Caracteres petrographiques de l'ophite de Vebre (Ariege)

1965 ◽  
Vol S7-VII (1) ◽  
pp. 168-171
Author(s):  
Ch Riotte ◽  
Jean Thiebaut
Keyword(s):  
Basaltic Magma ◽  
Petrographic Analysis ◽  
Chemical Analyses ◽  
Rock Types ◽  
The Right ◽  
Potassium Enrichment ◽  
Later Phase

Abstract Petrographic analysis of the ophite outcrop on the right bank of the Ariege river, below Vebre, France, shows that the rock is rich in epidote and exhibits pegmatoid differentiation. Three rock types are distinguished--common ophite with variable amounts of epidote; ophite with phlogopite; and pegmatoid rocks with orthoclase. The results of four chemical analyses indicate that the Vebre ophites were affected by pneumatolysis during crystallization from a saturated basaltic magma. The pneumatolysis caused the crystallization of hornblende and, in a later phase of potassium enrichment, the superimposition of orthoclase in the pegmatoid plagioclases and the phlogopite in the hornblende crystals of the ophite.

GEOLOGICAL STUDY AND MINING PLAN IMPORTANCE FOR MITIGATING ALKALI SILICA REACTION IN AGGREGATE QUARRY OPERATION

2016 ◽  
Vol 78 (7-3) ◽  
Author(s):  
Edy Tonnizam Mohamad ◽  
Bhatawdekar Ramesh Murlidhara ◽  
Mohd Nur Asmawisham Bin Alel ◽  
Danial Jahed Armaghani
Keyword(s):  
Aggregate Demand ◽  
Peninsular Malaysia ◽  
Alkali Silica Reaction ◽  
Petrographic Analysis ◽  
Kuala Lumpur ◽  
Developing Regions ◽  
Geological Structures ◽  
Rock Types ◽  
Mine Plan

More than 80 million tonnes of construction aggregate are produced in Peninsular Malaysia. Majority of construction aggregate are produced from granite. Developing regions of Johor Bahru, Kuala Lumpur, Penang and Selangar utilize granite aggregates. Normally it is considered aggregates as non-alkali reactive. Geological study can identify various rock types, geological structures, and reactive minerals which contribute to Alkali Silica Reaction (ASR). Deformed granites formed through faulting results in reduction of quartz grain size. Microcrystalline quartz and phyllosilicates are found in granites in contact with country rocks. Secondary reactive minerals such as chalcedony and opal may be found in granite. Alkali Silica reaction is slow chemical reaction in concrete due to reactive silica minerals in aggregates, alkalis in cement and moisture. For long term durable concrete, it is essential to identify potential alkali silica reactive aggregates. Lack of identifying reactive aggregates may result spalling, cracking in concrete and ultimately ASR can result in hazard to concrete structure. This paper deals with geological study of any aggregate quarry to identify rock type and geological structures with laboratory test –petrographic analysis and bar mortar test can identify type of aggregates being produced. Mine plan with Surpac software can be developed for systematic working for aggregate quarry to meet construction aggregate demand.

scholarly journals Petrographic analysis of carbonate rocks for alkali-aggregate reactivity

1970 ◽  
Vol 14 ◽  
pp. 15-20
Author(s):  
Naresh Kazi Tamrakar ◽  
Lalu Prasad Paudel
Keyword(s):  
Rock Sample ◽  
Rock Type ◽  
Significant Proportion ◽  
Carbonaceous Material ◽  
Petrographic Analysis ◽  
Rock Types ◽  
Alkali Silica Reactivity ◽  
Alkali Carbonate ◽  
Alkali Aggregate Reactivity

