/min12091076.
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In the Khibiny and Lovozero alkaline massifs, there are numerous xenoliths of the so-called ‘aluminous hornfelses’ composed of uncommon mineral associations, which, firstly, are ultra-aluminous, and secondly, are highly reduced. (K,Na)-feldspar, albite, hercynite, fayalite, minerals of the phlogopite-annite and cordierite-sekaninaite series, corundum, quartz, muscovite, sillimanite, and andalusite are rock-forming minerals. Fluorite, fluorapatite, ilmenite, pyrrhotite, ulvöspinel, troilite, and native iron are characteristic accessory minerals. The protolith of these rocks is unknown. We studied in detail the petrography, mineralogy, and chemical composition of these rocks and believe that hornfelses were formed as a result of the metasomatic influence of foidolites. The main reason for the formation of an unusual aluminous association is the high mobility of aluminum promoted by the formation of fluid expelled from foidolites of the Na-Al-OH-F complexes. Thus, it is fluorine that controls the mobility of aluminum in the fluid and, consequently, the mineral associations of alkaline metasomatites. The gain of alkalis and aluminum to rocks of protolith was the reason for the intense crystallization of (K,Na)-feldspar. As a result, a SiO2 deficiency was formed, and Si-poor, Al-rich silicates and/or oxides crystallized.
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Yang, Yue-Heng, Fu-Yuan Wu, Yang Li, Jin-Hui Yang, Lie-Wen Xie, Yan Liu, Yan-Bin Zhang, and Chao Huang. "In situ U–Pb dating of bastnaesite by LA-ICP-MS." J. Anal. At. Spectrom. 29, no. 6 (2014): 1017–23. http://dx.doi.org/10.1039/c4ja00001c.
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Saveliev, Dmitry E., and Ivan A. Blinov. "Noble metal mineralization in apatite titanomagnetite ores of the Suroyam massif (Middle Urals)." Georesursy 22, no. 4 (December 2020): 98–100. http://dx.doi.org/10.18599/grs.2020.4.98-100.
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The mineralogical composition of apatite-titanomagnetite clinopyroxenites of the Suroyam massif, characterized by stable elevated contents of platinum group elements with the leading role of palladium, has been studied. In association with accessory chalcopyrite, palladium and silver minerals have been identified – mertieite, merenskyite, hessite. It has been suggested that the presence of intrinsic mineral phases of palladium, represented by tellurides and arsenides-antimonides, allows us to consider the Suroyam massif as a promising deposit of complex Pd-P-Fe ores.
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Paterson, B. A., W. E. Stephens, and D. A. Herd. "Zoning in granitoid accessory minerals as revealed by backscattered electron imagery." Mineralogical Magazine 53, no. 369 (March 1989): 55–61. http://dx.doi.org/10.1180/minmag.1989.053.369.05.
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AbstractAccessory minerals are often difficult to investigate with light optics as the mineral grains tend to be small and the refractive indices high. Textural features due to variations in composition are well displayed in such minerals by backscattered electron imagery under circumstances designed to select only the composition contribution to electron backscattering and displayed as atomic number (Z)-contrast imagery (ZCI). It is shown by this technique that compositional zonation patterns are very common and sector zoning in titanite is described for the first time. The compositional basis for zonation of titanites in this study is shown to be controlled by coupled substitutions involving the REE. The technique is particularly good at revealing rounded cores to zircon grains which are normally taken to be refractory grains from the magma source region, and ZCI studies may improve targeting of grains for U-Pb geochronological investigations. Several examples are presented of applications of the technique to accessory minerals encountered in polished thin sections of granitoids in the Caledonian of Scotland. The consequences of ZCI studies for trace element modelling of REE in granitoid petrogenesis are discussed.
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Sardi, Fernando, Adriana Heimann, and Pablo Grosse. "Non-pegmatitic beryl related to Carboniferous granitic magmatism, Velasco Range, Pampean Province, NW Argentina." Andean Geology 43, no. 1 (January 8, 2016): 86. http://dx.doi.org/10.5027/andgeov43n1-a05.
