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Eizou Nakamura - One of the best experts on this subject based on the ideXlab platform.
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determination of 17o excess of terrestrial silicate Oxide Minerals with respect to vienna standard mean ocean water vsmow
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ryoji Tanaka, Eizou NakamuraAbstract:RATIONALE Oxygen triple isotope compositions give key information for understanding physical processes during isotopic fractionation between the geo-, hydro-, bio-, and atmosphere. For detailed discussion of these topics, it is necessary to determine precise (17)O-excess values of terrestrial silicate/Oxide Minerals with respect to Vienna Standard Mean Ocean Water (VSMOW). METHODS Water was fluorinated in an electrically heated Ni-metal tube into which water and BrF(5) were loaded for the quantitative extraction of oxygen. Silicate/Oxide Minerals were fluorinated by heating with a CO(2) laser in an atmosphere of BrF(5). The extracted oxygen was purified and isotope ratios of the oxygen triple isotope compositions were determined using a Finnigan MAT253 isotope ratio mass spectrometer. RESULTS The oxygen triple isotope compositions of meteoric water and terrestrial silicate/Oxide Minerals fall on statistically distinguishable fractionation lines, defined as [ln(δ(17)O + 1) = λln(δ(18) O + 1) + Δ], where λ and Δ correspond to the slope and intercept, respectively. The fractionation line for meteoric water has λ = 0.5285 ± 0.0005 and Δ = 0.03 ± 0.02‰ and for terrestrial silicate/Oxide Minerals has λ = 0.5270 ± 0.0005 and Δ = -0.070 ± 0.005‰, at the 95% confidence limit. CONCLUSIONS All the analyzed terrestrial silicate/Oxide Minerals including internationally accepted reference materials (NBS-28, UWG-2, and San Carlos olivine) have a negative (17)O-excess with respect to VSMOW. We propose that it is necessary to specify if the determined δ(17)O values of terrestrial and extraterrestrial samples are expressed as the difference from VSMOW or the terrestrial silicate mineral-corrected value.
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Determination of 17O-excess of terrestrial silicate/Oxide Minerals with respect to Vienna Standard Mean Ocean Water (VSMOW).
Rapid Communications in Mass Spectrometry, 2012Co-Authors: Ryoji Tanaka, Eizou NakamuraAbstract:RATIONALE Oxygen triple isotope compositions give key information for understanding physical processes during isotopic fractionation between the geo-, hydro-, bio-, and atmosphere. For detailed discussion of these topics, it is necessary to determine precise (17)O-excess values of terrestrial silicate/Oxide Minerals with respect to Vienna Standard Mean Ocean Water (VSMOW). METHODS Water was fluorinated in an electrically heated Ni-metal tube into which water and BrF(5) were loaded for the quantitative extraction of oxygen. Silicate/Oxide Minerals were fluorinated by heating with a CO(2) laser in an atmosphere of BrF(5). The extracted oxygen was purified and isotope ratios of the oxygen triple isotope compositions were determined using a Finnigan MAT253 isotope ratio mass spectrometer. RESULTS The oxygen triple isotope compositions of meteoric water and terrestrial silicate/Oxide Minerals fall on statistically distinguishable fractionation lines, defined as [ln(δ(17)O + 1) = λln(δ(18) O + 1) + Δ], where λ and Δ correspond to the slope and intercept, respectively. The fractionation line for meteoric water has λ = 0.5285 ± 0.0005 and Δ = 0.03 ± 0.02‰ and for terrestrial silicate/Oxide Minerals has λ = 0.5270 ± 0.0005 and Δ = -0.070 ± 0.005‰, at the 95% confidence limit. CONCLUSIONS All the analyzed terrestrial silicate/Oxide Minerals including internationally accepted reference materials (NBS-28, UWG-2, and San Carlos olivine) have a negative (17)O-excess with respect to VSMOW. We propose that it is necessary to specify if the determined δ(17)O values of terrestrial and extraterrestrial samples are expressed as the difference from VSMOW or the terrestrial silicate mineral-corrected value.
Ryoji Tanaka - One of the best experts on this subject based on the ideXlab platform.