Quality of aggregate is of extreme concern when it is to be used for infrastructures. Besides, many physical and mechanicalproperties of the aggregate, presence or absence of deleterious constituents and alkali-silica reactivity are especially importantwhen aggregates are to be used in concrete structures. High potential of alkali-silica reactivity or alkali-carbonate reactivity andpresence of deleterious constituents may impair the infrastructures.A ledge rock sample from the heap to be taken for crushing was petrographically analysed for alkali-silica reactivity. Inoverall, two rock clans (dolosparstone and dolomicrosparstone) with three sub clans (rock type X, Y and Z) from the sample 2 areidentified. Rock type X (dolosparstone) constitutes 82.94% of the whole sample, and shows notable amount of quartz and calciteveins, and carbonaceous material and hematite on the mosaic of dolospars. Rock types Y (dolosparstone) and Z (dolomicrosparstone)contain trace amount of microquartz, mega quartz (>15 mm) and carbonaceous opaques. The rock type Z is dominantly composedof dolomicrospars. Major portions of all the rock types are characterised by mosaics of dolomite in association with variableamounts of muscovite, quartz, and calcite. Calcite often replaces the mosaics of dolomite and bands of quartz, forming a veinnetworks in rock types X and Y. Silica is represented by a low-temperature mega quartz either in ground or in veins, a trace amountof microquartz in rock types Y and Z. There is no other reactive silica components, thus showing a low potential to alkali-silicareactivity. However, the sample shows potential of alkali-carbonate reactivity as significant proportion of rock type havingdolomicrospars are found.DOI: http://dx.doi.org/10.3126/bdg.v14i0.5433Bulletin of the Department of Geology Vol.14 2011, pp.15-20

A Grenville-age layered intrusion in the subsurface of west Texas: petrology, petrography, and possible tectonic setting

1995 ◽  
Vol 32 (12) ◽  
pp. 2159-2166 ◽  
Author(s):  
Hulusi Kargi ◽  
Calvin G. Barnes
Keyword(s):  
Tectonic Setting ◽  
Basaltic Magma ◽  
Layered Intrusion ◽  
Mafic Magma ◽  
Magma Source ◽  
Rock Types ◽  
Hornblende Gabbro ◽  
Tectonic Environment ◽  
Extensional Tectonic ◽  
General Order

The Nellie intrusion is a thick (more than 4420 m) mafic to ultramafic layered intrusion with a radiometric age of ~1163 Ma. Rock types change abruptly with stratigraphic height and include norite, pyroxenite, gabbronorite, hornblende gabbro, gabbro, anorthosite, harzburgite, and lherzolite. Norite is most abundant, but gabbro and hornblende gabbro are locally abundant. Rare olivine-rich layers are also present. The general order of crystallization was olivine, orthopyroxene, plagioclase + clinopyroxene, and hornblende. Mg#'s, expressed as 100 Mg/(Mg + Fe), range from 76.3 to 85.8 for olivine, 56.7 to 84.9 for orthopyroxene, 62.5 to 90.3 for clinopyroxene, and 52.4 to 82.8 for amphibole. Mg#'s vary with height and display abrupt reversals, which indicate open-system addition of new mafic magma. Eleven cyclic units were identified on the basis of evidence for injection of basaltic magma; these can be grouped into three megacyclic units. The abundance of orthopyroxene, and mineral compositional evidence for Fe enrichment within cyclic units, indicates that parental magmas were subalkaline and tholeiitic. Plagioclase in equilibrium with olivine ranges from An65 to An46, which precludes an arc-related magma source. Although the intrusion is approximately coeval with Keweenawan magmatism and with emplacement of diabasic dikes in western North America, it is dissimilar in detail to both suites of rocks. Nevertheless, its composition and geophysical setting are consistent with emplacement in an extensional tectonic environment.

The Idea of Contrasted Differentiation

1936 ◽  
Vol 73 (5) ◽  
pp. 228-238 ◽  
Author(s):  
Arthur Holmes
Keyword(s):  
Basaltic Magma ◽  
Necessary Condition ◽  
Residual Liquid ◽  
Continuous Separation ◽  
Intermediate Composition ◽  
Rock Types ◽  
Crystallization Differentiation ◽  
Intermediate Layers ◽  
Intermediate Rock ◽  
Basic Rocks

As early as 1915, it was made clear by Bowen that, given continuous separation of crystals from the successive residual liquids of a consolidating magma which was initially basaltic in composition, the inevitable result would be a gabbroic rock in depth, a granitic one above, and “various intermediate types in the intermediate layers”. As a necessary condition to the evolution of a magmatic residuum of granitic composition, this process of progressive crystallization differentiation involves the generation of intermediate rock-types from residual liquids of intermediate composition. Certain investigators, however, led by the authors of the Mull memoir (1924), have entirely overlooked the necessity of this condition. Faced with the association of contrasted acid and basic rocks, which is a conspicuous characteristic of many continental central complexes, they have attempted to account for the facts by introducing a modified conception of crystallization differentiation for which Nockolds has recently proposed the name contrasted differentiation. According to this conception, the residual liquid of consolidating basaltic magma is of granitic composition and can be separated in bulk from a crystalline gabbroic phase.