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The specialized leuco-monzogranite of the La Chinchilla Stock is a small Carboniferous stock located in the center of the Velasco Range, Pampean Province, La Rioja, Argentina. It is highly evolved and locally F- and Be-bearing, and has the potential for hosting U mineralization. Three different facies can be identified in the granitoid: border, porphyritic and equigranular facies. In all three facies the main minerals are quartz, microcline, plagioclase, biotite, and muscovite. Accessory minerals present in all facies include fluorite, zircon, and apatite. In addition, monazite, rutile, and uraninite occur as accessory minerals in the equigranular facies. Secondary minerals are muscovite, sericite, kaolinite, and opaque minerals. Secondary uranophane occurs in the equigranular and border facies. In localized areas, the equigranular facies contains small, green idiomorphic crystals of beryl (Be3Al2Si6O18) as accessory mineral. One of these beryl crystals was chemically analyzed for major and minor element contents using an electron microprobe and this information, along with fractional crystallization models and comparison with compositions of non-pegmatitic beryl from the literature, were used to understand the degree of evolution of the granitic melt. The chemical formula of beryl from the La Chinchilla Stock can be written as: C(Na0.014-0.033, K0.001-0.002, Ca0.001-0.004) T(2)(Be2.978-2.987, Li0.016-0.022) O(Al1.889-1.967, Fe0.045-0.103, Mg0.001-0.007, Mn0.001-0.007) T(1)(Si5.994-6.040O18). The alkali contents are low (Na2O<0.18 wt%; K2O<0.02 wt%), while FeOt is dominant among the divalent cations that substitute trivalent aluminum in the octahedral position of the mineral (FeOt/(MgO+MnO)>6; FeOt<1.27 wt%). In a longitudinal geochemical profile, Al enrichment is observed at the border while the highest Na content is found in an internal point. In a transversal geochemical profile, the highest concentration of Al is seen in an internal point while Na remains almost invariable. Ferromagnesian elements vary randomly within the crystal. This indicates compositional changes in the magma for Al, ferromagnesian elements, and Na. The FeOt content of the analyzed beryl is within the compositional range of other disseminated beryl from granitoids but slightly higher than that of beryl from hydrothermal veins and greisens. It contains similar to slightly lower amounts of FeOt, MgO, and Na2O than beryl from medium to little evolved granitic pegmatites. Overall, the composition of beryl in the La Chinchilla Stock is quite similar to that from medium to poorly evolved granitic pegmatites of the nearby Velasco Pegmatite District. The formation of beryl in the La Chinchilla Stock is attributed to precipitation from a F-bearing, highly fractionated, Al- and Si-rich melt saturated in BeO. A fractional crystallization model using Rb and Ba suggests that the beryl-hosting rock crystallized from the parent melt after extreme fractionation and 75% crystallization. The occurrence of beryl as a magmatic accessory mineral in the equigranular facies of the La Chinchilla Stock is indicative of a very high degree of fractionation of the parental magma.
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TANG, Ao, Guanglai LI, and Longquan ZHOU. "The Accessory Mineral Research in Maoping Pegmatite Type Tungsten Deposit." Acta Geologica Sinica - English Edition 88, s2 (December 2014): 38–39. http://dx.doi.org/10.1111/1755-6724.12367_19.
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Pereira, I. D. S., V. N. F. Lisboa, I. A. Silva, J. M. R. Figueirêdo, G. A. Neves, and R. R. Menezes. "Bentonite Clays from Sossego, Paraiba, Brazil: Physical and Mineralogical Characterization." Materials Science Forum 798-799 (June 2014): 50–54. http://dx.doi.org/10.4028/www.scientific.net/msf.798-799.50.
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In the northeastern region Brazil, especially in the State of Paraíba, there is a large incidence of non-metallic minerals, among which we may highlight the bentonite clay, ball clay, smectitic clay, kaolin... limestone and mica. In past years, there has been an intense research for discovering new deposits in the State of Paraíba, thus creating expectations for widening the mineral raw production in that region. So, this work is intended to make the physical, mineralogical and technological characterization of smectitic clays from the town of Sossego, PB, Brazil. The characterization was made by means of the following techniques: granulometric analysis by laser diffraction (GA), themogravimetric and differential thermal analysis (TG and DTA), chemical analysis (EDX) and X-ray diffraction (XRD). The results evidence that the studied clays present the following mineral phases: smectitic, kaolinite and accessory minerals such as quartz, carbonates feldspars and mica.
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Turbeville, B. N. "Sidewall differentiation in an alkalic magma chamber: evidence from syenite xenoliths in tuffs of the Latera caldera, Italy." Geological Magazine 130, no. 4 (July 1993): 453–70. http://dx.doi.org/10.1017/s0016756800020537.
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AbstractFeldspathoidal and quartz-bearing syenite xenoliths in c. 235 to 155 ka tuffs surrounding the Latera caldera have textures and mineral assemblages that indicate an origin from the crystalline margins of a shallow magma chamber. This lithic suite exhibits a diversity of plutonic fabrics; unaltered, glass-bearing nodules with undeformed sanidine frameworks coexist with completely crystallized clasts, many of which show evidence of subsolidus modification. The syenites comprise eutectic mineral assemblages with high percentages of titanite, apatite, and melanite garnet as accessory minerals. Ubiquitous reaction textures in syenite accompany progressive changes in mineral assemblages, and they show the decreasing influence of limestone contamination with distance from the contact of syenite and skarn wallrock. Diagnostic mineral assemblages include nepheline rich in calcite inclusions, coexisting titanite and metamorphic perovskite, zircon with baddeleyite inclusions, fluorapatite mantled by a possible carbonate-bearing apatite (francolite), melanite garnet intergrown with clinopyroxene, and interstitial haüyne rich in pyrrhotite inclusions.At Latera, pumice fragments in the same deposit can exhibit up to ten-fold differences in vesicularity and crystal content (from < 5 to > 50 vol. % phenocrysts). These clasts, in conjunction with glass-bearing syenite and skarn xenoliths, may represent a range of progressively crystallized magmas that were quenched at the instant of their eruptive entrainment. The major element abundances of pumices and syenite reflect the fractionation of plagioclase and sanidine, with lesser amounts of fassaitic diopside, leucite, biotite, apatite, and alkali amphibole. Trace element ratios (e.g. Rb/Sr, Nb/Ta, Zr/Hf, LREE/HREE), on the other hand, are highly variable for crystalline and pumiceous ejecta, and some element variations (e.g. Li, Ta, Nb, Th) cannot be entirely reconciled with simple crystal-liquid fractionation. The syenite clasts span a range of compositions from strongly fractionated assemblages rich in accessory minerals to compositions that more closely approximate quenched reservoir liquids. These features reflect processes that range from pure fractional crystallization to in situ crystallization where fractionated liquid was trapped in the pores of sidewall cumulates along the chamber roof and walls.
