Composition Of Inclusions Research Articles

Composition of volatiles of sulfide deposits and carbonate structures in submarine hydrothermal fields of the Mid-Atlantic Ridge

In this study, the composition of fluid inclusions in minerals from polymetallic sulfide deposits Ashadze-1, Semenov-2, Krasnov, Rainbow and from the Lost City carbonate structures of hydrothermal fields in the Atlantic Ocean was determined using pyrolysis-free gas chromatography–mass spectrometry.It was found out that sulfides and anhydrite from the hydrothermal ore crystallized in reducing conditions with the active participation of hydrocarbons, including high-molecular, sulfonated, nitrogenated and halogenated compounds as well as water and carbon dioxide.On the other hand, carbonate structures formed in considerably more oxidizing conditions, for which the main components of volatiles were СО2 and Н2О. The amount of detected hydrocarbons, including sulfonated, nitrogenated and halogenated compounds is significantly smaller compared to sulfides of ore vent structures.

Non-metallic inclusions interpretation technique for factory expertise of metal product defects

The technique of processing the results of factory experts’ reports has been developed to interpret the origin of nonmetallic inclusions (NMIs) detected in the defects of a welded pipe joints made of J55 API 5L (22GYu) steel. Thermodynamic simulation was performed to assess the possibility of the indigenous origin of these inclusions. The results of such a simulation were summarized using radar diagrams of four clusters uniting NMIs with similar composition of deoxidation and modification products. More than 130 compositions of actual inclusions detected on dozens of welded joints samples were processed and combined into four clusters in the same way. After a comparative analysis of these two types of radar diagrams, the origin of all clusters of actual inclusions was established, three of which are predominantly exogenous inclusions and the fourth is predominantly indigenous. None of the clusters contains only indigenous inclusions or only exogenous ones. The main source of inclusions in the discontinuities of welded joints is inclusions conglomerates, sorbed on the refractories surface, contacted with molten steel during its ladle treatment and pouring. These sintered conglomerates of indigenous and exogenous inclusions, that form three clusters of four ones, were out washed by the flow of steel melt into the crystallizer during steel pouring. The reasons for the formation of the fourth cluster are related to “cold welding”. The technique is implemented as a plug-in of Thixomet Pro image analysis system and allows to automate the process of metallographic conclusions generation in factory practice, as well as to accumulate all information in a database for its subsequent processing and analysis.

Compositional modification of nonmetallic inclusions in bloomery iron during post‐smelting treatments and its implication

AbstractThe chemical composition of nonmetallic inclusions in finished iron artifacts often holds key information on the smelting and post‐smelting processes applied during their production. This possibility was tested with special iron objects deemed product intermediaries from a royal tomb constructed at Gyongju, the former capital of the Silla state during the Korean Three Kingdoms period (c. 300–668 ce). Metallographic examination identified two distinct groups of inclusions with features unique to slags derived from smelting in (a) bloomery furnaces and (b) blast furnaces. Clear evidence was also noted that type ‘a’ inclusions, when subjected to an environment of high carbon activity as in a carburization process, underwent a significant change in chemical composition and microstructure to emulate the other type. This observation is expected to remove significant ambiguities encountered in connecting slag compositions to pertinent engineering processes.

Using ToF-SIMS analyses for analysing individual oil inclusions of different fluorescence colours in a single quartz crystal from the Barrandian (Czech Republic)

The fluorescence colour and molecular signature of oil inclusions can provide precious information on the thermal maturity of inclusion oils and the fluid migration history of basins. Here we show how molecular mass spectrometric analyses in combination with fluorescence microscopy can be used to reveal heterogeneities in the chemical compositions of oil inclusions within a micrometer sized quartz crystal. We used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to extract and directly analyse the molecular content of two yellow and two white-blue fluorescing oil inclusions in a single quartz crystal from the Barrandian Basin (Czech Republic). The cyclic ion species detected primarily in the yellow fluorescing oil inclusions likely originate from steranes, hopanes, and other tricyclic and tetracyclic terpanes, whereas these are less abundant in the white-blue fluorescing oil inclusions. Depth profiles of the fluid inclusions indicate that the white-blue fluorescing oil inclusions are emptied faster in the ToF-SIMS instrument, presumably due to a higher content of more volatile components than in the yellow fluorescing oil inclusions. The phenanthrene to dibenzothiophene ratio derived from ToF-SIMS of the four inclusion oils from the Barrandian Basin indicates marine clastic sediments as the source rocks for all the inclusion oils. The phenanthrene to alkylphenanthrene ratio derived from ToF-SIMS indicates no major difference in thermal maturity of the oil in the white-blue and yellow fluorescing oil inclusions. Instead, variation in the chemical content of the trapped oil induced by trapping fractionation may be the key control.

