scholarly journals Contribution to the chemical composition of minerals of the mimetite-pyromorphite series from the Guatomo mine near Tham Thalu, Bannang Sata District, Yala Province (Thailand)

2020 ◽  
Vol 28 (2) ◽  
pp. 237-245
Author(s):  
Martin Števko ◽  
Jiří Sejkora ◽  
Zdeněk Dolníček
Keyword(s):  
Chemical Composition ◽  
Composition Of Minerals ◽  
Host Rocks ◽  
Compositional Series

The Guatomo mine is considered as one of the classic localities of mimetite worldwide. The chemical composition of six samples of minerals of mimetite-pyromorphite series from the Guatomo mine, representing different morphologies, colours as well as various geological environments/host rocks, was studied in detail by EMPA-WDS. This study revealed that both mimetite as well as pyromorphite are present at the Guatomo mine, representing rather variable compositional series ranging from the nearly end member mimetite (sample M1 - up to 0.03 apfu of P, sample M4 - up to 0.23 apfu of P and sample M5 with up to 0.18 apfu of P), through P-enriched mimetite (with 0.38 apfu of P) and As-rich pyromorphite (with 0.82 apfu of As, sample M2) up to As-enriched pyromorphite (sample M3 with As content reaching up to 1.03 apfu and sample M6 with up to 0.80 apfu of As). Besides of Pb, As, P and Cl only negligible amounts of Ca, V and S were detected in studied samples.

scholarly journals MINERAL CHEMISTRY AND GEOCHEMISTRY OF HYPERSTHENE-BEARING DIORITE FROM ERUSU AKOKO, SOUTHWESTERN NIGERIA

2020 ◽  
Vol 4 (1) ◽  
pp. 13-18
Author(s):  
E. J. Oziegbe ◽  
V. O. Olarewaju ◽  
O. O. Ocan
Keyword(s):  
Chemical Composition ◽  
Chemical Properties ◽  
Mineral Chemistry ◽  
Accessory Mineral ◽  
Southwestern Nigeria ◽  
Hydrous Minerals ◽  
Icp Ms ◽  
Composition Of Minerals ◽  
Textural Relationship ◽  
Opaque Minerals

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.

scholarly journals Preparation of Thin Sections

1998 ◽  
Vol 6 (7) ◽  
pp. 8-9
Author(s):  
Ian Chaplin
Keyword(s):  
Chemical Composition ◽  
Thin Section ◽  
Microprobe Analysis ◽  
Rock Sample ◽  
Rock Type ◽  
X Rays ◽  
Thin Sections ◽  
Economical Method ◽  
Optical Examination ◽  
Composition Of Minerals

The optical examination of a rock sample in thin section is the quickest and most economical method for classifying rock type and determining which analytical route to follow.Thin sections for transmitted light are the most common, but there are also:Polished Thin Sections • Polished sections are used for classification and identification of minerals that cannot be determined in standard thin sections. They are also essential for microprobe analysis. Minute mineral grains are analyzed by bombarding them with a focused bean of electrons, which generate x-rays, characteristic of the elements within the grains. X-rays are identified and quantified to determine the chemical composition of minerals.

scholarly journals Chemical equilibrium of groundwater with minerals of the host rocks in Upper Jurassic sediments (Arctic regions of Western Siberia)

2019 ◽  
Vol 98 ◽  
pp. 01037 ◽  
Author(s):  
Dmitry A. Novikov
Keyword(s):  
Chemical Composition ◽  
Chemical Equilibrium ◽  
Western Siberia ◽  
Upper Jurassic ◽  
The Arctic ◽  
Geochemical Environment ◽  
Rock System ◽  
Arctic Regions ◽  
Host Rocks ◽  
Mineral Changes

The results of thermodynamic calculations for a water-rock system in the Upper Jurassic deposits of the Arctic regions of Western Siberia are presented. In the area under investigation the groundwaters have been identified with mineralization up to 63.3 g/L and various chemical composition and genesis. Despite the long interaction with the rock (150-160 ma) equilibrium with endogenous minerals (albite, microcline and anorthite) is practically not observed. At the same time, groundwaters are in equilibrium with clay minerals and micas, such as: Caand Na-montmorillonites, kaolinite, paragonite, margarite, illite, muscovite and Mg-chlorite. The establishment of a balance of groundwater with primary aluminosilicate minerals is also affected by interactions with carbonate minerals. The differences in composition of groundwater in equilibrium with certain aluminosilicates and carbonates indicate that the mineral changes are formed from a solution of a strictly defined chemical composition in an appropriate geochemical environment.

scholarly journals Rhenium - rich molybdenites in Thracian porphyry Mo±Cu occurrences, NE - Greece

2001 ◽  
Vol 34 (3) ◽  
pp. 1015 ◽  
Author(s):  
Β. ΜΕΛΦΟΣ ◽  
Π. ΒΟΥΔΟΥΡΗΣ ◽  
Κ. ΑΡΙΚΑΣ ◽  
Μ. ΒΑΒΕΛΙΔΗΣ
Keyword(s):  
Chemical Composition ◽  
Hydrothermal Alteration ◽  
Fluid Inclusions ◽  
Mineral Chemistry ◽  
Rare Element ◽  
Alteration Zones ◽  
Porphyry Cu ◽  
Mineral Assemblages ◽  
Host Rocks