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Birk, Dieter. "Quantitative coal mineralogy of the Sydney Coalfield, Nova Scotia, Canada, by scanning electron microscopy, computerized image analysis, and energy-dispersive X-ray spectrometry." Canadian Journal of Earth Sciences 27, no. 2 (February 1, 1990): 163–79. http://dx.doi.org/10.1139/e90-017.
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Automated image and X-ray analysis, with a scanning electron microscope, has been used to "fingerprint" mineral particles in bituminous coals of the Sydney Coalfield and catalogue their chemical class and size distribution. Four seams (Hub, Harbour, Phalen, and Gardiner) were analyzed quantitatively for some 32 000 mineral particles; these analyses revealed particle-size and weight distributions for 27 chemical classes. Manual searches augmented the computer-automated scans, covering eight seams and recording a total of 35 mineral species, their paragenesis, and sites for 28 elements.Sydney seam mineralogy is dominated by pyrite and kaolinite, but illite, chlorite, siderite, ankerite, and quartz are locally prominent; these are accompanied by a large variety of accessory minerals (zircon, rutile, apatite, barite, gypsum, rare-earth phosphates, and ore minerals) and alteration products (goethite and hydrated sulphates). Individual column benches show geochemical fades with different mineral suites resulting from cyclic sedimentation, hydrologie conditions, and changes in pore-water chemistry during peat accumulation, coalification, and diagenesis. A sulphide facies and a siderite–chlorite facies are recognized within one seam (Harbour); these facies change vertically and laterally within lithotype bands.Stratigraphic correlation is precluded, but quantitative mineralogy can elucidate paleoenvironments and be applied to coal-cleaning technology (beneficiation) or environmental studies.
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Hurai, V., M. Huraiová, P. Konečný, and R. Thomas. "Mineral-melt-fluid composition of carbonate-bearing cumulate xenoliths in Tertiary alkali basalts of southern Slovakia." Mineralogical Magazine 71, no. 1 (February 2007): 63–79. http://dx.doi.org/10.1180/minmag.2007.071.1.63.
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AbstractTwo types of carbonatic cumulate xenoliths occur in alkali basalts of the northern part of the Carpatho-Pannonian region, Central Europe. One is dominated by Ca-Fe-Mg carbonates with randomly distributed bisulphide globules (Fe1+xS2, x = 0–0.1), Mg-Al spinel, augite, rhönite, Ni-Co-rich chalcopyrite, and a Fe(Ni,Fe)2S4 phase. The second, carbonatic pyroxenite xenolith type, is composed of diopside, subordinate fluorapatite, interstitial Fe-Mg carbonates, and accessory K-pargasite, F-Al-rich ferroan phlogopite, Mg-Al spinel, albite and K-feldspar. All accessory minerals occur in ultrapotassic dacite-trachydacite glass in primary silicate melt inclusions in diopside, together with calcio-carbonatite and CO2-N2-CO inclusions. Textural evidence is provided for multiphase fluid-melt immiscibility in both xenolith types. The carbonatic pyroxenite type is inferred to have accumulated from differentiated, volatile-rich, ultrapotassic magma derived by a very low-degree partial melting of strongly metasomatized mantle. Mineral indicators point to a genetic link between the carbonatite xenolith with olivine-fractionated, silica-undersaturated alkalic basalt ponded at the mantle-crust boundary.
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Oziegbe, E. J., V. O. Olarewaju, and O. O. Ocan. "MINERAL CHEMISTRY AND GEOCHEMISTRY OF HYPERSTHENE-BEARING DIORITE FROM ERUSU AKOKO, SOUTHWESTERN NIGERIA." Malaysian Journal of Geosciences 4, no. 1 (February 7, 2020): 13–18. http://dx.doi.org/10.26480/mjg.01.2020.13.18.
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Samples of mafic intrusive rock were analyzed for their mineralogical and chemical properties. The textural relationship was studied using the petrographic microscope, elemental composition of minerals was determined using the Electron Microprobe and the whole rock chemical analysis was done using the XRF and ICP-MS. The following minerals were observed in order of abundance; pyroxene, amphibole, plagioclase, biotite, opaque minerals, quartz and chlorite, with apatite and zircon occurring as accessory mineral. Two types of pyroxenes were observed; orthopyroxene (hypersthene) and clinopyroxene. Texturally, amphiboles have inclusions of plagioclase and pyroxene. The plagioclase has undergone sericitization. The chemical composition of the pyroxene is En51.95Fs44.53Wo3.52, biotite has Fe/(Fe+Mg):0.42, Mg/(Fe+Mg):0.59, and plagioclase is Ab63.5An34.55Or1.95. Whole rock chemistry shows a chemical composition; SiO2: 45.15 %, Al2O3: 14.04 %, Fe2O3: 16.01 %, MgO: 5.65 %, CaO: 7.58 % and TiO2: 3.59 %. There is an enrichment of LREE and a depletion of HREE. Based on the minerals, mineral chemistry and the geochemistry of the studied rock, the rock is mafic and hydrous minerals formed by hydration recrystallization of pyroxene. The rock has extensively retrogressed but has not been affected by any form of deformation.
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Mordberg, L. E., C. J. Stanley, and K. Germann. "Mineralogy and geochemistry of trace elements in bauxites: the Devonian Schugorsk deposit, Russia." Mineralogical Magazine 65, no. 1 (February 2001): 81–101. http://dx.doi.org/10.1180/002646101550145.