scholarly journals Petrology of Exposed Basement Rocks around Shintaku of North Central Nigeria

2013 ◽  
Vol 5 (3) ◽  
pp. 489-497
Author(s):  
O. Odedede
Keyword(s):  
Granite Gneiss ◽  
Mineralogical Composition ◽  
Petrographic Analysis ◽  
Structural Elements ◽  
North Central ◽  
Porphyritic Granite ◽  
Geologic Time ◽  
Rock Types ◽  
Basement Rocks ◽  
Porphyritic Texture

The study area is part of the Basement Complex of North Central Nigeria. The study aims at identifying the rock types and interpretation of the structural elements. The major rock units in the area comprises of porphyritic granite, gneiss and schist. Structural evidence shows that the rocks are deformed and where intruded by the granite. Petrographic analysis reveals the existence of feldspar phenocrysts in a groundmass of quartz and biotite. The granite is composed of quartz (25-35%), plagioclase (15-20%), orthoclase (10-20%), microcline (5-25%), biotite (15-20%) and other accessory minerals. The granites displayed a porphyritic texture while the schist and gneisses exhibit planar and linear structures. Variation in structural trend and mineralogical composition is due to the series of deformational activities which has affected the rocks during geologic time. Keywords: Monzogranite; Porphyritic; Deformation; Fractionation.  © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.  doi: http://dx.doi.org/10.3329/jsr.v5i3.15233 J. Sci. Res. 5 (3), 489-497 (2013)  

scholarly journals Multiscale Characterization of the Caney Shale — An Emerging Play in Oklahoma

2021 ◽  
Vol 2 ◽  
pp. 33-53
Author(s):  
Yulun Wang ◽  
Guofan Luo ◽  
Mercy Achang ◽  
Julie Cains ◽  
Conn Wethington ◽  
...  
Keyword(s):  
Clay Content ◽  
High Energy ◽  
Rock Properties ◽  
Carbonate Content ◽  
Petrographic Analysis ◽  
Thin Sections ◽  
X Ray ◽  
Rock Types ◽  
Rebound Hardness

From a hydrocarbon perspective, the Caney Shale has historically been evaluated as a sealing unit, which resulted in limited studies characterizing the rock properties of the Caney Shale and its suitability for hydraulic fracturing. The objective of our research is to help bridge the current knowledge gap through the integration of multiscale laboratory techniques and to characterize the macro- and microscale rock properties of the Caney Shale. We employed an integrated approach for the characterization of the Caney using 200 ft (61 m) of Caney core from a target well in southern Oklahoma. Core observation and petrographic analysis of thin sections were combined to characterize the general rock types and associated fabrics and textures. Mineralogical composition, pore system architecture, and rock fabric were analyzed using x-ray diffraction (XRD), scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS), and focused ion beam (FIB)-SEM. In addition, rebound hardness and indentation testing were carried out to determine rock hardness (brittleness) and elasticity, respectively. With the integrated multiscale characterization, three mixed carbonate-siliciclastic rock types were identified — mudstone, calcareous siltstone, and silty carbonate — likely representing a spectrum of deposition from low to relatively high energy environments in the distal portions of a ramp system. Silty carbonate contains mostly interparticle pores. The calcareous siltstones and silty mudstones contain a combination of organic matter pores and interparticle pores. Each of the rock types shows unique mineralogical compositions based on XRD. The mudstone lithofacies has the highest clay content and the least carbonate content. Calcareous siltstones show moderate carbonate and clay content. Silty carbonate indicates the highest carbonate content with the least clay content. In an order of mudstone, calcareous siltstone, and silty carbonate, rebound hardness and Young’s modulus show an increasing trend. As a result of rock-fluid interactions, there are potential scaling reactions during completion and production that could ultimately affect permeability and production rates. Overall, the proposed multiscale integration approach is critical for the geologic characterization of most rocks. However, in shale reservoirs dominated by microporosity and microstructure where engineered fractures are expected to provide permeability at a reservoir scale, successful integration is essential. An optimized, integrated geological characterization of the Caney Shale that is well aligned with the engineering designs in drilling, completing, and producing wellbores will ultimately lead to optimal production while providing safe and environmentally responsible operations.

