scholarly journals QUANTITATIVE ANALYSIS OF ASBESTOS FIBRES IN OPHIOLITIC ROCKS USED AS AGGREGATES AND HAZARD RISK ASSESSMENT FOR HUMAN HEALTH

2017 ◽  
Vol 43 (5) ◽  
pp. 2712 ◽  
Author(s):  
I. Rigopoulos ◽  
B. Tsikoura ◽  
P. Pomonis ◽  
S. Karipi ◽  
K. Hatzipanagiotou
Keyword(s):  
Petrographic Analysis ◽  
Scattered Electron ◽  
Northern Greece ◽  
Thin Sections ◽  
Preliminary Identification ◽  
Polarized Microscopy ◽  
Fibrous Minerals ◽  
Ophiolitic Rocks ◽  
Asbestiform Minerals ◽  
Fibrous Mineral

This study focuses on the quantification of asbestiform minerals in basic and ultrabasic rocks from ophiolite suites of central and northern Greece. A combination of different methods were used for the detailed investigation of the samples, conducted in the following stages: (i) petrographic examination of thin sections with a polarizing microscope, (ii) mineral phase analysis using X-ray diffraction, (iii) determination of the fibrous mineral composition on polished thin sections using scanning electron microscopy, (iv) image analysis of back scattered electron images and secondary electron images, to quantify the dangerous asbestiform crystals. SEM is proved to be the most powerful tool for the detailed investigation of fibrous minerals, although polarized microscopy and XRD are necessary tools for a preliminary identification of these minerals. Basic rocks contain various amounts of actinolite, however not all crystals comprise asbestiform fibres. A conspicuous feature observed during careful petrographic analysis is that many of the non as best form actinolite crystals are broken up along their cleavage planes. Rocks with such features need specific consideration since these crystals may subsequently release numerous fibrous cleavage fragments during the production processes and in-service deterioration of aggregates. Among the serpentinized ultrabasic samples, only one contains chrysotile, while the other samples contain antigorite and lizardite.

scholarly journals Mineralogical and Microstructure Analysis for Characterization and Provenance of Ceramic Artifacts from Late Helladic Kastrouli Settlement, Delphi (Central Greece)

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Vayia Xanthopoulou ◽  
Ioannis Iliopoulos ◽  
Ioannis Liritzis
Keyword(s):  
Raw Materials ◽  
Analytical Techniques ◽  
Sem Analysis ◽  
Petrographic Analysis ◽  
Ceramic Assemblage ◽  
Thin Sections ◽  
Central Greece ◽  
High Calcium ◽  
Local Geology

The present study deals with the characterization of a ceramic assemblage from the Late Mycenaean (Late Helladic III) settlement of Kastrouli, at Desfina near Delphi, Central Greece using various analytical techniques. Kastrouli is located in a strategic position supervising the Mesokampos plateau and the entire peninsula and is related to other nearby coeval settlements. In total 40 ceramic sherds and 8 clay raw materials were analyzed through mineralogical, petrographic and microstructural techniques. Experimental briquettes (DS) made from clayey raw materials collected in the vicinity of Kastrouli, were fired under temperatures (900 and 1050 °C) in oxidizing conditions for comparison with the ancient ceramics. The petrographic analysis performed on thin sections prepared from the sherds has permitted the identification of six main fabric groups and a couple of loners. The aplastic inclusions recognized in all fabric groups but one confirmed the local provenance since they are related to the local geology. Fresh fractures of representative sherds were further examined under a scanning electron microscope (SEM/EDS) helping us to classify them into calcareous (CaO > 6%) and non-calcareous (CaO < 6%) samples (low and high calcium was noted in earlier pXRF data). Here, the ceramic sherds with broad calcium separation are explored on a one-to-one comparison on the basis of detailed mineralogical microstructure. Moreover, their microstructure was studied, aiming to estimate their vitrification stage. The mineralogy of all studied samples was determined by means of X-ray powder diffraction (XRPD), permitting us to test the validity of the firing temperatures revealed by the SEM analysis. The results obtained through the various analytical techniques employed are jointly assessed in order to reveal potters’ technological choices.