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AbstractProcesses of mineral alteration involving the mobilization and deposition of more than 30 chemical elements during bauxite formation and epigenesis have been studied on specimens from the Devonian Schugorsk bauxite deposit, Timan, Russia. Chemical analyses of the minerals were obtained by electron microprobe and element distribution in the minerals was studied by element mapping. Interpretation of these data also utilized high-resolution BSE and SE images.The main rock-forming minerals of the Vendian parent rock are calcite, dolomite, feldspar, aegirine, riebeckite, mica, chlorite and quartz; accessory minerals are pyrite, galena, apatite, ilmenite, monazite, xenotime, zircon, columbite, pyrochlore, chromite, bastnaesite and some others. Typically, the grainsize of the accessory minerals in both parent rock and bauxite is from 1 to 40 µm. However, even within these rather small grains, the processes of crystal growth and alteration during weathering can be determined from the zonal distribution of the elements. The most widespread processes observed are: (1) Decomposition of Ti-bearing minerals such as ilmenite, aegirine and riebeckite with the formation of ‘leucoxene’, which is the main concentrator of Nb, Cr, V and W. Crystal growth can be traced from the zonal distribution of Nb (up to 16 wt.%). Vein-like ‘leucoxene’ is also observed in association with organics. (2) Weathering of columbite and pyrochlore: the source of Nb in ‘leucoxene’ is now strongly weathered columbite, while the alteration of pyrochlore is expressed in the growth of plumbopyrochlore rims around Ca-rich cores. (3) Dissolution of sulphide minerals and apatite and the formation of crandallite group minerals: ‘crandallite’ crystals of up to 40 µm size show a very clear zonation. From the core to the rim of a crystal, the following sequence of elements is observed: Ca → Ba → Ce → Pb → Sr → Nd. Sulphur also shows a zoned but more complicated distribution, while the distribution of Fe is rather variable. A possible source of REE is bastnaesite from the parent rock. More than twelve crandallite type cells can be identified in a single ‘crandallite’ grain. (4) Alteration of stoichiometric zircon and xenotime with the formation of metamict solid solution of zircon and xenotime: altered zircon rims also bear large amounts of Sc (up to 3.5 wt.%), Fe, Ca and Al in the form of as yet unidentified inclusions of 1–2 µm. Monazite seems to be the least altered mineral of the profile.In the parent rock, an unknown mineral of the composition (wt.%): ThO2 – 54.8; FeO – 14.6; Y2O5 – 2.3; CaO – 2.0; REE – 1.8; SiO2 12.2; P2O5 – 2.8; total – 94.2 (average from ten analyses) was determined. In bauxite, another mineral was found, which has the composition (wt.%): ThO2 – 24.9; FeO – 20.5; Y2O5 – 6.7; CaO 2.0; – ZrO – 17.6; SiO2 – 8.8; P2O5 – 5.4; total – 89.3 (F was not analysed; average from nine analyses). Presumably, the second mineral is the result of weathering of the first one. Although the Th content is very high, the mineral is almost free of Pb. However, intergrowths of galena and pyrite are observed around the partially decomposed crystals of the mineral. Another generation of galena is enriched in chalcophile elements such as Cu, Cd, Bi etc., and is related to epigenetic alteration of the profile, as are secondary apatite and muscovite.
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Bulakh, A. G., A. R. Nesterov, C. T. Williams, and I. S. Anisimov. "Zirkelite from the Sebl'yavr carbonatite complex, Kola Peninsula, Russia: an X-ray and electron microprobe study of a partially metamict mineral." Mineralogical Magazine 62, no. 6 (December 1998): 837–46. http://dx.doi.org/10.1180/002646198548205.
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AbstractZirkelite, a cubic mineral of general formula (Ti,Ca,Zr)O2−x occurs as an accessory mineral in phoscorites, carbonatites and associated rocks in the Sebl'yavr complex. After pyrochlore, it is the main mineral concentrating niobium in these rocks. Zirkelite forms platy crystals comprising polysynthetic octahedral twins, often having a complex skeletal internal structure within a cuboctahedral external morphology. The mineral is largely metamict, but after heating to 800°C it produces a cubic crystalline structure with ao = 5.157 ±0.006 Å. It is black to brownish-black in colour, VHN = 760−780 kg.mm−2, density = 4.27 g.cm−3, and reflectance = 12.5%.Chemically, zirkelite is relatively enriched in Nb2O5 (up to 14.5 wt.%) and ThO2 (up to 7.7 wt.%), and it displays four compositionally-distinct zones which probably formed during primary crystallisation processes. It is patchily altered where it is associated with an unidentified Ba, Ti, Nb, Zr silicate phase which partly replaces and pseudomorphs it. Under the current IMA-approved nomenclature scheme, non-crystalline (metamict) minerals of the composition described here would normally be given the general species name zirconolite, with the name zirkelite confined to the cubic mineral. However, at Sebl'yavr, the name zirkelite is used because the mineral displays a well-defined cubic crystal morphology and has a cubic structure after heating.
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Zaitsev, Victor A., Nikita V. Chukanov, and Sergey M. Aksenov. "Chlorine-Deficient Analog of Taseqite from Odikhincha Massif (Russia): Genesis and Relation with Other Sr-Rich Eudialyte-Group Minerals." Minerals 12, no. 8 (August 12, 2022): 1015. http://dx.doi.org/10.3390/min12081015.
