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Mineralogical Analyses (mineralogical + analysis)
Selected AbstractsCHEMICAL,MINERALOGICAL ANALYSES AND MICROSTRUCTURAL STUDIES OF PREHISTORIC POTTERY FROM RAHMATABAD, SOUTH-WEST IRAN*ARCHAEOMETRY, Issue 5 2009A. K. MARGHUSSIAN A series of prehistoric pottery samples excavated from Rahmatabad, south-west Iran, were investigated using XRF and XRD analyses to determine their chemical and mineralogical compositions. The sample microstructures were also studied by SEM/EDX. The relative similarity of compositions, the fine, dense and homogeneous microstructures and the presence of high-temperature phases such as diopside and mullite showed the use of high firing temperatures, in the range 950,1050°C. This, along with the homogeneity in shape, decoration and size ranges of the ware, all indicate the adoption of specialized pottery-making techniques by the potters of Rahmatabad in the fifth to fourth millennia bc. [source] Epidemiology of canine urolithiasis in the Czech Republic from 1997 to 2002JOURNAL OF SMALL ANIMAL PRACTICE, Issue 4 2005M. Sosnar Objectives: To compare data on the epidemiology of canine urolithiasis in the Czech Republic with that from other countries. Methods: The records from the Centre for Mineralogical Analysis from 1997 to 2002 were reviewed. The data were obtained from mineralogical analysis of 1366 canine uroliths obtained from patients in the Czech Republic. These included 396 females and 629 males. Results: Sixty-eight breeds plus crossbreeds were identified. Eight breeds plus the crossbreeds accounted for 71.3 per cent of all cases. Males were affected more frequently than females (61.4 per cent versus 38.6 per cent). Struvites significantly predominated in females, while in males calcium oxalates, brushites and cystines were the most common stones. Most of the uroliths (48.9 per cent) were 5 mm or less in dimension. By 2001, struvite was the most frequent (38.5 to 44.1 per cent) urolith, followed by calcium oxalate (26.5 to 32.0 per cent). In 2002, calcium oxalate became the most frequent calculus, followed by struvite, mixed calculi and others. Clinical Significance: Comparison of these results with studies by other authors showed that for most of the monitored parameters there was agreement with respect to the proportions of different breeds within the populations of dogs in different geographical areas. [source] Separation and Mineralogical Analysis of Bayer Red MudASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5-6 2002T. Picaro This paper describes preliminary work to assess the potential for recovering valuable components from Queensland Alumina Limited (QAL) red mud by physical beneficiation. Upgrading of Weipa bauxites residue was trialed using a 50 mm hydrocyclone and a Mozley Multigravity Separator (MGS) to recover desilication product (DSP) and TiO2 fractions. The mineralogy of the original red muh and the various sub-fractions produced was studied by chemical assay, selective leaching, XRD and SEM techniques. DSP is present in QAL red mud in two forms: (i) as balls in the size range from 0.8 to 10 ,m that appear to be liberated; and (ii) as finely grained DSP intermixed with the other minerals. The hydrocycloning tests produced a DSP rich (39.5 wt%) fraction at 89% recovery from a feed containing 31.9 wt.% DSP. This represents an upgrade (enrichment) of 1.24 times. These results suggest that the greatest DSP enrichment will be achieved by targeting the 0.8 to 10 ,m DSP balls. The richest TiO2 fraction produced varied from 20 to 36 wt.% TiO2 from a feed value of 7 wt.% at a recovery of 7.5%. Mineralogical examination showed that most of the TiO2 in this fraction was as liberated particles in the size range 8 to 20 ,m. Most of the TiO2 particles in the other fractions were not fully liberated from mainly iron minerals. The present work indicates that it is possible to further upgrade DSP fractions by investigating finer particle separation techniques, e.g. smaller, 25 mm and 10 mm, hydrocyclones. [source] Temporal and spatial variability of cation and silica export in an alpine watershed, Emerald Lake, CaliforniaHYDROLOGICAL PROCESSES, Issue 10 2004T. Meixner Abstract A reaction set of possible mineral weathering reactions is proposed to explain observed cation and silica export for the Emerald Lake watershed, a small Sierra Nevada, California catchment. The reaction set was calculated through a stoichiometric mole-balance method, using a multiyear record of stream flow and snowpack chemical analyses and site-specific mineral compositions. Reaction-set calculations were intended to explore how the processes controlling stream cation and silica export depend on differing bedrock mineralogy across the catchment as snowmelt and runoff patterns change over the year. Different regions within the watershed can be differentiated by lake inflow subdrainages, each exhibiting different stream-flow chemistry and calculated weathering stoichiometry, indicating that different silica and cation generation processes are dominant in wet steep portions of the