Rock Properties versus Blades and Grit Consumption in Granite Multi Blade Sawing Process

2013 ◽  
Vol 548 ◽  
pp. 115-123
Author(s):  
Hieres Vettorazzi da Silva ◽  
Nuria F. Castro ◽  
Rosana Elisa Coppedê
Keyword(s):  
Standardized Testing ◽  
Great Influence ◽  
Rock Properties ◽  
Petrographic Analysis ◽  
Reference Equipment ◽  
Rock Types ◽  
Steel Shot ◽  
Stone Characteristics ◽  
Sawing Process ◽  
Cutting Mechanisms

Among the dimensional stone production processes, block splitting into slabs is very important in terms of time, costs and quality of final products. The world’s leading reference equipment for granite block cutting is the multi blade gang saw, in which sawing is the consequence of the combined action of a set of steel blades settled in an oscillating frame and an abrasive slurry containing water, steel shot and lime or bentonite. As the blades enter the block, stone powder is added to the abrasive slurry and as commercial granites include very different rock types, slurry characteristics also depend on the rock nature. Consequently, parameters of the cutting process have great variability. Depending on those parameters, the steel blades and shot are worn out differently during this process having great influence on costs. Due to its complexity, stone cutting mechanisms are still not well understood but compression, abrasion, impact and stone characteristics seem to influence the most. Aiming to help with the understanding of that process and based on previous studies, this work intends to establish correlations between granite petrographic and technological characteristics and steel blades and shot consumption. Laboratorial studies that include petrographic analysis, physical indexes measurement, and abrasion, impact and compression standardized testing of a selected group of stones are being crossed over with steel blades and steel shot consumption measurements in gang saws from several Brazilian processing companies. Although it is a study in progress, preliminary results show a relationship between the characteristics of selected stones and steel blades and shot consumption within the sawing process. The higher the quartz contents of the rock the higher its abrasion resistance, which results in higher consumption of steel shot during sawing. It can be also pointed out that beyond quartz and k-feldspar contents, microfissures seem to have influence on compression strength of the stones and this strength is directly related to the steel blades consumption. This can allow not only a better understanding of slabs production in multi blade gang saws process, but also to improve that process control.

Mixing of basaltic and andesitic magmas in the Bazman volcanic field of southeastern Iran as inferred from plagioclase zoning

2017 ◽  
Vol 81 (4) ◽  
pp. 975-985 ◽  
Author(s):  
Zahra Firouzkouhi ◽  
Ali Ahmadi ◽  
David Richard Lentz ◽  
Ali-Asghar Moridi-Farimani
Keyword(s):  
Basaltic Magma ◽  
Volcanic Field ◽  
Common Type ◽  
Oscillatory Zoning ◽  
Plagioclase Feldspar ◽  
The Core ◽  
Rock Types ◽  
Anorthite Content ◽  
Plagioclase Zoning ◽  
Compositional Zonation

AbstractLate Cenozoic basalts of the Bazman volcanic field, Makran volcanic arc of southern Iran, contain two types of plagioclase feldspar phenocrysts with significant textural and compositional differences. The most common type is rather homogeneous with only weak zoning and maximum An content of 83 mol.%. The less common type of phenocryst exhibits complex zoning and, other than rims, is close in composition and similar in texture to those of associated andesites. This type of plagioclase phenocryst is characterized by an engulfed core with oscillatory zoning, which is overgrown by sieve-textured, moderately zoned mantle, and a relatively narrow rim. In both rock types, the An content of the core is between 40 and 63 mol.% with abrupt fluctuations. No significant correlation between An content and MgO, FeO, SrO and BaO is apparent in the core of phenocrysts in basalts. Anorthite content of the core of phenocrysts in andesites inversely correlates with SrO and BaO. The mantle of plagioclase phenocrysts in both rock types is characterized by sharp increases of An (up to 41 mol.%), MgO, and FeO, in the contact with the core. Anorthite correlates positively with MgO and FeO in the mantle, but correlation between An and SrO and BaO is not evident. It is assumed that plagioclase phenocrysts originally crystallizing from the host andesitic magma were interrupted by mixing with a hotter, juvenile basaltic magma. The resulting changes in temperature, composition, and H2O content of the surrounding melt caused compositional zonation, and the development of resorption in the cores and sieve texture in the mantles. As the An contents of the rims of the phenocrysts resemble the average An content of the groundmass plagioclases in both rock types, it is thought that the two involved magmas gained their independent physical identity before the formation of compositionally-distinct rims of plagioclase phenocrysts.