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Eudialyte-group minerals are important accessory minerals of peralkaline rocks of nepheline-syenite massifs and alkaline–ultramafic complexes. Here, we report the complex study of a eudialyte-group mineral (EGM) from peralkaline pegmatite of the alkaline-ultrabasic Odikhincha massif (Polar Siberia). The chemical composition of the studied EGM is intermediate between those of taseqite and eudialyte, with small admixtures of other members of the eudialyte group. The crystals of EGMs were formed during the postmagmatic stage in the temperature range of 300–350 °C and partly replaced by late eudialite along cracks during the zeolite stage (~230 °C). The chemical compositions, structural features and mineral association of the studied EGM are similar to those of Sr-Nb-dominant EGM found in other nepheline-syenite massifs, such as Khibiny, Lovozero and Pilansberg. The EGM studied in this work is a Cl-deficient taseqite variety (“monochlore taseqite”), which differs from “dichlorotaseqite” (found only in the Ilimaussaq massif) by a lower amount of chlorine.
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Raharjanti, N. A., I. W. Warmada, and H. T. B. M. Petrus. "Ore characterization of LSE gold deposit in “X” Pit, Toka Tindung Project, North Sulawesi." IOP Conference Series: Earth and Environmental Science 851, no. 1 (October 1, 2021): 012043. http://dx.doi.org/10.1088/1755-1315/851/1/012043.
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Abstract Toka Tindung Project is a low sulphidation epithermal gold deposit, which is located in North Sulawesi, Indonesia. To be able to maximize the production yield of the Toka Tin-dung Project, it is important to understand the characteristics of the ore along with its mineral associations. This paper discusses the ore characterization and its mineral associations in “X” pit using thin section analysis to define the rock characteristics and hydrothermal alteration, X-Ray Diffraction (XRD) to identify the hydrothermal alteration minerals, and ore microscopy to identify the type of ore minerals. The study area is occupied by three alteration zones, namely silicification, advanced argillic and intermediate argillic alteration. The silicification is characterized by quartz with accessory minerals such as kaolinite, smectite, and celadonite. The advanced argillic alteration is typified by kaolinite, with minor quartz. The intermediate argillic alteration is characterized by clay minerals such as illite, mixed illite/smectite, smectite, and minor quartz minerals. Mineralization in “X” pit is in the form of sheeted vein type quartz with colloform texture, and the ore minerals are found as sulfides such as pyrite and sphalerite.
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D’yachkov, Boris A., Ainel Y. Bissatova, Marina A. Mizernaya, Sergey V. Khromykh, Tatiana A. Oitseva, Oxana N. Kuzmina, Natalya A. Zimanovskaya, and Saltanat S. Aitbayeva. "Mineralogical Tracers of Gold and Rare-Metal Mineralization in Eastern Kazakhstan." Minerals 11, no. 3 (February 28, 2021): 253. http://dx.doi.org/10.3390/min11030253.
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Replenishment of mineral resources, especially gold and rare metals, is critical for progress in the mining and metallurgical industry of Eastern Kazakhstan. To substantiate the scientific background for mineral exploration, we study microinclusions in minerals from gold and rare-metal fields, as well as trace-element patterns in ores and their hosts that may mark gold and rare-metal mineralization. The revealed compositions of gold-bearing sulfide ores and a number of typical minerals (magnetite, goethite, arsenopyrite, antimonite, gold and silver) and elements (Fe, Mn, Cu, Pb, Zn, As, and Sb) can serve as exploration guides. The analyzed samples contain rare micrometer lead (alamosite, kentrolite, melanotekite, cotunnite) and nickel (bunsenite, trevorite, gersdorffite) phases and accessory cassiterite, wolframite, scheelite, and microlite. The ores bear native gold (with Ag and Pt impurities) amenable to concentration by gravity and flotation methods. Multistage rare-metal pegmatite mineralization can be predicted from the presence of mineral assemblages including cleavelandite, muscovite, lepidolite, spodumene, pollucite, tantalite, microlite, etc. and such elements as Ta, Nb, Be, Li, Cs, and Sn. Pegmatite veins bear diverse Ta minerals (columbite, tantalite-columbite, manganotantalite, ixiolite, and microlite) that accumulated rare metals late during the evolution of the pegmatite magmatic system. The discovered mineralogical and geochemical criteria are useful for exploration purposes.
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Dubyna, О., S. Kryvdik, V. Belskyy, and О. Vyshnevskyi. "ACCESSOR MINERALS OF RARE METALS IN THE GRORUDITES OF EASTERN AZOV (UKRAINE)." Visnyk of Taras Shevchenko National University of Kyiv. Geology, no. 2 (89) (2020): 36–41. http://dx.doi.org/10.17721/1728-2713.89.05.
