scholarly journals Variety of Iron Oxide Inclusions in Sapphire from Southern Vietnam: Indication of Environmental Change during Crystallization

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 241
Author(s):  
Doan Thi Anh Vu ◽  
Alongkot Fanka ◽  
Abhisit Salam ◽  
Chakkaphan Sutthirat
Keyword(s):  
Iron Oxide ◽  
Environmental Change ◽  
Electron Probe ◽  
Mineral Chemistry ◽  
Cooling Process ◽  
Alluvial Deposits ◽  
Oxide Inclusions ◽  
Electron Probe Micro Analyzer ◽  
Southern Vietnam ◽  
Mineral Inclusions

Sapphires from alluvial deposits associated with Cenozoic basalts in Southern Vietnam were collected for investigation of mineral inclusions. In this report, primary iron oxide inclusions were focused on, with detailed mineral chemistry using a Raman spectroscope and electron probe micro-analyzer. Consequently, a variety of iron oxide inclusions were recognized as wüstite, hercynite, and ilmenite. Ilmenite falling within an ilmenite–hematite series ranged in composition between Il24-30He36-38Mt35-40 and Il49-54He34-40Mt7-10, classified as titanomagnetite and titanohematite, respectively. Wüstite with non-stoichiometry, (Fe2+0.3-0.9)(Ti3+<0.179Al3+≤0.6Cr3+<0.1Fe3+≤0.46)☐≤0.23O, was associated with hercynite inclusions, clearly indicating cogenetic sapphire formation. Wüstite and sapphire appear to have been formed from the breakdown reaction of hercynite (hercynite = sapphire+wüstite) within a reduction magma chamber. Titanohematite and titanomagnetite series might have crystallized during iron–titanium reequilibration via subsolidus exsolution under a slightly oxidized cooling process.

IRON OXIDE INCLUSIONS IN THE RAINBOW LATTICE SUNSTONE FROM AUSTRALIA

2020 ◽  
Author(s):  
Shiyun Jin ◽  
◽  
Ziyin Sun ◽  
Karen V. Smit ◽  
Aaron C. Palke
Keyword(s):  
Iron Oxide ◽  
Oxide Inclusions

scholarly journals Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 619 ◽  
Author(s):  
Xiang Li ◽  
Xiao Long ◽  
Linzhu Wang ◽  
Shouhao Tong ◽  
Xiutao Wang ◽  
...  
Keyword(s):  
Outer Layer ◽  
Three Dimensional ◽  
Average Diameter ◽  
Inclusion Size ◽  
Number Density ◽  
Cooling Process ◽  
Oxide Inclusions ◽  
Industrial Experiments ◽  
Size Number

In order to study the effect of Ca and sulfur contents on the characteristics of inclusions, industrial experiments using 95CrMo steel were conducted. SEM-EDS detections and stereological analysis were used to probe the characteristics of inclusions, including their compositions, morphologies, size, number density, and distribution. The results indicate that there were mainly three types of inclusions in 95CrMo steel billets with 6–18 ppm Ca and 30–100 ppm S: inclusions with single-phased morphology mainly composed of oxides; isolated MnS/CaS-only inclusions; inclusions with multi-phased morphology. The three-dimensional inclusion size distribution suggests that there were more Type-1 inclusions with a small size in low S containing steels. The average diameter of all types of inclusions increased with increasing Ca or S content in 95CrMo steel, indicating that the formation of MnS and CaS coarsened their size. The density distribution of inclusions indicates that the more inclusions there are, the more easily they aggregate and collide. Moreover, it is presumably concluded that the formation of sulfide in the outer layer of oxide inclusions weaken the attraction between oxide inclusions. The equilibrated transformation and formation of inclusions during the cooling process of 95CrMo steel was discussed based on thermodynamic calculation. The equilibrated transformation trajectory of inclusions in 95CrMo steel during the cooling process was Ca2SiO4 + MgO → Ca3MgSi2O8 → Spinel + CaS, which was corresponding to the detected results. The precipitation regular of sulfide was obtained. The formation mechanism for three types of inclusions was discussed.