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determination of 17o excess of terrestrial silicate Oxide Minerals with respect to vienna standard mean ocean water vsmow
Rapid Communications in Mass Spectrometry, 2013Co-Authors: Ryoji Tanaka, Eizou NakamuraAbstract:RATIONALE Oxygen triple isotope compositions give key information for understanding physical processes during isotopic fractionation between the geo-, hydro-, bio-, and atmosphere. For detailed discussion of these topics, it is necessary to determine precise (17)O-excess values of terrestrial silicate/Oxide Minerals with respect to Vienna Standard Mean Ocean Water (VSMOW). METHODS Water was fluorinated in an electrically heated Ni-metal tube into which water and BrF(5) were loaded for the quantitative extraction of oxygen. Silicate/Oxide Minerals were fluorinated by heating with a CO(2) laser in an atmosphere of BrF(5). The extracted oxygen was purified and isotope ratios of the oxygen triple isotope compositions were determined using a Finnigan MAT253 isotope ratio mass spectrometer. RESULTS The oxygen triple isotope compositions of meteoric water and terrestrial silicate/Oxide Minerals fall on statistically distinguishable fractionation lines, defined as [ln(δ(17)O + 1) = λln(δ(18) O + 1) + Δ], where λ and Δ correspond to the slope and intercept, respectively. The fractionation line for meteoric water has λ = 0.5285 ± 0.0005 and Δ = 0.03 ± 0.02‰ and for terrestrial silicate/Oxide Minerals has λ = 0.5270 ± 0.0005 and Δ = -0.070 ± 0.005‰, at the 95% confidence limit. CONCLUSIONS All the analyzed terrestrial silicate/Oxide Minerals including internationally accepted reference materials (NBS-28, UWG-2, and San Carlos olivine) have a negative (17)O-excess with respect to VSMOW. We propose that it is necessary to specify if the determined δ(17)O values of terrestrial and extraterrestrial samples are expressed as the difference from VSMOW or the terrestrial silicate mineral-corrected value.
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Determination of 17O-excess of terrestrial silicate/Oxide Minerals with respect to Vienna Standard Mean Ocean Water (VSMOW).
Rapid Communications in Mass Spectrometry, 2012Co-Authors: Ryoji Tanaka, Eizou NakamuraAbstract:RATIONALE Oxygen triple isotope compositions give key information for understanding physical processes during isotopic fractionation between the geo-, hydro-, bio-, and atmosphere. For detailed discussion of these topics, it is necessary to determine precise (17)O-excess values of terrestrial silicate/Oxide Minerals with respect to Vienna Standard Mean Ocean Water (VSMOW). METHODS Water was fluorinated in an electrically heated Ni-metal tube into which water and BrF(5) were loaded for the quantitative extraction of oxygen. Silicate/Oxide Minerals were fluorinated by heating with a CO(2) laser in an atmosphere of BrF(5). The extracted oxygen was purified and isotope ratios of the oxygen triple isotope compositions were determined using a Finnigan MAT253 isotope ratio mass spectrometer. RESULTS The oxygen triple isotope compositions of meteoric water and terrestrial silicate/Oxide Minerals fall on statistically distinguishable fractionation lines, defined as [ln(δ(17)O + 1) = λln(δ(18) O + 1) + Δ], where λ and Δ correspond to the slope and intercept, respectively. The fractionation line for meteoric water has λ = 0.5285 ± 0.0005 and Δ = 0.03 ± 0.02‰ and for terrestrial silicate/Oxide Minerals has λ = 0.5270 ± 0.0005 and Δ = -0.070 ± 0.005‰, at the 95% confidence limit. CONCLUSIONS All the analyzed terrestrial silicate/Oxide Minerals including internationally accepted reference materials (NBS-28, UWG-2, and San Carlos olivine) have a negative (17)O-excess with respect to VSMOW. We propose that it is necessary to specify if the determined δ(17)O values of terrestrial and extraterrestrial samples are expressed as the difference from VSMOW or the terrestrial silicate mineral-corrected value.
Petr Cerny - One of the best experts on this subject based on the ideXlab platform.