catchment. Short-term differences in stream concentrations were assumed to reflect ion exchange equilibria and rapid biological processes, whereas long-term persistent stream concentration differences in different areas of the catchment were assumed to reflect spatial variability in mineral weathering stoichiometry. Mineralogical analyses of rock samples from the watershed provided site-specific chemical compositions of major mineral species for reaction calculations. Reaction sets were evaluated by linear regression of calculated versus observed differences between snowmelt and stream-flow chemistry and by a combined measure. Initially, single weathering reactions were balanced and evaluated to determine the reactions that best explained observed stream chemical export. Next, reactions were combined, using mineral compositions from different rock types to estimate the dependence of ion fluxes on lithology. The seasonal variability of major solute calculated fluxes is low, approximately one order of magnitude, relative to the observed three orders of magnitude variability in basin discharge. Reaction sets using basin-averaged lithology and Aplite lithologies gave superior explanations of stream chemical composition. Copyright © 2004 John Wiley & Sons, Ltd. [source] The geochemical diversity of neogene clay deposits in Crete and its implications for provenance studies of Minoan pottery,ARCHAEOMETRY, Issue 3 2004A. Hein The determination of provenance probably forms the primary role of geochemical analyses in archaeological ceramic studies. In what has comprised a successful field of study, the ultimate basis for such research has been the comparison of pottery compositions with the geochemical diversity displayed by clay deposits within a given study area. Although such studies are now common, the understanding of chemical and mineralogical variability in ceramic raw materials has been somewhat neglected, with the dominance of assumptions rather than the actual analysis of clays. In this paper, a study is presented of Neogene clays in Crete (Greece), a clay type commonly used in ancient and modern pottery production. Sixty-one samples were taken from 28 locations in the central and eastern parts of the island, to reveal both intra- and inter-deposit variability. In one deposit chosen for multiple sampling, the 14 samples display great variability in the alkali elements, Fe and Co, and to a lesser extent in the REEs. Many of the geographically separate deposits differ from each other in chemical composition, with Eastern Cretan deposits showing higher REE concentrations and higher Th/Sc ratios, whereas Central Cretan deposits of younger geological stages are characterized by a lower Th/U ratio. Mineralogical analysis by XRD is used to explain aspects of the geochemical variability of the clays. [source] ,Green earths': vibrational and elemental characterization of glauconites, celadonites and historical pigmentsJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2008Francesca Ospitali Abstract ,Green earths' are employed since antiquity as pigments in the creation of artworks. The minerals responsible for the colour belong to four groups: (1) the clayey micas celadonite and glauconite, undoubtedly the most common; (2) smectites; (3) chlorites; (4) serpentines. Whereas there have been several studies on clayey materials, mineralogical analyses in the field of cultural heritage are mainly limited to the identification of the green earth without specific characterization of the mineralogical species. This work shows a preliminary characterization by the multi-techniques approach of some raw minerals (glauconite, celadonite and ferroceladonite). Vibrational analyses have been correlated with elemental analyses, thanks to the hyphenated instrumentation of scanning electron microscopy with EDS and Raman structural and chemical analyser (SEM-EDS-SCA) probes, which permitted collection of EDS and Raman spectra on the same microscopic area. Micro-Raman and Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopies were able to distinguish between celadonite and glauconite. The use of different lasers revealed resonance effects in the Raman spectra. In addition to pure minerals, archaeological samples and commercial green earths were also analysed, thereby enabling a more precise classification of the green pigments in heterogeneous samples such as wall paintings. Some commercially available green earths were found to contain organic dyes. Copyright © 2008 John Wiley & Sons, Ltd. [source] LUSTRE-DECORATED CERAMICS FROM A 15TH TO 16TH CENTURY PRODUCTION IN SEVILLE*ARCHAEOMETRY, Issue 1 2010A. POLVORINOS DEL RIO A set of 17 fragments of ceramics have been uncovered on the occasion of excavations of a workshop in Triana near Seville. These ceramics are typical of objects that are not commonly encountered in present collections in spite of intensive production during the 15th,16th centuries. Chemical and mineralogical analyses have been performed using various techniques (X-ray fluorescence and diffraction, SEM, ion beam analyses). The majority of