Microstructure Characteristics of the Black-Glazed Shreds Excavated from the Qingliangsi Kiln

2011 ◽  
Vol 492 ◽  
pp. 112-117 ◽  
Author(s):  
Zi Wei Liu ◽  
Zhi Gang Zhang ◽  
Hua Li ◽  
Wei Wu ◽  
Jia Jie Hua ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Iron Oxide ◽  
Field Emission ◽  
Electron Probe ◽  
Zone Axis ◽  
Microstructure Characteristics ◽  
Transmission Electron ◽  
Oxide Crystal ◽  
Crystal Phases ◽  
Micro Structures

The black-glazed shreds from Qingliangsi kiln were studied. The glaze and body micro- structures, compositions and crystal phases were observed and analyzed by field emission scanning electron, microscope multiple functions electron probe-energy spectrum instrument and field emission transmission electron microscope. The iron oxide crystal in oil spot was mainly the ε-Fe2O3 in the orientation of the zone axis [001], and also few content of ε-Fe2O3 in the orientation of the zone axis [412]. The brown oil spots on the glaze surface were aggregations of a great deal of iron oxide hematite crystals. Bodies of black-glazed shreds have high Al2O3(26.47 % ~ 30.48%) and low SiO2 (62.77% ~ 66.20%), which pertained to the typical recipe of north porcelain bodies. The glaze are attributed to calcium-alkali glaze, and according to the ratio of Al2O3:SiO2, it belongs to the crystallization glaze.

Preparation of Al2O3/Al-Si Composites by In Situ Reaction of Fe2O3+MnO2/Al System

2015 ◽  
Vol 816 ◽  
pp. 48-53
Author(s):  
Jing Zhang ◽  
Hua Shun Yu ◽  
Xin Ting Shuai ◽  
Hong Mei Chen ◽  
Guang Hui Min
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Electron Probe ◽  
Room Temperature ◽  
Manganese Content ◽  
Hardness Test ◽  
Test Results ◽  
Electron Probe Micro Analyzer ◽  
Transmission Electron ◽  
Polygonal Shape

Al2O3 particles reinforced ZL109 composites were prepared by in-situ reaction between Fe2O3+MnO2 and Al in this paper. The influence of ratio of Mn to Fe on the morphologies of Al-Si-Mn-Fe phase and mechanical properties of the composites was investigated. The microstructure was studied by electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM). The results show that the Al2O3 particles displaced by the Fe2O3+MnO2/Al system are in nanosize. The acicular Al-Si-Fe phases change from acicular to polygonal shape and become smaller with the increase manganese content. The hardness test results have no big difference on the composites. However, the ultimate tensile strength at room temperature and 350°C enhance evidently with the increasing of Mn/Fe.

scholarly journals Studies on Structure and Coloring of Aluminum Anodic Oxide Films by Electron Probe Micro-Analyzer

1972 ◽  
Vol 23 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Toshiro TAKAHASHI ◽  
Toshihiro NAGANO ◽  
Kenji WADA ◽  
Masashi IKEGAYA ◽  
Hideo TAGAI
Keyword(s):  
Electron Probe ◽  
Oxide Films ◽  
Anodic Oxide ◽  
Anodic Oxide Films ◽  
Electron Probe Micro Analyzer

Almandine garnet phenocrysts in a ~1 Ga rhyolitic tuff from central India

2008 ◽  
Vol 146 (1) ◽  
pp. 133-143 ◽  
Author(s):  
SARBANI PATRANABIS-DEB ◽  
JUERGEN SCHIEBER ◽  
ABHIJIT BASU
Keyword(s):  
Central India ◽  
Mineral Chemistry ◽  
Triple Junctions ◽  
Fine Grained ◽  
Mineral Inclusions ◽  
Major Oxide ◽  
Shale Formation ◽  
Igneous Zircon ◽  
Compositional Variability ◽  
Lower Crustal

