scholarly journals Petrographical and mineral chemistry characteristics of mafic dykes in Nhi Ha area, Ninh Thuan and its meaning

2020 ◽  
Vol 2 (6) ◽  
pp. 201-213
Author(s):  
Nguyen Minh Tai ◽  
Pham Trung Hieu
Keyword(s):  
Chemical Analysis ◽  
Hydrothermal Alteration ◽  
Mineral Chemistry ◽  
Block Type ◽  
Mafic Dyke ◽  
Quaternary Sediment ◽  
Mafic Dykes ◽  
Dyke Rock ◽  
Alteration Minerals ◽  
Opaque Minerals

The NE-SW and NW-SE mafic dyke rocks in Nhi Ha area intruded through Cretaceous granitoid Dinh Quan or overlapped by Quaternary sediment materials. It has block type and blue grey in color in the field. Under microscope, based on minerals and textures, divided into 2 types of mafic dyke rock, such as diabase and porphyritic diabase. Minerals chemical analysis by EPMA method: plagioclase almost are labradorite (An 60.80%), oligoclase (An from 12.31 to 14.29%), some grain had albitation (An from 6.75 to 8.46%); pyroxene with augite (Wo41,80 En44,22 Fs13,98 to Wo43,40 En37,50 Fs19,10) and diopsite composition (Wo45,45 En42,48 Fs12,07 to Wo48,16 En40,02 Fs11,81); amphiboles in basalt are magnesio-hastingsite (Ca-amphibole group). Popular alteration minerals are chlorite, epidote and sericite. Chlorite is pycnochlorite type, ratio Fe/(Fe+Mg) <0,6 show that it formed by hydrothermal alteration process with temperature from 150 to 3250C. Opaque minerals are pyrite, chalcopyrite, ilmenite, magnetite, titanomagnetite, titanite (sphene) and a little bit of rutile.  

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 PLUMBIAN "ALUNITES" IN HYDROTHERMAL ALTERATION ZONES OF EPITHERMAL AND PORPHYRY TYPE MINERALIZATIONS IN W. THRACE

2004 ◽  
Vol 36 (1) ◽  
pp. 492 ◽  
Author(s):  
Π. Βουδούρης ◽  
Κ. Αρίκας ◽  
Α. Κατερινόπουλος
Keyword(s):  
Hydrothermal Alteration ◽  
Solid Solutions ◽  
Mineral Chemistry ◽  
Alteration Zones ◽  
Hydrothermal Alteration Zones ◽  
Hydrothermal Environment

In this study a new occurrence of Pb-rich members of the alunite supergroup minerals is described. The "alunites" were traced in advanced argilic alteration zones of epithermal and porphyry type mineralizations in W. Thrace/(Greece). These "alunites" are Ca-Sr-Ba-Pb-rich phosphatessulfates and represent solid solutions between members of the alunite, woodhouseite and crandallite group minerals. The highest concentrations of PbO in the Mavrokoryfi and Melitaina alunites are 24.7% and 17.4% respectively. The plumbian phosphates-sulfates occur in the cores of the crystals and are surrounded by common K-Na-rich alunites in Mavrokoryfi and Ba-rich woodhouseite in Melitena, an indication that they were formed in a magmatic-hydrothermal environment after dissolution of apatite and feldspars by phosphate-sulphate rich solutions. The mineral-chemistry of these "alunites" can provide information regarding the genesis of the advanced argilic alteration zones in Greece, and help us in the distinction of the epithermal from deep porphyry style environments.

scholarly journals Nahrwan Clays Study for Brick Industry

2008 ◽  
Vol 5 (4) ◽  
pp. 538-544
Author(s):  
Baghdad Science Journal
Keyword(s):  
Compressive Strength ◽  
Chemical Analysis ◽  
Moisture Content ◽  
Physical Properties ◽  
Clay Brick ◽  
Quaternary Sediment ◽  
Physical Test ◽  
Class A ◽  
Clay Deposits ◽  
Depth Ranges

Nahrawan clay deposits lies in Diyala governorate , 65 Km, NE of Baghdad , according to the previous work in this field, in which they study the reserve belong to category of investigation ( C2 & C1 ) , we choice the proper area to investigation of category (B) with drill net( 200x 200m ) to rise the amount of reserve. The investigation work included drilling (116) boreholes of total depth ranges from (10.0-12.55m) , showed mainly clayey and silty deposits with little sand , and the typical borehole (648) represents all types of sediment in the area , and most of boreholes without sandy deposits , and all of these deposits is Quaternary sediment which is consist of two main sedimentary cycles ( the Pleistocene & Holocene ) . Chemical analysis for (343) samples were done , and physical test carried on ( 143 ) samples , and all show suitable properties for clay brick industry . the area of investigation covered ( 5.200.000 m2) involving ( 620.000 m2 ) containing soluble salt more than ( 3.5%) , which was separated from the total area , so the residual (4.580.000m2 ) had been taken to calculate the reserve , with depth of ( 10.76m) for the industrial clay bed . The reserve calculations depended on the following chemical & physical Properties: The chemical analysis shows that , CaO ( 16.53%) MgO ( 4.65% ) , SO3 ( 1.42%) , T.S.S. (2.42%) , the physical properties are unfired properties Which contains Bulk density ( 2.09gm/cm3) , moisture content (20.95%) , linear dry shri. (7.63%) , and fired properties which contain water absorption (18.8%) , linear shri. (0.8%) volume shri. (2.212% ) , compressive strength ( 468.606Kg/cm2) . So the reserve of category (B) is ( 49.280. 800 m3 ) or (102.966.000 Ton) the physical test showed that the brick classified into class (A-B) .