The present study correlates both the mineralogy of the hydrothermal alteration and the mineral chemistry of molybdenites from three porphyry Mo ± Cu occurrences in Thrace: Melitena, Pagoni Rachi/Kirki and Ktismata/ Maronia. The mineralisations are genetically related to calcalkaline, subvolcanic bodies of Tertiary age. According to their mineralogical and chemical composition the host rocks are characterized as dacite (Melitena), dacitic andésite (Pagoni Rachi) and porphyry microgranite (Ktismata/Maronia). The molybdenites occur in disseminated form, as fracture fillings, as well within quartz stockworks crosscuting the central alteration zones of the intrusives. They are accompanied by the following mineral assemblages: quartz, sericite, pyrophyllite, diaspore, Ca-Ba-rich alunite, pyrite (Melitena); quartz, albite/K-feldspar, biotite, actinolite, magnetite (Pagoni Rachi); and sericite, kaolinite, pyrophyllite, chlorite (Ktismata). Preliminary microthermometric results showed homogenisation temperatures from 352° to 390 °C for Pagoni Rachi area and from 295° to 363 °C for Melitena area. The salinities range between 4.5 and 6.1 wt% eq. NaCl and between 2.7 and 3.4 wt% eq. NaCl, respectively. Detailed study on over 400 fluid inclusions from the porphyry Cu-Mo deposit in Maronia area revealed formation temperatures from 300° to 420 °C, whereas salinities are distincted in two different groups from 6 to 16 wt% eq. NaCl and from 28 to 55 wt% eq. NaCl. The chemical composition of the molybdenites from the three porphyry Mo±Cu deposits in Thrace was studied with 155 microprobe analyses. The results revealed unusual high and variable Re concentrations in the studied molybdenites. Re content in molybdenite from Melitena area vary from 0.21 to 1.74 wt%, 0.79 wt% on average. The highest values were measured in samples from Pagoni Rachi (0.45-4.21 wt%, 1.98 wt% on average). Finally, microprobe analyses from molybdenite in Ktismata/Maronia showed Re content between 0.12 and 2.88 wt% (0.76 wt% on average). Rhenium is a very rare element with many definite uses, and is mainly associated with molybdenite in porphyry type deposits. According to the data published so far the Re content in molybdenite reaches up to 0.42 wt%. It is obvious therefore that such high Re concentrations (0.12 to 4.22 wt%) from the studied molybdenites in Thrace, are very ineresting for a possible future exploitation.

scholarly journals Less-common and rare earth elements of the Pechenga region ores

2021 ◽  
Vol 11 (3) ◽  
pp. 406-421
Author(s):  
K.V. Lobanov ◽  
◽  
A.V. Grigoryeva ◽  
A.V. Volkov ◽  
M.V. Chicherov ◽  
...  
Keyword(s):  
Trace Elements ◽  
Rare Earth ◽  
Chemical Composition ◽  
Rare Earth Elements ◽  
The Arctic ◽  
High Tech ◽  
Wide Range ◽  
Ore Minerals ◽  
High Enrichment ◽  
Host Rocks

The article presents the investigations in the Pechenga ore region — one of the largest industrial regions in the Arctic zone of Russia, located on the territory of the Murmansk area. The researchers obtained new data on the chemical composition of the main ore minerals, the content of trace elements, including rare earths (REE), in the ores of the Pilguyarvi and Vostok deposits and late polymetallic veins of the Pechenga region. They found that the main textural types of ores (massive, veined and disseminated) differ significantly in chemical composition and content of rock and ore-forming components. They also revealed the enrichment of ores with a wide range of trace elements. In comparison with the upper crust, the Pechenga ores are clearly enriched with chalcophilic and siderophilic trace elements. The enrichment coefficients of ore elements reach mainly tens (Cr, Au, Cd) hundreds (Ag, Se, Re, Pt) and thousands (Ni, Cu, Ir) times. The distribution of trace elements in various types of Cu-Ni ores has a great similarity, which indicates their geochemical affinity and synchronous participation in ore formation. The geochemical features are in good agreement with the mineral composition of the ores. The concentration of rare earth elements in the main types of ores, with the exception of massive ores and late polymetallic veins, exceeds the level of the chondrite standard and the REE fractionation is weak. The composition of the REE in ores came by from the host rocks. The research has established the high enrichment of all types of Re, Bi and Cd ores, which are potentially industrially significant as high-tech metals and are of considerable interest for associated mining.

scholarly journals Leading genetic types of base metal deposits of Rudny Altai

2021 ◽  
pp. 11-16
Author(s):  
M.A Mizernaya ◽  
B.A Dyachkov ◽  
A.P Pyatkova ◽  
A.P Miroshnikova ◽  
Z.I Chernenko
Keyword(s):  
Spectral Analysis ◽  
Chemical Composition ◽  
Field Studies ◽  
Sulfide Mineralization ◽  
Laboratory Studies ◽  
Spatial Confinement ◽  
Genetic Types ◽  
Modern Methods ◽  
Polymetallic Mineralization ◽  
Host Rocks

Purpose. Study on the processes contributing to the formation of pyrite-polymetallic mineralization in the Rudny Altai, development of recommendations for directions for further research. Methodology. Analysis of literature and fund materials, field studies within known ore fields and deposits, sampling and laboratory studies: spectral analysis, studies on the chemical composition of host rocks (ISP-MS Agilent 7500cx), study on the mineral composition of the main types of mineralization (JSM 6390LV)). Findings. A model of pyrite-polymetallic mineralization genetically related to the Devonian basalt-andesite-rhyolite Early Hercynian riftogenic volcanism (D1e-D3fr) was developed. Originality. The spatial confinement of a number of industrial deposits, areas of sulfide mineralization and near-ore-hydrothermally altered rocks to the areas of pinching out of inter- and sub-stratal subvolcanic porphyries of the Middle Upper Devonian and overlying porphyrites, creating a kind of ore-magmatic systems (OMS), has been established. Practical value. A new stage of deep geological study on the territory of the Rudny Altai and promising ore-bearing structures with the introduction of modern methods of deep geological and mineragenic mapping is recommended.

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