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Primary Oxide Minerals in the system WO3-Nb2O5-TiO2-Fe2O3-FeO and their breakdown products from the pegmatite No. 3 at Dolní Bory-Hatě, Czech Republic
European Journal of Mineralogy, 2017Co-Authors: Milan Novák, Vladimir Srein, Zdenek Johan, Petr Cerny, Radek Škoda, Frantsiek VeselovskyAbstract:Symmetrically zoned barren pegmatite dike No. 3 cuts granulite at Dolní Bory-Hatě in the Czech Republic. It contains minor to accessory biotite, schorl, muscovite, sekaninaite, andalusite, diaspore, apatite and several rare accessory Minerals. Black, tabular crystals of ferberite-"wolframoixiolite" occur almost exclusively in an andalusite-diaspore aggregate with sequential accumulations of late pyrophyllite, kaolinite, and muscoviteillite. Complex zoning of the individual crystals of ferberite-"wolframoixiolite" shows primary, coarse oscillatory zoning consisting of narrow zones of ferberite (5.01-6.00 apfu W) and dominant niobian ferberite I (5.00-3.01 apfu W) to "wolframoixiolite" (< 3.00 apfu W), the latter two phases with very fine oscillatory internal zoning. The primary phases were locally replaced by a fine-grained mixture of ferberite to niobian ferberite II > tungstenian-titanian ferrocolumbite >> niobian and tungstenian rutile > ScPO4 phase > scheelite. Primary and secondary phases are characterized by large variation in W/(W+Nb+Ta) and calculated Fe2+/(Fe2++Fe3+) but low and almost constant Mn/(Mn+Fetot) and Ta/(Ta+Nb). The contents of P, U, Ti, Zr, Si, Sc, Al and Ca vary from negligible in ferberite to minor in "wolframoixiolite" and its U-rich variety: UO2 2.71 (19.82 U-rich variety), P2O5 0.30, TiO2 4.81, ZrO2 2.84, SiO2 0.93, Sc2O3 4.36, Al2O3 0.87, CaO 1.02 (all in wt.%). The combined exchange vector: (R3+)8(R4+)6(R5+)16(R2+)−13(R6+)−17, where R2+ = Fe2+ > Mn, Ca; R3+ = Fe3+ > Sc, Al; R4+ = Ti > Zr, Si, U; R5+ = Nb > Ta, P; R6+ = W, seems to be the best expression of the actual substitution mechanism from ferberite to "wolframoixiolite" with the theoretical end composition (R2+1.1R3+3.4R4+1.9R5+5.6)∑12O24. The homovalent substitutions expressed by the exchange vectors: Fe2+Mn−1, TaNb−1 and ScFe3+−1 are rather negligible. Formation of primary W, Nb, Fe-Oxide Minerals is closely related to the assemblage andalusite+diaspore, formed at T < ~ 400 °C for P = 2 kbar. The breakdown process probably proceeded at slightly lower temperatures of about 350-300 °C. Textural relations of the breakdown products characterized by the total absence of any depleted primary phase in the BSE images indicate that the secondary assemblage did not originated from an exsolution-type process. Complete recrystallization and reconstitution of the primary Minerals seems to be responsible for its origin. The chemical composition of the primary niobian ferberite to "wolframoixiolite" from Dolní Bory-Hatě is distinct from all other W-rich Nb,Ta-Oxide Minerals described to date except niobian wolframite from the granitic pegmatite at Nuaparra, Mozambique.
