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 Retrogression of Orthopyroxene-bearing Gneiss of Iboropa Akoko, Southwestern Nigeria

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
E.J. Oziegbe ◽  
V.O. Olarewaju ◽  
O.O. Ocan ◽  
G. Costin
Keyword(s):  
Granulite Facies ◽  
Mineral Chemistry ◽  
Accessory Mineral ◽  
High Concentration ◽  
Southwestern Nigeria ◽  
Eu Anomaly ◽  
Mineral Assemblages ◽  
The Relationship ◽  
Rehydration Process ◽  
Alkali Feldspars

AbstractIn this article, we report the mineral chemistry and petrographic features of charnockitic exposure of Iboropa within Precambrian Basement Complex of Nigeria. The mineral assemblages are pyroxene, plagioclase, biotite, hornblende, alkali feldspars, microperthite, quartz and ilmenite, with apatite occurring as accessory mineral. Apatite occurs in abundance as euhedral crystals. Orthopyroxene observed is strongly pleochroic and has numerous microfractures, and it is hypersthene (En45Fs54Wo1) with low TiO2 and MnO, having extremely low percentage of CaO. Hypersthene is mantled by a complex corona of amphibole, and the amphibole is hornblende with a chemical formula: (K,Na)(Ca,Fe)2 (Fe,Mg,Al,Ti)5(Al,Si)8O22(OH)2. Plagioclase occurs as inclusions in both pyroxene and biotite. Biotite has high concentration of TiO2 and extremely low CaO. The opaque mineral observed is ilmenite and it is concentrated around hypersthene and amphibole. Rare earth element (REE) displays negative Eu anomaly with enrichment of light REE over heavy REE. Amphiboles surrounding orthopyroxene are evidences of retrograde reactions and are formed at the expense of orthopyroxene reacting with plagioclase and quartz in the presence of fluid. The relationship between the mineral assemblages suggests the retrogression of the gneiss that might be as a result of rehydration process, and it is a transition from granulite facies to amphibolite facies during a retrogressive form of metamorphism.

scholarly journals Geochemical signatures of mineralizing events in the Juomasuo Au–Co deposit, Kuusamo belt, northeastern Finland

2021 ◽  
Author(s):  
Mikael Vasilopoulos ◽  
Ferenc Molnár ◽  
Hugh O’Brien ◽  
Yann Lahaye ◽  
Marie Lefèbvre ◽  
...  
Keyword(s):  
Trace Element ◽  
Sulfur Isotope ◽  
Mineral Chemistry ◽  
Chemical Compositions ◽  
Metasedimentary Rocks ◽  
Metavolcanic Rocks ◽  
Icp Ms ◽  
Stage 1 ◽  
Host Rocks ◽  
Relationship Of

AbstractThe Juomasuo Au–Co deposit, currently classified as an orogenic gold deposit with atypical metal association, is located in the Paleoproterozoic Kuusamo belt in northeastern Finland. The volcano-sedimentary sequence that hosts the deposit was intensely altered, deformed, and metamorphosed to greenschist facies during the 1.93–1.76 Ga Svecofennian orogeny. In this study, we investigate the temporal relationship between Co and Au deposition and the relationship of metal enrichment with protolith composition and alteration mineralogy by utilizing lithogeochemical data and petrographic observations. We also investigate the nature of fluids involved in deposit formation based on sulfide trace element and sulfur isotope LA-ICP-MS data together with tourmaline mineral chemistry and boron isotopes. Classification of original protoliths was made on the basis of geochemically immobile elements; recognized lithologies are metasedimentary rocks, mafic, intermediate-composition, and felsic metavolcanic rocks, and an ultramafic sill. The composition of the host rocks does not control the type or intensity of mineralization. Sulfur isotope values (δ34S − 2.6 to + 7.1‰) and trace element data obtained for pyrite, chalcopyrite, and pyrrhotite indicate that the two geochemically distinct Au–Co and Co ore types formed from fluids of different compositions and origins. A reduced, metamorphic fluid was responsible for deposition of the pyrrhotite-dominant, Co-rich ore, whereas a relatively oxidized fluid deposited the pyrite-dominant Au–Co ore. The main alteration and mineralization stages at Juomasuo are as follows: (1) widespread albitization that predates both types of mineralization; (2) stage 1, Co-rich mineralization associated with chlorite (± biotite ± amphibole) alteration; (3) stage 2, Au–Co mineralization related to sericitization. Crystal-chemical compositions for tourmaline suggest the involvement of evaporite-related fluids in formation of the deposit; boron isotope data also allow for this conclusion. Results of our research indicate that the metal association in the Juomasuo Au–Co deposit was formed by spatially coincident and multiple hydrothermal processes.