An exploration of whether Earth can be built from chondritic components, not bulk chondrites

Here, two of a range of possible models are explored that assume that: (i) two of the main chondritic components (chondrules and refractory inclusions) dominated the Earth’s building blocks, (ii) that their relative abundances differed from those of known chondrites, and (iii) that the elemental compositions of all components, as well as the isotopic compositions of refractory inclusions, resembled those of the components in carbonaceous chondrites.In terms of the elemental abundances, the chondrules can explain the moderately volatile element fractionations in the Bulk Silicate Earth (BSE), except for a few elements like F and In, while the refractory inclusions explain the BSE’s refractory lithophile element enrichment. Accretion of a CM- or EL-like late veneer reproduces the S, Se, Te and highly siderophile element abundances in the BSE. The accretion of CI- or CM-like material prior to the late veneer, along with small amounts of cometary and implanted solar wind material, can explain the BSE elemental and isotopic abundances of the noble gases as well as the elemental abundances of most other highly volatile elements (e.g., H, C and N) provided that variable fractions of them can be sequestered into the core or into hidden mantle reservoirs. This CI- or CM-like material provides an upper limit for the contribution to the BSE from matrix that is much less than in any chondrites. In the models, Si, O and S are the dominant light elements in the core, in that order, and their abundances are constrained to be consistent with the first principles calculations of Umemoto and Hirose (2020). The core compositions of the models are also consistent with most geochemical constraints.Satisfying all isotopic constraints is a challenge. The BSE Os isotopes are consistent with an EL dominated late veneer, but Ru isotopic evidence is best explained by the addition of CM-like material in the late veneer. Either CI- or CM-like material, in combination with small amounts of cometary and implanted solar wind material, can reproduce the BSE Ne, Ar and Kr isotopic compositions. CM-like, but not CI-like, material can roughly reproduce the BSE’s H and C isotopic compositions, but neither material can explain the BSE N isotopic composition. The BSE composition requires that the O isotopic compositions of the refractory inclusions (initially Δ17O ≤ −20‰) in Earth’s building blocks were reset in the nebula by interaction with high Δ17O H2O, perhaps during chondrule formation. To plot on the inner Solar System ε54Cr vs. ε50Ti (or ε48Ca) trend, either the average Cr content of the chondrules was roughly half of that assumed here or most of the CI/CM-like and refractory-inclusion-rich materials were accreted late.

Mathematical modeling of pyroxene-magnetite crystalline shales elastic and acoustic properties

The analysis of the results of mathematical modeling of the influence of the format, mineral concentration and fracture of metamorphic crystalline shales of the Pishcha iron ore structure is presented. The aim of this work is to analyze the influence of mineral composition, types, orientation and concentration of mineral inclusions and microcracks on the acoustic and elastic properties of a group of samples of “quartz-magnetite-pyroxene” crystalline shales of Pishchans’ka iron ore structure. Based on the method of conditional moments, mathematical modeling of the influence of the format, orientation and content of mineral grains, as well as the concentration and format of cracking on the acoustic and elastic properties of rocks of the Pishchans`ka iron ore structure was performed. According to the obtained data, a weak effect of changes in the content of rock-forming minerals and a significant effect of different types of fractures on the value of elastic and acoustic anisotropy (10-40%) was proved. Elastic constants of models with layered and chaotic orientation of structural-textural elements are calculated. It is established that most models, as well as basic samples have a rhombic type of acoustic symmetry. When comparing the stereoprojections of the anisotropy parameters of real samples with the stereoprojections obtained during modeling, the authors found that in most samples there is a double system of cracking: chaotic and directed in the area of shale. The results of mathematical modeling showed that for models with ordered crack orientation, the change in the format and concentration of voids is a defining characteristic. This effect is significantly smaller for models with a chaotic arrangement of structural elements. It is proved that models with a combined (layered and chaotically oriented) type of fracture are the closest to real samples. The authors show that this technique allows you to create and operate models close to the real geological environment.