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geochemistry of Oxide Minerals of nb ta sn and sb in the varutrask granitic pegmatite sweden the case of an anomalous columbite tantalite trend
American Mineralogist, 2004Co-Authors: Petr Cerny, Ron Chapman, Karen Ferreira, Stenanders SmedsAbstract:The complex, petalite-subtype Varutrask pegmatite in the Proterozoic rocks of northern Sweden is, as a whole, rather poor in Nb and Ta. The pegmatite consolidated in eight units, but the (Nb,Ta)-Oxide Minerals attained saturation levels only in a late albite + lepidolite-bearing unit under conditions of high activity of alkali fluorides. Consequently, the compositional trends of columbite-group Minerals and cassiterite mimic those typically displayed in pegmatites of the lepidolite subtype: from ferroan manganocolumbite [with Mn/(Mn + Fe)(at.) of 0.35 and Ta/(Ta + Nb) of 0.08] through near-end-member manganocolumbite (0.95 and 0.20, respectively) to Fe-depleted manganotantalite (0.99 and 0.55, respectively), and from (Fe ≫ Mn, Nb > Ta)-bearing to (Mn > Fe, Ta > Nb)-enriched cassiterite. To date, rare occurrences of cassiterite with Mn > Fe are restricted solely to the lepidolite-enriched granitic pegmatites. The degree of cation order in the Varutrask columbite-group Minerals increases from early to late phases, and with decreasing amounts of heterovalent substitutions. Slower cooling of initially disordered structures in late phases, or their diminished compositional complexity may be responsible for the higher degree of order. Rare primary microinclusions of cassiterite in columbite-group Minerals show consistent and systematic preference for Ta and Fe, suggesting an approach to chemical equilibrium, but columbite-group inclusions in cassiterite show in part a compositional scatter. In contrast, rare inclusions of ferrotapiolite and wodginite closely reflect the (Fe, Mn, Ta, Nb) compositional features of the host cassiterite. Stibiotantalite shows high values of Ta/(Ta + Nb) and mere traces of Bi, reflecting the relative abundance of native antimony and stibarsen in the pegmatite, and the absence of Bi-bearing Minerals. Rare primary microlite is Ta- and F-rich, whereas the more widespread pyrochlore-microlite metasomatic after columbite-group Minerals reflects the Ta/(Ta + Nb) values of the precursors, as does the stibiomicrolite replacing stibiotantalite. Cesium is elevated in several grains of primary and metasomatic pyrochlore-group phases that also are enriched in Sb, but not in stibiomicrolite. The array of large cations in pyrochlore-microlite metasomatic after columbite-group Minerals is quite different from that typical of stibiomicrolite, suggestive of differences in the nature of the parent fluids. The lepidolite-subtype signature of the columbite-group Minerals and cassiterite in the petalite-subtype Varutrask pegmatite emphasizes the importance of specific conditions controlling stabilization of these Minerals. The restriction of the columbite-group Minerals to a very late lepidoliterich unit imposes a lepidolite-subtype signature on the whole petalite-subtype pegmatite, a signature grossly different from the characteristics typical of petalite-subtype pegmatites elsewhere.
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NIOBIUM-TANTALUM Oxide Minerals FROM COMPLEX GRANITIC PEGMATITES IN THE MOLDANUBICUM, CZECH REPUBLIC : PRIMARY VERSUS SECONDARY COMPOSITIONAL TRENDS
Canadian Mineralogist, 1998Co-Authors: Milan Novák, Petr CernyAbstract:Compositional trends of Nb, Ta-Oxide Minerals in four complex granitic pegmatites (lepidolite and petalite subtypes) in the Moldanubicum, Czech Republic, covering primary (magmatic) and secondary (hydrothermal replacement) stages of crystallization, were investigated. The primary stage is characterized by ferrocolumbite to manganocolumbite, followed after Fe- and Mn-depletion by Ca- or Sb-rich Minerals: microlite (Nova Ves), rynersonite (Chvalovice) and stibiotantalite (Dobra Voda, Lastovicky). Compositional paths in columbite are similar to those of lepidolite pegmatites; the other primary Nb, Ta-Oxide Minerals exhibit Ta/(Ta+Nb) values significantly higher relative to columbite. Decreasing Nb/Ta and the cation sequence Fe-Mn-(Sb,Ca) are typical of the primary stage. The secondary stage displays a broad spectrum of mainly fracture-filling secondary phases, such as diverse microlite-group Minerals, cesstibtantite, manganotantalite, ferrotantalite and ferrotapiolite, which replace stibiotantalite, microlite and rynersonite; columbite in outer pegmatite units remains unaffected. The Ta/(Ta+Nb) values of the secondary phases are comparable to those of their precursors. The general sequence of major A-site cations in hydrothermal Nb, Ta-Oxide Minerals, (Sb)-Ca-Mn-Fe, is reversed relative to that of the primary stage, and it may represent a universal pattern of hydrothermal replacement of primary Nb, Ta-Oxide Minerals in comparable granitic pegmatites. The composition of microlite-type Minerals and textural relations indicate that the secondary hydrothermal stage includes a broad range of P-T-X conditions from early subsolidus replacement at approximately 500-350 degrees C, approximately 2.5-2.0 kbar (Nova Ves, Dobra Voda) to near-surface weathering at
Kazuya Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Iron-Oxide Minerals affect extracellular electron-transfer paths of Geobacter spp.