Mineral chemistry and geothermobarometry of the Balıkesir Volcanites (NW Anatolia, Turkey) 

2021 ◽  
Author(s):  
Alp Ünal ◽  
Şafak Altunkaynak
Keyword(s):  
Mineral Composition ◽  
Magma Chamber ◽  
Magma Mixing ◽  
Textural Properties ◽  
Mineral Chemistry ◽  
Oscillatory Zoning ◽  
Magma Chamber Processes ◽  
Crystallization Conditions ◽  
Compositional Variations ◽  
Opaque Minerals

&lt;p&gt;Bal&amp;#305;kesir Volcanites (BV) are included into the Bal&amp;#305;kesir Volcanic Province and contain various products of Oligo-Miocene volcanic activity in NW Anatolia. BV are formed from trachyandesite, andesite and dacite lavas with associated pyroclastic rocks. In this study, we report the petrographical investigations, mineral chemistry results and geothermobarometry calculations of the Bal&amp;#305;kesir Volcanites in order to deduce the magma chamber processes and crystallization conditions. Andesites present a mineral composition of plagioclase (An35&amp;#8211;50) + amphibole (edenitic hornblende) +biotite &amp;#177; quartz and opaque minerals. The major phenocryst phases in dacite lavas are plagioclase (An39&amp;#8211;53), quartz, amphibole (magnesio-hornblende), biotite, sanidine and opaque minerals. The mineral composition of the trachyandesites, on the other hand, is represented by plagioclase (An38&amp;#8211;57) + amphibole (pargasitic hornblende) + biotite + clinopyroxene (endiopside- augite) &amp;#177; sanidine &amp;#177; quartz &amp;#177; opaque minerals. Bal&amp;#305;kesir Volcanites present distinct textural properties such as rounded plagioclase phenocrysts with reaction rims, oscillatory zoning, honeycomb and sieve textures in plagioclase, reverse mantled biotite and hornblende crystals. The plagioclase- amphibole geothermobarometry calculations of Bal&amp;#305;kesir volcanites indicate that, andesite and dacite lavas present similar crystallization temperature and pressures conditions of 798- 813&amp;#176;C and 1,98- 2.17 kbar. Oppositely, trachyandesites were crystallized under 857&amp;#176;C and 3,72 kbar temperature and pressure conditions. These results show that the andesite and dacite lavas were originated from the same magma chamber with the depth of 7km whereas trachyandesites were evolved in a deeper magma chamber with 13 km depth. Combined mineral chemistry, petrography and geothermobarometry studies indicate that the open system processes such as magma mixing/mingling and/or assimilation fractional crystallization (AFC) were responsible for the textural and compositional variations of the Bal&amp;#305;kesir Volcanites.&lt;/p&gt;

Lithium-Bearing Hydrothermal Alteration Phyllosilicates Related to Portalet Fluorite Ore (Pyrenees, Huesca, Spain)

Clay Minerals ◽  
1993 ◽  
Vol 28 (2) ◽  
pp. 275-283 ◽  
Author(s):  
J. M. Gonzlez Lopez ◽  
I. Subias Pirez ◽  
C. Fernandez-Nieto ◽  
I. Fanlo Gonzalez
Keyword(s):  
Hydrothermal Alteration ◽  
Half Cell ◽  
Ore Bodies ◽  
Alteration Minerals ◽  
Structural Formulae

AbstractPhyllosilicate associations in hydrothermally altered fluorite ore bodies are: Li-chlorite ± pyrophyllite ± interstratified minerals ± muscovite +± kaolinite. Chlorites, the main alteration minerals, are dioctahedral, d060 = 1.489-1-490/~,, of Ia polytype. The structural formulae indicate substitution of AI for Si from 0.61-0.78 atoms. The total octahedral occupancy ranges from 4.52-4-71 atoms, with 0.49-0-69 Li atoms per half cell unit. This composition indicates that the chlorites are intermediate members of the donbassite-cookeite series proposed by Sudo (1978). The mineralogical associations and textural relations suggest that after intensive silicification which produced alkali alteration under acid conditions, pyrophyllite was produced at the expense of muscovite and then Li-bearing donbassite formed from the pyrophyllite. The Li needed for the formation of the chlorites could be genetically related to granitic batholiths which occur close to the fluorite ores.

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