Development of Electrical Porcelain Glazes from Non-Essential Materials in Ghana Using RO/R2O, R2O3, RO2 Classification

2011 ◽  
Vol 5 ◽  
pp. 74-83
Author(s):  
P.S. Kwawukume ◽  
Albert Essuman ◽  
Robert Amoanyi
Keyword(s):  
Molecular Weight ◽  
Iron Oxide ◽  
Physical Examination ◽  
Electrical Porcelain ◽  
Chemical Analyses ◽  
Silicate Minerals ◽  
Molecular Weights ◽  
Brown Colour ◽  
Porcelain Glaze ◽  
The Right

The use of non-essential materials in Ghana like granites, cocoa pod ash and shells as fluxes has been studied in the composition of a local brown glaze in the Na2O-K2O-CaO-Al2O3-SiO2 systems to support electrical porcelain glaze development which hitherto relied totally on imported glazes. Chemical analyses have been performed on the various materials and revealed the presence of the right quantities of aluminous-silicate minerals necessary for combinations in glaze development using the Segar classification. It was found that the range of 0.2 - 0.4 molecular weight of the granites, 0.1 - 0.3 for the cocoa pod ash and 0.4 - 0.8 for the shells forming the R2O/RO2 group and the ratio of 1:12 for the clay and the sand was sufficient to cause excellent melt at 1200OC when 5% - 8% of local manganese and 5% local iron oxide were added to the recipe. The molecular weights of the various oxides in the R2O group were calculated from the chemical analyses of the various materials to reflect the right quantities of the oxides. The results also indicate that holding the RO/R2O group within the above limits and varying the clay to sand ratio from1:8 - 1:12, other glaze melting surfaces from matt to gloss are achievable. Physical examination of the melted glaze on the electrical porcelain bodies showed consistent rich brown colour, well vitrified with no crazing, peeling or pin holes, at pottery temperatures of 1140 - 12000C.

scholarly journals Pyrometamorphic Rocks in the Molinicos Basin (Betic Cordillera, SE Spain): Insights into the Generation of Cordierite Paralavas

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 748 ◽  
Author(s):  
Isabel Abad ◽  
Mario Sánchez-Gómez ◽  
Matías Reolid ◽  
Vicente López Sánchez-Vizcaíno
Keyword(s):  
Combustion Process ◽  
Thermal Anomaly ◽  
Betic Cordillera ◽  
Compositional Variation ◽  
Equilibrium Conditions ◽  
Se Spain ◽  
Rock Types ◽  
Depositional System ◽  
Clay Layers ◽  
The Right

A singular thermal anomaly occurred in the Molinicos Miocene, lacustrine, intramontane basin (Betic Cordillera). This gave place to vitreous vesicular materials (paralavas) and baked rocks (clinker) inside of a sequence of marly diatomites and limestones. The chemical composition of the paralavas (SiO2 = 52–57, Al2O3 ≈ 20, Fe2O3 = 10–20, K2O + Na2O < 2.5, CaO < 4.5, and MgO < 1.5, % in weight), which is very different from typical igneous rocks, and their high-T mineralogy (cordierite, sillimanite, anorthite, mullite, and high-T silica polymorphs) suggest that they formed during a pyrometamorphic event. The occurrence of dry intervals in the lacustrine depositional system, the high Total Organic Carbon contents (>4% in weight) of dark clay layers and the existence of tectonic fractures give the right context for a combustion process. Short-term heating favoured the generation of paralavas, clinker and marbles. Thermodynamic modelling constrains the onset of melting at 870–920 °C for <10 MPa at equilibrium conditions. However, the presence of tridymite and/or cristobalite in clinker and paralavas and the compositional variation in both rock types suggests that the temperature at which first melting occurred ranged between 870 °C and 1260 °C due to melt fractionation processes.

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