Microbes and Environments, 2013Co-Authors: Souichiro Kato, Kazuhito Hashimoto, Kazuya WatanabeAbstract:Some bacteria utilize (semi)conductive iron-Oxide Minerals as conduits for extracellular electron transfer (EET) to distant, insoluble electron acceptors. A previous study demonstrated that microbe/mineral conductive networks are constructed in soil ecosystems, in which Geobacter spp. share dominant populations. In order to examine how (semi)conductive iron-Oxide Minerals affect EET paths of Geobacter spp., the present study grew five representative Geobacter strains on electrodes as the sole electron acceptors in the absence or presence of (semi)conductive iron Oxides. It was found that iron-Oxide Minerals enhanced current generation by three Geobacter strains, while no effect was observed in another strain. Geobacter sulfurreducens was the only strain that generated substantial amounts of currents both in the presence and absence of the iron Oxides. Microscopic, electrochemical and transcriptomic analyses of G. sulfurreducens disclosed that this strain constructed two distinct types of EET path; in the absence of iron-Oxide Minerals, bacterial biofilms rich in extracellular polymeric substances were constructed, while composite networks made of mineral particles and microbial cells (without polymeric substances) were developed in the presence of iron Oxides. It was also found that uncharacterized c-type cytochromes were up-regulated in the presence of iron Oxides that were different from those found in conductive biofilms. These results suggest the possibility that natural (semi)conductive Minerals confer energetic and ecological advantages on Geobacter, facilitating their growth and survival in the natural environment.
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methanogenesis facilitated by electric syntrophy via semi conductive iron Oxide Minerals
Environmental Microbiology, 2012Co-Authors: Souichiro Kato, Kazuya Watanabe, Kazuhito HashimotoAbstract:Summary Methanogenesis is an essential part of the global carbon cycle and a key bioprocess for sustainable energy. Methanogenesis from organic matter is accomplished by syntrophic interactions among different species of microbes, in which interspecies electron transfer (IET) via diffusive carriers (e.g. hydrogen and formate) is known to be the bottleneck step. We report herein that the supplementation of soil microbes with (semi)conductive iron-Oxide Minerals creates unique interspecies interactions and facilitates methanogenesis. Methanogenic microbes were enriched from rice paddy field soil with either acetate or ethanol as a substrate in the absence or presence of (semi)conductive iron Oxides (haematite or magnetite). We found that the supplementation with either of these iron Oxides resulted in the acceleration of methanogenesis in terms of lag time and production rate, while the supplementation with an insulative iron Oxide (ferrihydrite) did not. Clone-library analyses of 16S rRNA gene fragments PCR-amplified from the enrichment cultures revealed that the iron-Oxide supplementation stimulated the growth of Geobacter spp. Furthermore, the addition of a specific inhibitor for methanogenesis suppressed the growth of Geobacter spp. These results suggest that Geobacter grew under syntrophic association with methanogens, and IET could occur via electric currents through (semi)conductive iron-Oxide Minerals (termed ‘electric syntrophy’). Given the ubiquity of conductive Minerals in nature, such energetic interactions may occur widely in soil and sediments and can be used to develop efficient bioenergy processes.