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Unlike other Precambrian platforms and shields, alkaline granites and their hypabyssal and effusive variaties in Ukraine have limited distribution. In Eastern Azov region dike analogs of alkaline granites (grorudites) are known. They are different in chemical and mineral composition and considered as analogs of pantellerites (aegirine hihg-Ti) and comendites (amphibole low-Ti). The high-Ti aegirine grorudites are more intensively enriched with incompatible rare elements (REE, Zr, Nb) compared with their low-Ti varieties. Despite the high or elevated concentration of HFSE in grorudites, there are few of their own minerals in these rocks. Thus, in high-Ti grorudites there have been identified such minerals of rare elements as monazite-(Ce), bastnäsite-(Ce), britholite-like mineral and rare earth apatite, zircon and undiagnosed zirconium mineral, whereas only zircon and niobium-containing rutile are diagnosed in amphibole one. These minerals are very small in size, the largest of them can reach 15-20 μm (sometimes up to 50 μm), although most of them do not exceed 10 μm (usually 5-6 μm). It is assumed that a significant part of rare metals are isomorphically included in rock-forming minerals (alkaline pyroxenes and amphiboles), and zirconium minerals, at least part of them, are secondary and formed as result of changing of primary sodium (eudialyte, catapleite, ilerite) or calcium (gittingsite) zirconosilicates which are more typical for peralkaline (agpaitic) rocks. Taking into account the peculiarities of the mineral composition, geochemical features and rare-earth mineralization of the Azov region, there is reason to believe that the HFSE mineralization of these rocks is a consequence of the differentiation of the primary igneous silica unsaturated melt(s). Secondary hydrothermal processes are weakly manifested in the studied rocks and probably presented by replacement of primary accessory minerals. Elevated or high concentrations of Nb in high-Ti grorudites and absence of Nb-minerals may indicate that the PTcondition of differentiation of these rocks (low F concentration, high fO2, and hypabyssal conditions of crystallization) did not contribute to their crystallization. The presence of grorudites in this region increase the prospects of discovering small alkaline granite massifs (holocrystalline analogues of grorudites) to which deposits and/or occurrences of Nb, REE, Zr, Sn, Be can be related
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Kruk, Mikhail Nikolaevich, Anna Gennadievna Doroshkevich, Ilya Romanovich Prokopyev, and Ivan Aleksandrovich Izbrodin. "Mineralogy of Phoscorites of the Arbarastakh Complex (Republic of Sakha, Yakutia, Russia)." Minerals 11, no. 6 (May 24, 2021): 556. http://dx.doi.org/10.3390/min11060556.
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The Arbarastakh ultramafic carbonatite complex is located in the southwestern part of the Siberian Craton and contains ore-bearing carbonatites and phoscorites with Zr-Nb-REE mineralization. Based on the modal composition, textural features, and chemical compositions of minerals, the phoscorites from Arbarastakh can be subdivided into two groups: FOS 1 and FOS 2. FOS 1 contains the primary minerals olivine, magnetite with isomorphic Ti impurities, phlogopite replaced by tetraferriphlogopite along the rims, and apatite poorly enriched in REE. Baddeleyite predominates among the accessory minerals in FOS 1. Zirconolite enriched with REE and Nb and pyrochlore are found in smaller quantities. FOS 2 has a similar mineral composition but contains much less olivine, magnetite is enriched in Mg, and the phlogopite is enriched in Ba and Al. Of the accessory minerals, pyrochlore predominates and is enriched in Ta, Th, and U; baddeleyite is subordinate and enriched in Nb. Chemical and textural differences suggest that the phoscorites were formed by the sequential introduction of different portions of the melt. The melt that formed the FOS 1 was enriched in Zr and REE relative to the FOS 2 melt; the melt that formed the FOS 2 was enriched in Al, Ba, Nb, Ta, Th, U, and, to a lesser extent, Sr.
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Nemov, A. B. "Garnet-amphibole miaskites of the Ilmenogorsky miaskite massif (Southern Urals): Mineralogy and geochemistry." LITHOSPHERE (Russia) 20, no. 5 (October 30, 2020): 652–67. http://dx.doi.org/10.24930/1681-9004-2020-20-5-652-667.
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Research subject. This paper presents original findings about textural-structural, mineralogical, petrological, and geochemical features of the garnet-amphibole miaskites (firstes) of the Ilmenogorsky miaskite massif.Materials and methods. The microprobe analysis of mineral composition was performed using Tescan Vega3 sbu and REMMA202M scanning microscopes equipped with microanalyzers. The content of major, trace and rareearth elements (REE) in rock samples was determined by the methods of AAS and ICP-MS.Results. The garnet-amphibole miaskites under study are characterized by a rare mineral paragenesis, i.e. garnet-amphibole-pyroxene-nepheline-plagioclase. The mafic minerals exhibit a high ferruginosity (f = 70–99), while the accessory minerals have high Al, F and low REE contents. The garnetamphibole miaskites contains high concentrations of Al, Fe3+, Ca, Na, Be, Rb, Mo, Tl and low concentrations of LILE, HFSE, REE and transit elements.Conclusions. According to the garnet composition and its ferruginosity (f = 95– 99), high contents of Al and F in accessory minerals, the prevalence of Fe3+, as well as negative Eu/Eu* and positive Ce/ Ce* anomalies, the garnet-amphibole miaskites under study are assumed to be the product of acid-alkaline metasomatism occurring under the oxidizing conditions of petrogenesis. The low ratios of Cr/V and Ni/Co indicate the immobility of transit elements during metasomatism, and their clarke of concentration corresponds to the content in metaterrigenous and metacarbonate rocks, which suggests crustal substratum for garnet–amphibole miaskites. Garnet-amphibole miaskites are the markers of the interaction of crustal material with deep fluids, which occurred during the stage of shear tectonics development (270–240 Ma) due to the broad permeability of the rocks composing the Ilmenogorsky miaskite massif.
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Lougheed, H., M. McClenaghan, Daniel Layton-Matthews, Matthew Leybourne, and Agatha Dobosz. "Automated Indicator Mineral Analysis of Fine-Grained Till Associated with the Sisson W-Mo Deposit, New Brunswick, Canada." Minerals 11, no. 2 (January 21, 2021): 103. http://dx.doi.org/10.3390/min11020103.