Evolution of Chemical Composition and Modeling of Growth Nonmetallic Inclusions in Steel Containing Yttrium.

The programs WYK_Stal and Bi-Growth, developed at AGH-UST, Kraków, Poland, were used for simulating the refining process, the formation of non-metallic inclusions, and their growth. The Fe-Y-Al-O-S-Ca system in pre-oxidized steel was analyzed, where yttrium formed precipitates from both O and S. When first Al and second Y were added to steel, the proportion of Al2O3 inclusions remained constant. This resulted in higher yttrium losses for oxide formation, whereas the sulfur content promoted sulfide phase formation. The introduction of yttrium at the end of refining contributed to reducing the consumption of this element in the non-metallic phase formation. The addition of aluminum and then calcium were sufficient to achieve a high degree of deoxidation and desulfurization. Calculations performed with WYK_Stal for both (a) and (c) versions of the model showed that the sulfide phase was constituted by CaS and FeS (model c) and CaS (model (a)). The participation of the calcium sulfide phase turned out to be dominant in the inclusions. Their presence was also identified in the slag phase. Simulations of the growth of complex oxide and oxo-sulfide inclusions using the Bi_Growth program showed that the yttrium content of the steel has a decisive role in the formation of complex oxide inclusions and the final oxygen content of the steel. In contrast, for the growth of oxide-sulfide inclusions, the character of growth is determined by the sulfur content of steel.

Mineralogy, Fluid Inclusions, and Isotopic Study of the Kargah Cu-Pb Polymetallic Vein-Type Deposit, Kohistan Island Arc, Northern Pakistan: Implication for Ore Genesis

The Kargah Cu-Pb polymetallic deposit is a newly discovered ore deposit from the Gilgit-Baltistan region, located in the Kohistan Island Arc, northern Pakistan. However, this area is poorly researched on the ore genesis, and its origin and the evolution of its magmatic-hydrothermal system remain unclear. Three stages of mineralization were identified, including quartz-pyrite, quartz-sulfide, and carbonate representing early, middle, and late stages, respectively. The major ore minerals are pyrite, chalcopyrite, galena, and zincian tetrahedrite with minor native silver, and native gold mainly distributed in pyrite. Here, we present a systematic study on ore geology, hydrothermal alterations, trace element composition of pyrite, fluid inclusions, and isotopes (S and Pb) characteristics to gain insights into the nature of the ore-forming fluids, types of unknown deposits, and hydrothermal fluid evolution. The high Co/Ni ratio (1.3–16.4) and Co content (average 1201 ppm), the low Mo/Ni ratio (0.43–0.94) and Mo contents (average 108 ppm) of both Py-I and Py-II suggest a mafic source for the mineralization. The Au-Ni plots, Co-As-Ni correlation, and the δ34S values range from −2.8 to 6.4‰ (average of 3.4‰) indicating the affiliation of the mineralization with a mantle-derived magmatic-hydrothermal provenance. The Pb isotope data showing the narrow variations in 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values suggest a single lead source from crustal-derived materials. The microthermometry data suggest that the dominant mechanisms are fluid boiling and mixing for mineral precipitation at temperatures ranging between 155 and 555 °C, and represent an intrusion-related magmatic-hydrothermal environment for the Kargah Cu-Pb polymetallic deposit.

Nuclear and cytoplasmic huntingtin inclusions exhibit distinct biochemical composition, interactome and ultrastructural properties

Despite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington’s disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt cytoplasmic and nuclear inclusions in mammalian cells and primary neurons overexpressing mutant exon1 of the Htt protein. Our findings provide unique insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve the polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; the recruitment and accumulation of remodeled or dysfunctional membranous organelles, and the impairment of the protein quality control and degradation machinery. We also show that nuclear and cytoplasmic Htt inclusions exhibit distinct biochemical compositions and ultrastructural properties, suggesting different mechanisms of aggregation and toxicity.