Mineralogical characterization of fibrous zeolites from the Kahrizak volcanic suite, south Tehran, Iran

Clay Minerals ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 507-517 ◽  
Author(s):  
M. Kusehlar ◽  
F. Tutti ◽  
H. Mirnejad ◽  
A. E. Lalonde
Keyword(s):  
Volcanic Rocks ◽  
Hydrothermal Activity ◽  
Scattered Electron ◽  
Northern Iran ◽  
Mineralogical Characterization ◽  
Thin Sections ◽  
Rich Solution ◽  
Cavity Filling ◽  
Fibrous Zeolites

AbstractSelected samples of large cavity filling and vein-type fibrous zeolites from Eocene volcanic rocks in the Kahrizak region, northern Iran, have been studied for their mineralogical and chemical characteristics. X-ray powder diffraction and electron microprobe analyses confirmed the presence of natrolite, mesolite and scolecite with compositions of [Na14.922Ca0.202K0.015Ba0.002] [Al15.697Si24.267O80]·nH2O, [Ca15.714Na14.224][Al46.431Si73.398O240]·nH2O and [Ca7.804Na0.142K0.024Ba0.012Mg0.006][Al15.320Si24.437O80]·nH2O, respectively. In addition, examination of textural relationships in thin sections and back-scattered electron images reveals a paragenetic order in which the Ca-rich zeolites crystallized first. It is most probable that the fibrous zeolites of Kahrizak were formed during two pulses of hydrothermal activity in the area. Scolecite and mesolite were precipitated from Ca-rich solution, whereas the second stage Na-rich, low-temperature fluid crystallized natrolite and reacted with Ca-species.

scholarly journals Lithostratigraphy and microfacies analysis of Avanah Formation (Middle Eocene) in Gomaspan section northeast Erbil City, Kurdistan region, Iraq

2021 ◽  
Author(s):  
Irfan Sh. Asaad ◽  
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
Petrographic Analysis ◽  
Microfacies Analysis ◽  
Dolomitic Limestone ◽  
Kurdistan Region ◽  
Thin Sections ◽  
Lithostratigraphic Units ◽  
Lagoon Environment

Lithostratigraphy and microfacies analysis of the Avanah Formation (Middle Eocene) were studied in the Gomaspan section in the Bina Bawi anticline, northeast of Erbil city, Kurdistan Region, Iraq. The field observations refer that the formation attains 56 m of medium to thick bedded yellow limestone, grey dolomitic limestone and blue marly dolomitic limestone interbedded with thin beds of blue marl and dark grey shale with an interval of sandy limestone in the middle part and thin to medium bedded limestone interbedded with red mudstone. The petrographic study of 29 thin sections of Avanah carbonates revealed that the majority of the matrix is carbonate mud (micrite) with few microspar. The skeletal grains include benthic foraminifera, dasycladacean green algae, ostracods, calcispheres, pelecypods, rare planktonic foraminifera and bryozoa in addition to bioclasts. Non-skeletal grains encompass peloids, oncoids, intraclasts and extraclasts with common monocrystalline quartz. Based on the field observation and petrographic analysis, three different lithostratigraphic units were identified. They are in ascending order: A-Thick bedded dolomitic marly limestone interbedded with shale. B- Bedded dolomitic limestone interbedded with shale and marl. C- Thin to medium bedded limestone interbedded with red mudstone. Depending on detailed microfacies analysis of carbonate rocks, three main microfacies and 12 submicrofacies are recognized. From the sum of all petrographic, facies, textural analyses, it is concluded that Avanah Formation in Gomaspan section, was deposited in shallow marine environment, semi restricted lagoon, in lower and upper parts and open lagoon environment in the middle part interval.

scholarly journals Micro-Raman Spectroscopy, a Powerful Technique Allowing Sure Identification and Complete Characterization of Asbestiform Minerals

2019 ◽  
Vol 9 (15) ◽  
pp. 3092 ◽  
Author(s):  
Caterina Rinaudo ◽  
Alessandro Croce
Keyword(s):  
Raman Spectroscopy ◽  
Crystal Surface ◽  
Complete Characterization ◽  
Mineral Phase ◽  
Asbestos Fibers ◽  
Micro Raman Spectroscopy ◽  
Fibrous Minerals ◽  
Iron Sulphate ◽  
Asbestiform Minerals

Micro-Raman spectroscopy has been applied to fibrous minerals regulated as “asbestos”—anthophyllite, actinolite, amosite, crocidolite, tremolite, and chrysotile—responsible of severe diseases affecting mainly, but not only, the respiratory system. The technique proved to be powerful in the identification of the mineral phase and in the recognition of particles of carbonaceous materials (CMs) lying on the “asbestos” fibers surface. Also, erionite, a zeolite mineral, from different outcrops has been analyzed. To erionite has been ascribed the peak of mesothelioma noticed in Cappadocia (Turkey) during the 1970s. On the fibers, micro-Raman spectroscopy allowed to recognize many grains, micrometric in size, of iron oxy-hydroxides or potassium iron sulphate, in erionite from Oregon, or particles of CMs, in erionite from North Dakota, lying on the crystal surface. Raman spectroscopy appears therefore to be the technique allowing, without preparation of the sample, a complete characterization of the minerals and of the associated phases.