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Exploration under thick glacial sediment cover is an important facet of modern mineral exploration in Canada and northern Europe. Till heavy mineral concentrate (HMC) indicator mineral methods are well established in exploration for diamonds, gold, and base metals in glaciated terrain. Traditional methods rely on visual examination of >250 µm HMC material. This study applies mineral liberation analysis (MLA) to investigate the finer (<250 µm) fraction of till HMC. Automated mineralogy (e.g., MLA) of finer material allows for the rapid collection of precise compositional and morphological data from a large number (10,000–100,000) of heavy mineral grains in a single sample. The Sisson W-Mo deposit has a previously documented dispersal train containing the ore minerals scheelite, wolframite, and molybdenite, along with sulfide and other accessory minerals, and was used as a test site for this study. Wolframite is identified in till samples up to 10 km down ice, whereas in previous work on the coarse fraction of till it was only identified directly overlying mineralization. Chalcopyrite and pyrite are found up to 10 km down ice, an increase over 2.5 and 5 km, respectively, achieved in previous work on the coarse fraction of the same HMC. Galena, sphalerite, arsenopyrite, and pyrrhotite are also found up to 10 km down ice after only being identified immediately overlying mineralization using the >250 µm fraction of HMC. Many of these sulfide grains are present only as inclusions in more chemically and robust minerals and would not be identified using optical methods. The extension of the wolframite dispersal train highlights the ability of MLA to identify minerals that lack distinguishing physical characteristics to aid visual identification.
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Ren, Minghua, and Xiang Wang. "Accessory Mineral Analysis of Alkali-rich Granite from Gejiu Tin District." Microscopy and Microanalysis 25, S2 (August 2019): 2322–23. http://dx.doi.org/10.1017/s1431927619012340.
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Domanik, Kenneth, Serena Kolar, Donald Musselwhite, and Michael J. Drake. "Accessory silicate mineral assemblages in the Bilanga diogenite: A petrographic study." Meteoritics & Planetary Science 39, no. 4 (April 2004): 567–79. http://dx.doi.org/10.1111/j.1945-5100.2004.tb00919.x.
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Gower, C. F., and P. Erdmer. "Proterozoic metamorphism in the Grenville Province: a study in the Double Mer – Lake Melville area, eastern Labrador." Canadian Journal of Earth Sciences 25, no. 11 (November 1, 1988): 1895–905. http://dx.doi.org/10.1139/e88-178.
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A regional metamorphic gradient from upper greenschist to granulite facies is identified south of the Grenville front in the Double Mer – Lake Melville area of eastern Labrador. Mineral assemblages in politic–granitic gneiss, amphibole-bearing quartzo-feldspathic gneiss, and coronitic metagabbro allow three major metamorphic domains to be established. These are collectively divisible into 11 subdomains. Geothermobarometry applied to the higher grade domains suggests that each is characterized by specific P–T conditions, which achieved 1000–1100 MPa and 700–800 °C in the deepest level rocks.The problem of reconciling geochronological data (which record a major orogenic event at 1650 Ma) with the occurrence of high-grade mineral assemblages in 1426 Ma metagabbro (which suggests a pervasive Grenvillian event) is discussed in terms of three models. The preferred model envisages crustal stabilization at 1650–1600 Ma to give high-grade mineral assemblages seen in the host rocks and with which mineral assemblages in coronitic metagabbro equilibrated after their emplacement at 1426 Ma. During Grenvillian orogenesis (1080–920 Ma) the present structural configuration was achieved by thrust stacking. This imparted a sporadic metamorphic and structural overprint and Grenvillian ages in selected accessory minerals.
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Tatarniuk, Dane M., Robin White, Rolf B. Modesto, and Kristina G. Miles. "Avulsion of the Accessory-Carpal Ligaments and Sagittal Fracture of the Ulnar Carpal Bone in a Foal." VCOT Open 02, no. 01 (January 2019): e50-e54. http://dx.doi.org/10.1055/s-0039-1692190.
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AbstractA 45-day-old foal presented for weight bearing lameness. Radiography revealed an abnormal radiolucent line associated with the proximal ulnar carpal bone and a separate curvilinear mineral opacity palmaromedial to the distal radial epiphysis. Computed tomography illustrated a sagittal, biarticular, non-displaced fracture of the ulnar carpal bone with small separate fragments associated with the accessory-ulnar and accessory-radial carpal ligaments. The foal was treated conservatively with rest and adjunct intra-articular hyaluronic acid. The lameness resolved within 90 days. Full range of motion of the carpus returned within 120 days following an active rehabilitation protocol. This report details avulsion of the accessory-carpal ligaments and sagittal fracture of the ulnar carpal bone secondary to presumed hyperextension injury.
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Timonina, N. N. "Material composition of Lower Triassic sandstones from the northern areas of the Timan-Pechora oil and gas province." Vestnik of Geosciences 9 (2020): 26–36. http://dx.doi.org/10.19110/geov.2020.9.5.
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Recently various authors paid much attention to accessory minerals of clastic rocks to clarify the composition of the source area and formation conditions of terrigenous deposits. The paper describes some minerals of the heavy fraction of Triassic sandstones in the north of the Timan-Pechora oil and gas province (garnet, epidote, chromium spinels, ilmenite, etc.). We showed that the enrichment of sandstones with various mineral grains was controlled by not only the composition of the eroded rocks, but also by the hydrodynamics of the flow, as well as the method of transfer of clastic material. We noted that the features of heavy fraction minerals could be used to reconstruct sedimentation environments, taking into account their physical and chemical properties, distribution of minerals by fractions, and their stability during transportation.