Fluorite Mineralization Related to Carbonatitic Magmatism in the Western Transbaikalia: Insights from Fluid Inclusions and Trace Element Composition

Fluorite mineralization associated with different types of magmatism is common in the Western Transbaikalia. This study deals with Arshan, Yuzhnoe, and Ulan-Ude fluorite occurrences, which are the most significant examples of carbonatite-related fluorite mineralization in the region. The present paper focused on new fluorite geochemistry and fluid inclusion data, is aimed at revealing conditions of the fluorite mineralization formation, highlighting its genetic relationship with magmatism, compared to other deposits of this type. All the three locations belong to the Late Mesozoic Central Asian carbonatite province. Fluorites here are characterized by high rare earth elements (REE), Sr, and elevated La/Yb values. Fluid inclusions data imply that the formation of fluorite mineralization is a long process extending from late magmatic to the hydrothermal stage. Early fluorite crystallized from sulfate-carbonate orthomagmatic fluids at temperatures up to 500 °C. True hydrothermal fluorite was formed from the same fluids that were probably mixed with meteoric waters, which caused the temperature to drop to below 420 °C and led to an increase in the chloride component. The REE compositions of fluorite from the studied locations are similar to compositions of REE-rich fluorites from carbonatite-related deposits around the world.

Influence of Inclusions on the Nucleation of Acicular Ferrites in a Ti–Zr‐Bearing Steel

Laboratory experiments are conducted to study the influence of inclusions on the nucleation of acicular ferrite in Ti–Zr‐bearing steels. The ferrite transformation in steels with different Ti–Zr contents is observed using a high‐temperature confocal laser scanning microscope (HT‐CLSM). The average composition and size of inclusions and the information about the nucleation of acicular ferrite (AF) are analyzed using a scanning electron microscope. When the content of titanium in the steel increased from 70 to 370 ppm, the main composition in the inclusion transformed from Al2O3 to Ti2O3, the volume fraction of AF increased from 24.4% to 52.5%. The average content of ZrO2 in inclusions is 0%, 18.51%, and 90.39%, when the Zr content of steel is 0 80, and 140 ppm, the volume fraction of AF is 52.5%, 76.9%, and 56.8%. The relationship between the cosine of the contact angle at the inclusions‐ferrite interface and the diameter of inclusions is established based on experimental results, which is consistent with the results calculated based on the classic nucleation theory.

A dry lunar mantle reservoir for young mare basalts of Chang\u2019e-5

The distribution of water in the Moon’s interior carries implications for the origin of the Moon1, the crystallization of the lunar magma ocean2 and the duration of lunar volcanism2. The Chang’e-5 mission returned some of the youngest mare basalt samples reported so far, dated at 2.0 billion years ago (Ga)3, from the northwestern Procellarum KREEP Terrane, providing a probe into the spatiotemporal evolution of lunar water. Here we report the water abundances and hydrogen isotope compositions of apatite and ilmenite-hosted melt inclusions from the Chang’e-5 basalts. We derive a maximum water abundance of 283 ± 22 μg g−1 and a deuterium/hydrogen ratio of (1.06 ± 0.25) × 10–4 for the parent magma. Accounting for low-degree partial melting of the depleted mantle followed by extensive magma fractional crystallization4, we estimate a maximum mantle water abundance of 1–5 μg g−1, suggesting that the Moon’s youngest volcanism was not driven by abundant water in its mantle source. Such a modest water content for the Chang’e-5 basalt mantle source region is at the low end of the range estimated from mare basalts that erupted from around 4.0 Ga to 2.8 Ga (refs. 5,6), suggesting that the mantle source of the Chang’e-5 basalts had become dehydrated by 2.0 Ga through previous melt extraction from the Procellarum KREEP Terrane mantle during prolonged volcanic activity.

Effect of Ti content on the inclusions, microstructure and fracture mechanism of X100 pipeline steel laser-MAG hybrid welds

Laser-MAG hybrid welding has a wide range of application prospects for pipeline steel welding, because it combines the advantages of arc welding and laser welding. However, the brittle microstructure of bainite or martensite in hybrid welding results in low impact toughness, and thus it cannot be used in pipeline laying. Hence, in this study, we induced acicular ferrite (AF) into laser-MAG hybrid welds, because of its good impact toughness. We prepared X100 steel welds with different Ti content using laser-MAG hybrid welding. Then, the microstructure evolution, impact toughness and fracture mechanism of the welds with different Ti content were investigated. The results illustrated that with increasing Ti content, the outer layer inclusion composition evolved from mostly Al2O3 to Ti2O3 and finally to TiC. Thus, Ti2O3 induced AF nucleation by forming an Mn-depleted zone, which caused the volume fraction of AF to initially increase and then decrease. The impact toughness also changed accordingly (16.3 → 21.9→8.7J) and the cracks nucleated and propagated in granular bainite during impact fracture. When they encountered AF, the cracks deflected and even stopped propagating. Therefore, by controlling the Ti content in the laser-MAG hybrid weld, the impact energy at −40 °C was higher than in the base metal. In addition, the higher quantity of AF with a high effective grain boundary density (0.57/μm) and low kernel average misorientation value could effectively hinder crack propagation and consequently improve impact toughness.