Borehole image electrofacies with a comparative carbonate petrography analysis: An outcrop well study associated with reservoir application in the Ordovician Tarim Basin

2018 ◽  
Vol 6 (3) ◽  
pp. T723-T737
Author(s):  
Tao Nian ◽  
Zaixing Jiang ◽  
Hongyu Song
Keyword(s):  
Diagnostic Criteria ◽  
Carbonate Platform ◽  
Image Interpretation ◽  
Image Data ◽  
Depth Interval ◽  
Petrographic Analysis ◽  
Thin Sections ◽  
Direct Interpretation ◽  
Borehole Image ◽  
Subsurface Reservoir

Electrical borehole image logs have the potential for direct interpretation of lithofacies characteristics. The challenge is to establish a set of reliable diagnostic criteria with which electrical images can be correlated to lithofacies features such as lithology, sedimentary structures, and bedding sequences. We used the “behind-outcrop” logging procedure that can link borehole images to actual rocks and also reduce errors that are associated with core-shift process. To better reveal the correlation between borehole images and carbonate lithofacies for subsurface reservoir applications, and also make a comparative petrographic analysis with the aim of establishing diagnostic criteria for borehole images, a 200 m well was drilled in the Tarim Ordovician outcrop. A full set of borehole image data and cores with approximately 100% coring recovery rate was acquired at the same depth interval, and more than 100 stained thin sections were prepared. Electrical borehole images in wells adjacent to the outcrop were further interpreted to validate the proposed criteria. Borehole image electrofacies were established according to the image elements, such as stacked mode, bed thickness, conglomerate diameter, rim characteristics, and internal structure of bed/conglomerate, to interpret depositional/diagenetic textures and platform-slope associations. Nine image electrofacies types, corresponding to mud/wacke/pack/grain/bindstone texture, were identified and interpreted in detail. Our method reveals a set of diagnostic criteria for borehole image interpretation in carbonate platform slope, and it finally provides a powerful tool for direct interpretation of electrical images in similar reservoir environment.

Formation of wide-blocky calcite veins by extreme growth competition

2020 ◽  
pp. jgs2020-104
Author(s):  
Liene Spruženiece ◽  
Michael Späth ◽  
Janos L. Urai ◽  
Estibalitz Ukar ◽  
Michael Selzer ◽  
...  
Keyword(s):  
High Resolution ◽  
Growth Rates ◽  
Polarized Light ◽  
Wall Rock ◽  
Scattered Electron ◽  
Thin Sections ◽  
Content Type ◽  
Calcite Veins ◽  
Supplementary Material ◽  
Electron Back Scattered Diffraction

Liassic limestones on the coast of Somerset in the UK contain dense arrays of calcite microveins with a common, but poorly understood microstructure, characterized by laterally wide crystals that form bridges across the vein. We investigated the mechanisms of formation and evolution of these ‘wide-blocky’ vein microstructures using a combination of high-resolution analytical methods, including virtual petrography, optical cathodoluminescence and scanning electron microscopy techniques (e.g. energy-dispersive X-ray spectrometry, back-scattered electron imaging, cathodoluminescence and electron back-scattered diffraction), laboratory experiments and multiphase field modelling. Our results indicate that the studied veins formed in open, fluid-filled fractures, each in a single opening and sealing episode. As shown by the optical and electron back-scattered diffraction images, the vein crystals grew epitaxially on grains of the wall rock and we hypothesize that their growth rates differed depending on whether the crystals were on a wall rock grain substrate that fractured intergranularly (slow growth rates) or transgranularly (rapid growth rates). Our multiphase field models support this hypothesis, showing that wide, blocky crystals only form where there are significant differences in the growth rate and are dependent on the type of seed grain. These results provide strong evidence for extreme growth competition, a process that we propose controls vein-filling in many micritic carbonate reservoirs, as well as demonstrate that the characteristics of the fracture wall can affect the filling processes in syntaxial veins.Supplementary material: The description and images of the studied thin sections are available at https://doi.org/10.6084/m9.figshare.c.5172371. High-resolution optical microscopy mosaics (under plane-polarized- and crossed polarized light) of the thin section collection in PetroScan file format are available on request from the authors.