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Ulmanová, Jana, and Zdeněk Dolníček. "Minerály pegmatitových hnízd z okolí Jablonce nad Nisou (krkonošsko-jizerský pluton) - část I. silikáty." Bulletin Mineralogie Petrologie 28, no. 2 (2020): 466–82. http://dx.doi.org/10.46861/bmp.28.466.
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We have studied silicate minerals in pegmatite nests from the Tanvald Granite (4 sites) and the Liberec Granite (1 site) in the vicinity of Jablonec n. Nisou, situated within the Variscan Krkonoše-Jizera Pluton. They contain major quartz, K-feldspar and plagioclase (An0-11), subordinate biotite, muscovite and locally schorl. Accessory phases include garnet (spessartine-almandine), andalusite, Hf-rich zircon and thorite. In addition, zinnwaldite was found in a single sample. The studied pegmatites show simple internal structure including aplitic, granitic and coarse-grained “blocky” units; the central zone commonly contains miarolitic cavity which is sometimes filled by tourmaline. The mineral composition and fractionation degree largely reflect those of the host granite; the more fractionated are pegmatites hosted by the Tanvald Granite. The pegmatite nest from Nová Ves nad Nisou II exhibits distinct mineral assemblage with zinnwaldite, pure albite and lack of biotite and garnet, therefore we suggest here a substantial modification of mineral assemblage by superimposed processes. Moreover, tourmaline (schorl) composition with local increasing of Mg toward rim indicates a possible contamination derived from adjacent rocks during tourmaline crystallization.
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Strohmeier, B. R., K. L. Bunker, K. E. Harris, R. Hoch, and R. J. Lee. "The Database Solution to Particle-by-Particle Analysis of Mixed Mineral Dusts." Microscopy Today 15, no. 6 (November 2007): 44–47. http://dx.doi.org/10.1017/s1551929500061976.
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This work involves the development and application of a database for the morphological, crystallographic, and chemical characterization of amphibole particles that occur as accessory minerals in the former vermiculite mine in Libby, Montana. The data in the database were collected using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) techniques for particle-by-particle characterization of mixed mineral dust samples.In the fall of 1999, public attention was focused on the small town of Libby due to health concerns over potential amphibole asbestos exposure that occurred in the now closed vermiculite mine. The vermiculite deposit, located in the Rainy Creek Igneous Complex, about seven miles northeast of Libby, was discovered in 1913 and commercial production of vermiculite began in 1923.
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Mikhailova, Julia A., Yakov A. Pakhomovsky, Olga F. Goychuk, Andrey O. Kalashnikov, Ayya V. Bazai, and Victor N. Yakovenchuk. "Pre-Pegmatite Stage in Peralkaline Magmatic Process: Insights from Poikilitic Syenites from the Lovozero Massif, Kola Peninsula, Russia." Minerals 11, no. 9 (September 7, 2021): 974. http://dx.doi.org/10.3390/min11090974.
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The Lovozero peralkaline massif (Kola Peninsula, Russia) is widely known for its unique mineral diversity, and most of the rare metal minerals are found in pegmatites, which are spatially associated with poikilitic rocks (approximately 5% of the massif volume). In order to determine the reasons for this relationship, we have investigated petrography and the chemical composition of poikilitic rocks as well as the chemical composition of the rock-forming and accessory minerals in these rocks. The differentiation of magmatic melt during the formation of the rocks of the Lovozero massif followed the path: lujavrite → foyaite → urtite (magmatic stage) → pegmatite (hydrothermal stage). Yet, for peralkaline systems, the transition between magmatic melt and hydrothermal solution is gradual. In the case of the initially high content of volatiles in the melt, the differentiation path was probably as follows: lujavrite → foyaite (magmatic stage) → urtitization of foyaite → pegmatite (hydrothermal stage). Poikilitic rocks were formed at the stage of urtitization, and we called them pre-pegmatites. Indeed, the poikilitic rocks have a metasomatic texture and, in terms of chemical composition, correspond to magmatic urtite. The reason for the abundance of rare metal minerals in pegmatites associated with poikilitic rocks is that almost only one nepheline is deposited during urtitization, whereas during the magmatic crystallization of urtite, rare elements form accessory minerals in the rock and are less concentrated in the residual solution.
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Williams, M. L., and M. J. Jercinovic. "Application of Electron Microprobe Age Mapping and Dating of Monazite." Microscopy and Microanalysis 6, S2 (August 2000): 406–7. http://dx.doi.org/10.1017/s1431927600034528.
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High resolution X-ray mapping and dating of monazite (Th, REE-phosphate) using the electron microprobe is an exceptionally powerful technique for structural, metamorphic, and tectonic analysis in geology. Age determination of geologic materials has been conventionally accomplished by mass spectrometry-based analysis of radioisotopic ratios in minerals from hand-picked mineral separates, careful sampling of individual grains out of petrographic thin sections, or by detailed ion probe analysis. Recently, use of the electron microprobe for dating purposes has been attempted. In principal, the concentrations of Th, U and Pb uniquely define the age if non-radiogenic Pb is either not initially present or can be subtracted from the total Pb. Monazite contains high concentrations of Th and U and does not appear to incorporate significant non-radiogenic Pb during mineral growth. Furthermore, monazite is a ubiquitous accessory phase in many metamorphic and igneous rocks, making it ideal for microprobe dating.