Evolution of oxide and nitride inclusions during processing of stainless steel

Because of its superior properties, stainless steel has been widely used for many applications. Nonmetallic inclusions can influence the quality of stainless steel products. A set of samples was used to track the response of inclusion composition during processing of a heat of titanium-bearing 18% chromium steel, from deoxidation after decarburization, to the solidified slab. The oxide inclusions responded as expected to additions of deoxidizers and calcium treatment, changing from silica to alumina and spinels, and then to calcium aluminates. The samples confirmed that titanium nitride can nucleate on liquid calcium aluminate during steel solidification.

Evolution of the Non-metallic Inclusions Influenced by Slag-Metal Reactions in Ti-Containing Ferritic Stainless Steel

Laboratory experiment and thermodynamic calculation for the Ti-containing 24 mass pct Cr ferritic stainless steel with a CaO-SiO2-Al2O3-MgO system slag were performed to investigate the effect of slag addition on the inclusion characteristics in molten steel. The morphology, composition, and size evolution of inclusions in steel samples were analyzed in three-dimensional by the electrolytic extraction method and in two-dimensional by the automatic analysis method. The results showed that the Ti content significantly decreased after the slag addition. However, the change of the Si content showed an opposite tendency. The decrease of the Ti content in steel was due to the reduction of SiO2 and Al2O3 in the slag by dissolved Ti in steel. An increase of the TiO2 content in the slag can decrease the Ti loss in steel based on the slag-steel kinetic analysis. The total O content in the steel melt decreased from 62 to 26 ppm, and the steel cleanliness was improved, since the number density of inclusions decreased after the slag refining. The results of a kinetic analysis showed that the rate-determining step of the oxidation of Ti in the steel and the reduction of SiO2 in the slag were the mass transfer on the slag side. In addition, high Ti2O3-containing inclusions were found to be transformed to Cr2O3-Ti2O3-Al2O3 and Cr2O3-Ti2O3-SiO2 system inclusions after the slag addition. The Al2O3 contents in inclusions increased while the Ti2O3 contents decreased with time. However, there were some amount of high melting point inclusions with high Al2O3 content, which were not what we expected. When plotted on logarcxithmic scales, the mole ratio X_{{{text{Al}}_{2} {text{O}}_{3} }} /(X_{{{text{Ti}}_2 {text{O}}_{3} }} cdot X_{{{text{Cr}}_{2} {text{O}}_{3} }} ) values of the inclusions were expressed as a linear function of the a_{text{Al}}^{2} /(a_{Ti}^{2} cdot a_{text{Cr}}^{2} cdot a_{text{O}}^{3} ) values of the steel melts with a slope of unity, which was theoretically expected.

Periodic homogenization and damage evolution in RVE composite material with inclusion

This work deals with the coupling between a periodic homogenization procedure and a damage process occurring in a RVE of inclusion composite materials. We mainly seek on the one hand to determine the effective mechanical properties according to the different volume fractions and forms of inclusions for a composite with inclusions at the macroscopic level, and on the other hand to explore the rupture mechanisms that can take place at the microstructure level. To do this; the first step is to propose a periodic homogenization procedure to predict the homogenized mechanical characteristics of an inclusion composite. This homogenization procedure is applied to the theory based on finite element analysis by the Abaqus calculation code. The inclusions are modeled by a random object modeler, and the periodic homogenization method is implemented by python scripts. It is then a matter of introducing the damage into the problem of homogenization, that is to say; once the homogenized characteristics are assessed in the absence of the damage initiated by microcracks and micro cavitations, it is then possible to introduce damage models by a subroutine (Umat) in the Abaqus calculation code. The verifications carried out focused on RVE of composite materials with inclusions.