scholarly journals Rare and Critical Metals in Pyrite, Chalcopyrite, Magnetite, and Titanite from the Vathi Porphyry Cu-Au±Mo Deposit, Northern Greece

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 630
Author(s):  
Christos L. Stergiou ◽  
Vasilios Melfos ◽  
Panagiotis Voudouris ◽  
Lambrini Papadopoulou ◽  
Paul G. Spry ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Mineral Chemistry ◽  
Critical Metals ◽  
Northern Greece ◽  
Inductively Coupled ◽  
Porphyry Cu ◽  
Icp Ms ◽  
Quartz Monzonite ◽  
Ore Minerals ◽  
Plasma Mass Spectrometry

The Vathi porphyry Cu-Au±Mo deposit is located in the Kilkis ore district, northern Greece. Hydrothermally altered and mineralized samples of latite and quartz monzonite are enriched with numerous rare and critical metals. The present study focuses on the bulk geochemistry and the mineral chemistry of pyrite, chalcopyrite, magnetite, and titanite. Pyrite and chalcopyrite are the most abundant ore minerals at Vathi and are related to potassic, propylitic, and sericitic hydrothermal alterations (A- and D-veins), as well as to the late-stage epithermal overprint (E-veins). Magnetite and titanite are found mainly in M-type veins and as disseminations in the potassic-calcic alteration of quartz monzonite. Disseminated magnetite is also present in the potassic alteration in latite, which is overprinted by sericitic alteration. Scanning electron microscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of pyrite and chalcopyrite reveal the presence of pyrrhotite, galena, and Bi-telluride inclusions in pyrite and enrichments of Ag, Co, Sb, Se, and Ti. Chalcopyrite hosts bornite, sphalerite, galena, and Bi-sulfosalt inclusions and is enriched with Ag, In, and Ti. Inclusions of wittichenite, tetradymite, and cuprobismutite reflect enrichments of Te and Bi in the mineralizing fluids. Native gold is related to A- and D-type veins and is found as nano-inclusions in pyrite. Titanite inclusions characterize magnetite, whereas titanite is a major host of Ce, Gd, La, Nd, Sm, Th, and W.

Paleoredox conditions, hydrothermal history, and target vectoring in the Macmillan Pass base-metal district, Yukon, Canada: 2 – Pyrite paragenesis and mineral chemistry

2021 ◽  
Vol 59 (5) ◽  
pp. 1233-1259
Author(s):  
Claire Leighton ◽  
Daniel Layton-Matthews ◽  
Jan M. Peter ◽  
Michael G. Gadd ◽  
Alexandre Voinot ◽  
...  
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Mineral Chemistry ◽  
Hydrothermal Activity ◽  
Unconsolidated Sediments ◽  
Lateral Migration ◽  
Sulfide Mineralization ◽  
Ambient Seawater ◽  
Clastic Sediment ◽  
Icp Ms

ABSTRACT The MacMillan Pass district in Yukon, Canada, hosts the Tom and Jason clastic sediment-hosted Zn-Pb-Ag-(Ba) deposits. Pyrite-bearing drill core samples were collected from seven drill holes that intersected sulfide mineralization and time-stratigraphically equivalent rocks at varied spatial distances extending up to 3 km away from the deposits to assess the relative timing of pyrite mineralization and the chemistry of pyrite paragenesis. There are four pyrite morphologies: framboids and polyframboids (Py1), subhedral to euhedral inclusion-free crystals (Py2a), silicate inclusion-bearing nodules with serrated edges (Py2b), and euhedral idiomorphic overgrowths on preexisting pyrite morphologies (Py3). These morphological varieties correspond in time from syngenetic to earliest diagenetic growth (Py1), early to late diagenetic growth (Py2a, Py2b), and metamorphic crystallization and/or recrystallization of previous textural varieties (Py3). A representative subset of pyrite grains was analyzed for trace element contents and distributions by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Analyses by LA-ICP-MS reveal that each textural variety of pyrite has a distinct trace element composition that also varies depending on stratigraphic unit. A suite of clastic sediment-hosted sulfide mineralization-related elements was incorporated into Py2 within sulfide mineralized units at greater abundances than that in unmineralized units (e.g., Zn, As, Pb, Tl, Bi). Lead abundances and Pb/Se and As/Mo values in pyrite are the most robust vectoring tools documented. The timing for clastic sediment-hosted Zn-Pb mineralization was syn and/or post late diagenesis (Py2b). A Ba-enriched horizon was identified in rocks and this is interpreted to be the distal time-stratigraphic equivalent unit to Zn-Pb mineralization. The Ba-enriched horizon contains Py2 with anomalous metal (Tl, Co, Mn, Cd, Zn, Sb) contents and abundant macroscopic baryte, and it is interpreted to represent the distal expression of sulfide mineralization-forming hydrothermal activity. Four genetic models for mineralization are reviewed; however, the only model that is consistent with our whole rock and pyrite geochemistry involves venting of buoyant hydrothermal fluid, mixing with ambient seawater, and remaining or sinking into unconsolidated sediments, with lateral migration up to 2–3 km from the vent source.