An SEM study of phyllosilicate diagenesis in sandstones and mudstones in the Westphalian Coal Measures using back-scattered electron microscopy

Clay Minerals ◽  
1986 ◽  
Vol 21 (4) ◽  
pp. 603-616 ◽  
Author(s):  
J. M. Huggett
Keyword(s):  
Electron Microscopy ◽  
Scattered Electron ◽  
Thin Sections ◽  
Fine Grained ◽  
South Wales ◽  
East Midlands ◽  
Sem Study ◽  
Hercynian Orogeny ◽  
Electron Imaging ◽  
Coal Measures

AbstractBack-scattered electron imaging was used in conjunction with energy-dispersive spectral analysis to study phyllosilicate minerals in polished thin-sections of Carboniferous (Westphalian) sandstones and associated mudstones from the East Midlands and from the diagenetically higher grade area of Abernant in the South Wales coalfield. Chemical diagenesis proceeded more rapidly in the sandstones than in the mudstones. In the East Midlands, greater flow of freshwater through the sandstones than the mudstones produced a higher degree of alteration of muscovite to kaolinite in the sandstones. Chlorite is present in the Well 1 and Well 2 East Midlands sandstones but not the mudstones nor any Well 3 samples. The chlorite may be an early diagenetic replacement of biotite. Much chlorite has been replaced by kaolinite. In the Abernant samples chlorite is present in both the sandstones and mudstones. In the former it appears to have replaced detrital biotite. In the latter the chlorite is too fine-grained to discern whether it is detrital or authigenic. The chlorite may have formed during the Hercynian orogeny. Much of the mica and chlorite in the Abernant sandstones has been replaced by illite, possibly in the post-orogenic period. The scarcity of kaolinite in the Abernant samples reflects the lack of freshwater leaching.

An Archaeometric Characterization of Ancient Pottery from Huagangshan Site, Eastern Taiwan

2020 ◽  
Author(s):  
Ying San Liou
Keyword(s):  
Amorphous Carbon ◽  
Firing Temperature ◽  
Raw Materials ◽  
River Sediments ◽  
Archaeological Site ◽  
Point Of View ◽  
Petrographic Analysis ◽  
Main Stream ◽  
Thin Sections ◽  
Metal Age

&lt;p&gt;Micro-Raman spectroscopy and petrographic analysis was carried out on ancient potsherds and sediments excavated from the Huagangshan site and river sediments collected from the northern part of eastern Taiwan. The ceramic fragments analyzed, dating back to 1600-2100 B.P., are recognized to be Early Metal Age of Taiwan. The aims of this study are mainly to identify the mineralogical compositions of ceramics, to explore technical processes such as firing temperature and redox state, and to decipher the nature of clays and its raw materials source.&lt;/p&gt;&lt;p&gt;The results of micro-Raman analysis for ancient potsherds show the presence of 12 minerals. Quartz, anatase, amorphous carbon, hematite, and pyroxenes are the main components of tempers. In addition, amorphous carbon and hematite are the main constitutes for black- and red- hues pottery, respectively. From the point of view of manufacturing techniques, a large amount of amorphous amorphous carbon indicates that the gray-black pottery is fired under a reducing condition. On the contrary, hematite reveals an oxidizing atmosphere for red-hues pottery. The presence of quartz and anatase implies that the firing temperature is estimated to be 750-950&amp;#176;C. A total of 66 samples, containing 23 ceramic fragments (local and imported products) and 6 sediment from cultural strata of archaeological site and 33 river sediments around the site, is implemented by petrographic analysis of thin sections. Petrographic analytic results of 23 potshards show that the proportion of clay is consistent (60.5~69.1%). The inclusions principally include quartz (polycrystalline and monocrystalline quartz), feldspar, muscovite, and volcanic, sedimentary and metamorphic lithic fragments, and quartz is the main component. In addition, the triangle map with ingredients (volcanic lithics+quartz&amp;#65293;sedimentary lithics&amp;#65293;metamorphic lithics) shows that the raw materials source of local and main stream pottery recognized by archaeologist is not local, but comes from a distance area (the Coastal Range). On the other hand, imported pottery indicates the raw materials source is indeed from the central and southern Central Range (some distance south of the site). The result further illustrates the vigorous exchange and/or trade activities between the populations of eastern Taiwan during the Early Metal Age (1600-2100 B.P.).&lt;/p&gt;