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Methanogenesis facilitated by electric syntrophy via (semi)conductive iron‐Oxide Minerals
Environmental Microbiology, 2011Co-Authors: Souichiro Kato, Kazuhito Hashimoto, Kazuya WatanabeAbstract:Summary Methanogenesis is an essential part of the global carbon cycle and a key bioprocess for sustainable energy. Methanogenesis from organic matter is accomplished by syntrophic interactions among different species of microbes, in which interspecies electron transfer (IET) via diffusive carriers (e.g. hydrogen and formate) is known to be the bottleneck step. We report herein that the supplementation of soil microbes with (semi)conductive iron-Oxide Minerals creates unique interspecies interactions and facilitates methanogenesis. Methanogenic microbes were enriched from rice paddy field soil with either acetate or ethanol as a substrate in the absence or presence of (semi)conductive iron Oxides (haematite or magnetite). We found that the supplementation with either of these iron Oxides resulted in the acceleration of methanogenesis in terms of lag time and production rate, while the supplementation with an insulative iron Oxide (ferrihydrite) did not. Clone-library analyses of 16S rRNA gene fragments PCR-amplified from the enrichment cultures revealed that the iron-Oxide supplementation stimulated the growth of Geobacter spp. Furthermore, the addition of a specific inhibitor for methanogenesis suppressed the growth of Geobacter spp. These results suggest that Geobacter grew under syntrophic association with methanogens, and IET could occur via electric currents through (semi)conductive iron-Oxide Minerals (termed ‘electric syntrophy’). Given the ubiquity of conductive Minerals in nature, such energetic interactions may occur widely in soil and sediments and can be used to develop efficient bioenergy processes.
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respiratory interactions of soil bacteria with semi conductive iron Oxide Minerals
Environmental Microbiology, 2010Co-Authors: Souichiro Kato, Ryuhei Nakamura, Kazuya Watanabe, Kazuhito HashimotoAbstract:Summary Pure-culture studies have shown that dissimilatory metal-reducing bacteria are able to utilize iron-Oxide nanoparticles as electron conduits for reducing distant terminal acceptors; however, the ecological relevance of such energy metabolism is poorly understood. Here, soil microbial communities were grown in electrochemical cells with acetate as the electron donor and electrodes (poised at 0.2 V versus Ag/AgCl) as the electron acceptors in the presence and absence of iron-Oxide nanoparticles, and respiratory current generation and community structures were analysed. Irrespective of the iron-Oxide species (hematite, magnetite or ferrihydrite), the supplementation with iron-Oxide Minerals resulted in large increases (over 30-fold) in current, while only a moderate increase (∼10-fold) was observed in the presence of soluble ferric/ferrous irons. During the current generation, insulative ferrihydrite was transformed into semiconductive goethite. Clone-library analyses of 16S rRNA gene fragments PCR-amplified from the soil microbial communities revealed that iron-Oxide supplementation facilitated the occurrence of Geobacter species affiliated with subsurface clades 1 and 2. We suggest that subsurface-clade Geobacter species preferentially thrive in soil by utilizing (semi)conductive iron Oxides for their respiration.
T. Rodemann - One of the best experts on this subject based on the ideXlab platform.
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Polymineralic inclusions in Oxide Minerals of the Afrikanda alkaline-ultramafic complex: Implications for the evolution of perovskite mineralisation
Contributions to Mineralogy and Petrology, 2020Co-Authors: N. J. Potter, V. S. Kamenetsky, A. R. Chakhmouradian, M. B. Kamenetsky, K. Goemann, T. RodemannAbstract:The exceptional accumulation of perovskite in the alkaline-ultramafic Afrikanda complex (Kola Peninsula, Russia) led to the study of polymineralic inclusions hosted in perovskite and magnetite to understand the development of the perovskite-rich zones in the olivinites, clinopyroxenites and silicocarbonatites. The abundance of inclusions varies across the three perovskite textures, with numerous inclusions hosted in the fine-grained equigranular perovskite, fewer inclusions in the coarse-grained interlocked perovskite and rare inclusions in the massive perovskite. A variety of silicate, carbonate, sulphide, phosphate and Oxide phases are assembled randomly and in variable proportions in the inclusions. Our observations reveal that the inclusions are not bona fide melt inclusions. We propose that the inclusions represent material trapped during subsolidus sintering of magmatic perovskite. The continuation of the sintering process resulted in the coarsening of inclusion-rich subhedral perovskite into inclusion-poor anhedral and massive perovskite. These findings advocate the importance of inclusion studies for interpreting the origin of Oxide Minerals and their associated economic deposits and suggest that the formation of large scale accumulations of Minerals in other Oxide deposits may be a result of annealing of individual disseminated grains.