scholarly journals Influence of Fuel Chemical Properties on Soot Emissions From Gas Turbine Combustors

1989 ◽  
Author(s):  
J. S. Chin ◽  
A. H. Lefebvre
Keyword(s):  
Chemical Composition ◽  
Gas Turbine ◽  
Hydrogen Content ◽  
Continuous Flow ◽  
Empirical Relationship ◽  
Chemical Properties ◽  
Smoke Point ◽  
Fuel Composition ◽  
Wide Range ◽  
Soot Emissions

The influence of fuel composition on soot emissions from continuous flow combustors is examined. A study of the combustion characteristics of a wide range of present and potential aviation fuels suggests that smoke point provides a better indication of sooting tendency than does hydrogen content. It is concluded from this study that the best empirical relationship between fuel chemical composition and soot emissions is one which combines two fuel composition parameters — smoke point and naphthalene content — into a single parameter which is shown to correlate successfully soot emissions data acquired from several different fuels burning in a variety of gas turbine and model combustors.

Investigation into the Differences Chemical Properties of Laser Sintering Polymer Powders Using Fourier Transform Infrared Spectroscopy

2014 ◽  
Vol 548-549 ◽  
pp. 133-136
Author(s):  
Yusoff Way ◽  
Hadi Puwanto ◽  
Farizahani ◽  
P.T. Pham
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Chemical Composition ◽  
Fourier Transform Infrared Spectroscopy ◽  
Surface Finish ◽  
Chemical Properties ◽  
Fourier Transform Infrared ◽  
Laser Sintering ◽  
Polymer Materials ◽  
Powder Materials

Selective Laser Sintering (SLS) or Laser Sintering (LS) allows functional parts to be produced in a wide range of powdered materials using a dedicated machine, and is thus gaining popularity within the field of Rapid Prototyping (RP). One of the advantages of employing LS is that the loose powder of the building chamber can be recycled. The properties of polymer powder significantly influence the melt viscosity and sintering mechanism during Laser Sintering (LS) processes which results in a good surface finish. The objective of this research is to investigate the chemical composition of fresh polymer materials used in Laser Sintering. There are seven virgin SLS materials which are PA2200, GF3200, Alumide, PrimeCast, PrimePart, Duraflex and CastForm. Fourier Transform Infrared Spectroscopy (FTIR) was used to analyze the chemical composition of the materials by using infrared radiation and absorbed frequency. The spectra show that similar functional groups were found in the materials apart from PrimePart and Duraflex. Obtained data from this analysis could be used to investigate on how the fresh and recycled powder materials with different chemical properties would affect the part surface finish.

scholarly journals Petrogenetic and Compositional Features of Rare Metal Pan-African Post-Collisional Pegmatites of Southwestern Nigeria; A Status Review

2018 ◽  
Vol 7 (2) ◽  
pp. 166-187
Author(s):  
Abiola Oyebamiji ◽  
Adeniyi JohnPaul Adewumi ◽  
Tehseen Zafar ◽  
Adegbola Odebunmi ◽  
Philips Falae ◽  
...  
Keyword(s):  
Mineral Chemistry ◽  
Rare Metal ◽  
Border Zone ◽  
Chemical Compositions ◽  
Molten Material ◽  
Southwestern Nigeria ◽  
Pan African ◽  
Opening And Closing ◽  
High Degree ◽  
Rare Metal Pegmatite