Surface treatment of Neolithic vessels from Macedonia and Thrace

2001 ◽  
Vol 96 ◽  
pp. 1-25 ◽  
Author(s):  
Paraskevi Yiouni
Keyword(s):  
Surface Treatment ◽  
Microscopic Examination ◽  
Petrographic Analysis ◽  
Northern Greece ◽  
Large Sample ◽  
Firing Techniques ◽  
Materials Used ◽  
First Time

This article examines the methods of surface treatment of the Neolithic vessels from northern Greece. The work is based on the study of a large sample of ceramics, covering the whole span of the Neolithic, from Macedonia and Thrace. Macroscopic study of the material was complemented by microscopic examination (SEM and petrographic analysis) and retiring tests. The results are compared with data from other technological analyses of Neolithic vessels from northern Greece. Apart from identifying, in some cases for the first time, methods of surface treatment and materials used by the potters of these regions, the present study considers the changes in surface treatment and firing techniques through time.

scholarly journals The Petrographic Analysis of Sherds from the Musgano Site (41RK19), Rusk County, Texas

2014 ◽  
Author(s):  
Steve A. Tomka ◽  
Lori B. Love ◽  
Timothy K. Perttula
Keyword(s):  
Mineralogical Composition ◽  
Petrographic Analysis ◽  
Long Distance ◽  
Thin Sections ◽  
Research Issues ◽  
Economic Relationships ◽  
University Of Texas ◽  
Ceramic Vessels ◽  
Ceramic Manufacturing ◽  
Trade And Exchange

Characterizing the mineralogical composition of ceramic vessels and sherds from Caddo sites in East Texas by means of petrographic analysis provides a unique opportunity to gather and investigate empirical evidence from ceramic vessels on: (1) technological and manufacturing practices, and (2) their trade and exchange at varying scales conducted by ancestral Caddo people with their neighbors, both near and far (i.e., other ancestral Caddo groups as well as non-Caddo communities). This evidence in turn can be used to explore changes in the nature of social and economic relationships between particular Caddo groups and other prehistoric populations. Identified compositional and paste differences that have been recognized between the different wares made by Caddo groups (i.e., plain wares, utility wares, and fine wares) can also be employed to explore functional and technological differences in vessel function and form. It is important to build on existing petrographic studies of Caddo vessels and vessel sherds by examining unstudied assemblages to (1) better clarify the compositional nature of these ceramic wares across the Caddo temporal and geographic landscape; (2) to help pinpoint other ceramic manufacturing locales and mineralogical compositional groups, but also to assess their apparent technological complexity; and (3) lead to better evaluations of the regional character of prehistoric and historic Caddo trade and interaction networks that existed, and more definitively establish whether there were changes through time in the direction and intensity of local and long distance trade and interaction. The disparate pieces of information contained within the sherds and vessel fragments of Caddo ceramics found on many prehistoric and early historic sites throughout the region have the potential to address these questions and research issues, and can contribute unique information concerning those relationships that existed in the distant (and not-so-distant) past between Caddo farmers. Twenty decorated sherds from the Musgano ceramic assemblage curated at the Texas Archeological Research Laboratory at The University of Texas at Austin (TARL) were selected for petrographic analysis. The sherds were split and one of the remaining fragments of each pair was used for the production of thin sections. Originally, the other half of each sherd was to be submitted for instrumental neutron activation analysis, but such analyses were not done; the remaining sherd fragment was returned for continued curation at TARL. Upon the receipt of the thin sections, they underwent petrographic analysis as reported on herein. The 20 sherds include sherds from engraved fine wares (n=8, 40 percent)—bottles and carinated bowls— as well as sherds from utility wares (n=12, 60 percent). The utility wares have brushed-appliqued, incised, incised-punctated (from Maydelle Incised, Weches Fingernail Impressed, and Washington Square Paneled vessels), and punctated decorative elements. Ten percent of the sherds are from bone-tempered vessels, based on macroscopic examination, while the others are from grog-tempered vessels.

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