AbstractWe report on the newly discovered almandine garnet phenocrysts in rhyolitic ignimbrites (Sukhda Tuff) in the Precambrian Churtela Shale Formation of the Chhattisgarh Supergroup in central India. SHRIMP ages of igneous zircon from the ignimbrites range from 990 Ma to 1020 Ma. These ignimbrites exhibit characteristic eutaxitic texture with compacted curvilinear glass shards with triple junctions. Quartz (commonly embayed; bluish cathodoluminescence) and albite (altered but retaining ghosts of twinning) are common phenocrysts; others are apatite, ilmenite, rutile, magnetite, zircon, monazite and garnet. There are no metamorphic or granitic xenoliths in the ignimbrites. Garnet grains occur as isolated broken isotropic crystals with sharp or corroded boundaries in a very fine-grained groundmass of volcanic ash that consists principally of albite, quartz, magnetite and glass. They do not have any systematically distributed inclusions. A few have penetratively intergrown phenocrysts of apatite, ilmenite, rutile and zircon, which we interpret as subophitic texture. Extensive SEM-BSE imaging of more than 100 grains and electron microprobe traverses across about 30 grains showed no zoning or systematic compositional variability. Common (metamorphic) garnets are usually zoned with respect to Fe–Mg–Mn and typically have mineral inclusions. We infer, therefore, that these observed garnets are not metamorphic xenocrysts. The average major oxide composition of analysed garnets from five different horizons within the Sukhda Tuff, spanning approximately 300 m of the stratigraphic section, have very small standard deviation for each element, which is suggestive of a single magmatic source. Phenocrysts of quartz, including those in contact with coexisting garnets, show blue scanning electron CL, indicating rapid cooling from high temperature; this suggests that adjacent coexisting garnets are not slowly cooled restites. We conclude, on the basis of texture, mineral chemistry and absence of any indicative xenoliths or xenocrysts, that these almandine garnets (Al78.7Py12.3Gr7.4Sp1.6) are phenocrysts within the Sukhda Tuff. Almandine of such composition is stable under high pressure. We infer that almandine crystallized at lower crustal depths in a magma that ascended very rapidly and may have erupted explosively.

scholarly journals Geochemical and Mineralogical Characteristics of Garnierite From the Morowali Ni-Laterite Deposit in Sulawesi, Indonesia

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuri Choi ◽  
Insung Lee ◽  
Inkyeong Moon
Keyword(s):  
Cation Exchange ◽  
Electron Probe ◽  
Mineralization Process ◽  
Ore Deposit ◽  
Electron Probe Micro Analyzer ◽  
Mineralogical Characteristics ◽  
Fe Content ◽  
Geochemical Study ◽  
Different Types ◽  
Bottom To Top

The Morowali Ni-laterite deposit is located in the East Sulawesi Ophiolite, which is a large ophiolite belt on Sulawesi Island, Indonesia. The Morowali deposit is developed on a laterite profile due to ophiolite weathering, with saprolite, limonite, and ferruginous cap horizons from the bottom to top. Based on the occurrence of garnierite as the main ore, occurring in the saprolite horizon, it can be classified that the ore deposit is hydrous Mg silicate-type. The Ni ore is classified into different types based on color and XRD and electron probe micro-analyzer analyses. Whole-rock geochemical study was also conducted to understand the mineralization process. The Morowali Ni deposit consists of serpentine-like and talc-like phases. The serpentine-like phase consists of Ni-lizardite and karpinskite (0.76–38.26 wt% NiO) while the talc-like phase is mainly composed of kerolite (4.02–8.02 wt% NiO). The serpentine-like garnierite exhibits high Ni and Fe contents and occurrence similar to that of the serpentine observed in the saprolite horizon, suggesting the serpentine-like garnierite originated from the bedrock, and Mg-Ni cation exchange occurred during laterization. Contrastingly, the lower Fe content of the talc-like phase (0.01–0.05 wt%) than the serpentine-like phase (0.14–7.03 wt%) indicates that the talc-like garnierite is of secondary origin since Fe is immobile during weathering. The Morowali Ni-laterite deposit was mainly formed during laterization. The repetition of dry and wet cycles in each year results in the formation of secondary garnierite.

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