Abstract This research reviews the geology, petrogenesis, compositional trends and geochronology of the rare-metal pegmatite of southwestern Nigeria. The source of these pegmatites is still presently debated which have been explained as either product of highly fractionated molten material or anatexis of the local crust. However, published works of past authors have been compiled to give a detailed understanding of the formation of the mineral deposits. The basement complex of southwestern Nigeria comprises of Precambrian rocks of amphibolite, the hornblende gneiss and the granite gneisses which were formed as a result of the opening and closing of the ensialic basin with significant, extensive subduction during the Pan-African orogeny. The pegmatites in this region have shown internal zoning and a high degree of evolution from the border zone to the core zone during the crystallization and solidification of the felsic granite to pegmatite melt. The rare-metal pegmatites have distinct chemical compositions and mineralogy, containing quartz, biotite, muscovite, microcline, garnet with localized tourmaline, tantalite and columbite. These pegmatites vary significantly by their bulk-rock and mineral chemistry which indicates a more peraluminous attribute and enrichments of lithophile elements of Rb, Cs, Ta and Ba. Previous K/Ar isotopic ages (502.8±13.0 Ma and 514.5±13.2 Ma) suggest that the pegmatites are related to the post-collisional phase of intensive metasomatism. Adopted from previous studies, a five-stage conceptual model of evolution which is widely accepted have been proposed for the origin of the pegmatites.

scholarly journals Adaptability and stability of white oat cultivars in relation to chemical composition of the caryopsis

2013 ◽  
Vol 48 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Maraisa Crestani Hawerroth ◽  
Fernando Irajá Félix de Carvalho ◽  
Antonio Costa de Oliveira ◽  
José Antonio Gonzalez da Silva ◽  
Luiz Carlos Gutkoski ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Avena Sativa ◽  
Block Design ◽  
Chemical Properties ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Average Performance ◽  
Randomized Block Design ◽  
Nitrogen Free Extract ◽  
Oat Cultivars

The objective of this work was to characterize the chemical properties of white oat (Avena sativa) caryopsis and to determine the adaptability and stability of cultivars recommended for cultivation in the state of Rio Grande do Sul, Brazil. The trials were carried out in the 2007, 2008 and 2009 crop seasons, in three municipalities: Augusto Pestana, Capão do Leão, and Passo Fundo. Fifteen cultivars were evaluated in a randomized block design, with four replicates. The contents of protein, lipid, and nitrogen-free extract were evaluated in the caryopsis. Cultivar performances for the measured characters varied according to location and year of cultivation. The cultivar URS Guapa showed high content of nitrogen-free extract and low contents of protein and lipid in the caryopsis. 'FAPA Louise' showed high content of lipid, whereas 'Albasul', 'UPF 15', and 'UPF 18' showed high content of protein and low content of nitrogen-free extract. There is no evidence of an ideal biotype for the evaluated characters, which could simultaneously show high average performance, adaptability to favorable and unfavorable environments, and stability.

scholarly journals Compositional and industrial assessment of Isua-Akoko, Akure, Ayadi and Lafe (Ode Aye) clay deposits of Ondo state, Nigeria

1970 ◽  
Vol 21 (1) ◽  
pp. 41-49
Author(s):  
O Adegbuyi ◽  
GP Ojo ◽  
AJ Adeola ◽  
MT Alebiosu
Keyword(s):  
Chemical Properties ◽  
Fine Sand ◽  
Coarse Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Medium Sand ◽  
Southwestern Nigeria ◽  
Firing Test ◽  
Clay Deposits ◽  
Ondo State

The physical and chemical properties of clay deposits around Isua-Akoko, Akure, Lafe and Ayadi in Ondo State southwestern Nigeria have been examined. The results have shown that Isua-Akoko, Akure and Lafe Clays are plastic fire clays while Ayadi clay is kaolinite. Grain size analysis reveals that Isua Akoko Clay contains 45% of clay, 18% silt, 12% fine sand,14% medium sand and 11% coarse sand and no gravel; Akure clay contains 42% clay, 14% silt, 13% fine sand, 20% medium sand and 8% coarse sand with 1% gravel. Lafe Clay contains 21% clay, 8% silt, 25% fine sand, 37% medium sand and 8% coarse sand with 1% gravel while Ayadi clay contains 83% clay and 17% silt. The liquid limits of these clay samples range from 41% to 73%% and plastic limits range from 18% to 26% respectively. The chemical analysis reveals that the most abundant mineral is silica (60.97%) and aluminum was next in abundance (23.69%) while other oxides are low. The results show that Isua-Akoko and Akure are residual while Lafe and Ayadi are sedimentary and transported Clays. The firing test, PH, and bleaching tests of the clays are also discussed. The chemical and physical characteristics of the clay deposits are strongly indicative of their industrial importance in the production of ceramics, refractories, paving bricks, paint and pharmaceutical products.KEYWORDS: Kaolinite, fire clay, gravel, ceramics and alumina.

Sign in / Sign up

Export Citation Format

Share Document