Optimizing Slag Content to Control Ds-Type Inclusions in 10B21 Cold Heading Steel

Ds-type inclusions during production are an important factor affecting the performance and quality of manufactured 10B21 steel. To minimize Ds-type inclusions in steel and improve the production qualification rate of steelmaking plants, a refining slag system optimization scheme was proposed based on the analysis of current inclusion evolution during the steelmaking process, and industrial tests were conducted to verify improvements resulting from application of the proposed scheme. The results showed that the composition of Ds inclusions in 10B21 steel are mainly CaO–Al2O3–MgO–CaS–TiN, which exists in the form of calcium–magnesium aluminate coated with titanium nitride and calcium sulfide. The main reason for the formation of Ds inclusions is the poor fluidity of the refining slag and its low capability to absorb inclusions. The poor coverage of the refining slag on the molten steel during refining can easily cause secondary oxidation of the molten steel. Thus, the formation and growth of Ds-type inclusions are aggravated after the calcium feeding line and soft blowing operation. Here, we propose to minimize Ds inclusions using our optimized refined slag system. The mass percentage of the optimized slag system is CaO: 55–60%, Al2O3: 20–35%, SiO2: 3–7%, MgO: 4–8%, (MnO + FeO) < 1%, and the basicity is controlled within the range of 7–11. We observed that our optimized refining slag system has a significantly improved ability to remove inclusions, particularly Ds inclusions, which improves the qualification rate of 10B21 steel.

Ore-Forming Fluid Evolution of Shallow Polyhalite Deposits in the Kunteyi Playa in the North Qaidam Basin

Polyhalite occurrence in the Kunteyi Playa in the Qaidam Basin has been known for many years. However, the genetic mechanism of this deposit remains unclear. In this study, a typical section in the playa depocenter is selected to study the polyhalite mineralogy combined with the homogenization temperature and composition of halite fluid inclusions in shallow evaporitic strata. The results show that 1) the main evaporite minerals in the strata are halite and polyhalite; no common gypsum is found; 2) analyses of homogenization temperatures of halite fluid inclusions indicate that a higher temperature is needed for polyhalite generation compared with other saline minerals; and 3) the fluid inclusion chemical analysis shows that they are sulfate-type minerals with a shortage of Ca. Thus, it can be concluded that the formation of polyhalite is not related to gypsum replacement, and deep oilfield brines may provide a Ca source and a higher temperature for polyhalite formation, where the mixing and interaction occurred between K- and Mg-enriched sulfate brines and deep Ca-enriched brines under the control of climate and tectonics in the study area. While most polyhalite was generated natively, some formed during secondary generation, which was potentially related to replacement with carnallites or sylvites.

Oxygen fugacity during tin ore deposition from primary fluid inclusions in cassiterite

Reconstruction of the redox conditions during formation of rocks and ore deposits often remains a challenging task, particularly if no reactions buffering the oxygen fugacity ƒO2 can be identified. This information is crucial for genetic models of numerous ore deposit types, and consequently there has been long-standing and in recent years increasing research activity addressing complexation and redox state of metals in fluids at high temperatures. In this study, we constrain ƒO2 during tin ore formation from the composition of primary fluid inclusions in the principal ore mineral cassiterite, SnO2. We show that the analysed cassiterite samples from worldwide locations (from hydrothermal veins, greisens, skarn deposits, and pegmatites) precipitated at ƒO2 between QFM (quartz-fayalite-magnetite) and above NNO (nickel-nickel oxide), with more oxidizing conditions up to MH (magnetite-hematite) for certain vein/greisen deposits. This, together with in situ Raman spectroscopic experiments, supports the hypothesis that Sn(IV) prevailed over Sn(II) in many if not most tin-ore forming hydrothermal fluids, which implies that redox reactions play a smaller role than assumed in previous formation models of hydrothermal tin deposits.

Inclusion Characteristic of Blue Sapphire from Australia

The main purpose of this study is to observe the abundant inclusions of blue sapphire samples from Australia and analyze the composition of inclusions and provide a theoretical basis for the identification of its origin.The Leica M205A microscopic camera was used to finish the image acquisition of characteristic inclusions in blue sapphires from Australia. Laser Raman spectrometer was used to test inclusion composition.The result showed that the sapphire samples generally had obvious uneven colour distributions, healing fissures and partings. Some samples have hexagonal ribbons. Microscopic observation showed solid phase inclusions, tubular gas-liquid inclusions, fingerprint inclusions, and occasionally three-phase inclusions.Specially, some inclusions occur in the form of bicrystals.The inclusions identified by Raman spectroscopy include zircon, rutile, anatase, hematite, niobite, nepheline and CO2.