the ceramic sherds represent the diversity of the Seville production; three fragments recovered in the same archaeological context were not locally produced and belong to the production of eastern Spain (Valence area). The ceramic bodies of the Seville sherds are compatible with the use of clays from the Guadalquivir valley. The glaze and the lustre decoration are comparable to those produced in eastern Spain. These conclusions are based on data that represent the production of a single workshop in Seville; the scatter of the data is due to variations in the processing and/or to alterations during the five centuries of burial of the ceramic fragments. [source] A New Method for Clay Mineral Analysis and Its Application in GeologyACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2002WANG Hejing Abstract, X-ray diffraction (XRD) peaks in a low-angle diffraction section of clay minerals, especially those of authigenic origin, have broadening and tailing features in shape. Using the five basic parameters, peak position, peak height, width, shape coefficient and asymmetry, to describe an XRD peak is more accurate, comprehensive and integrated than using only 3 of them, position, height and width. Following the concept of the five basic parameters of an XRD peak, the program Decoform proposed in this study provides more information in mineralogical analyses by fitting actual XRD profiles. In combination with the HW-IR plot, Decoform can be systematically and accurately used in the comprehensive analyses of crystallinity, domain size, lattice strain and quantitative phase. It is also of value for the geological investigations of diagenesis, metamorphism, basin maturity, structural stress field and so on. [source] A preliminary archaeological and environmental study of pre-Columbian burial towers at Huachacalla, Bolivian AltiplanoGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 7 2002Matti J. Rossi Chullpas are pre-Columbian burial towers built by indigenous Aymaras on the Bolivian Altiplano. Bolivian chullpas date back to the Late Intermediate Period (A.D. 1000,1476) and the Late Horizon (A.D. 1476,1532). We recorded 228 chullpas among 84 sites in the Huachacalla region of west-central Bolivia. In our study area, the chullpas are on debris flows and coarse alluvium in the proximal and medial segments of alluvial fans at the foot of two volcanoes. Grain-size, element, and mineralogical analysis of chullpa wall material and local sediment revealed that the burial towers are composed of calcareous sand that is readily available in alluvial fan deposits near the sites. Our data suggest that the Aymaras considered environmental factors, such as drainage and stability of the soil, when they selected the locations of chullpas, whereas cultural factors played a significant role in chullpa architecture. © 2002 Wiley Periodicals, Inc. [source] Potential and Pitfalls in Establishing the Provenance of Earth-Related Samples in Forensic InvestigationsJOURNAL OF FORENSIC SCIENCES, Issue 4 2006Barry G. Rawlins Ph.D. ABSTRACT: Earth scientists are often asked to establish or constrain the likely provenance of very small quantities of earth-related material as part of a forensic investigation. We tested the independent and collective interpretations of four experts with differing analytical skills in the prediction of sample provenance for three samples from different environmental settings. The methods used were X-ray diffraction, scanning electron microscopy, the assessment of pollen assemblages, and structural characterization of organic matter at the molecular level. Independent interpretations were less accurate than those where multiple techniques were combined. Collective interpretation was very effective in the assessment of provenance for two of the three sites where the mineralogy and plant communities were distinctive. At the other site, although the mineralogical analysis correctly identified the Triassic mudstone soil parent material, Carboniferous spores from domestic coal were initially interpreted as deriving directly from bedrock. Such an interpretation could be a common pitfall owing to anthropogenic redistribution of material such as coal. [source] Epidemiology of canine urolithiasis in the Czech Republic from 1997 to 2002JOURNAL OF SMALL ANIMAL PRACTICE, Issue 4 2005M. Sosnar Objectives: To compare data on the epidemiology of canine urolithiasis in the Czech Republic with that from other countries. Methods: The records from the Centre for Mineralogical Analysis from 1997 to 2002 were reviewed. The data were obtained from mineralogical analysis of 1366 canine uroliths obtained from patients in the Czech Republic. These included 396 females and 629 males. Results: Sixty-eight breeds plus crossbreeds were identified. Eight breeds plus the crossbreeds accounted for 71.3 per cent of all cases. Males were affected more frequently than females (61.4 per cent versus 38.6 per cent). Struvites significantly predominated in females, while in males calcium oxalates, brushites and cystines were the most common stones. Most of the uroliths (48.9 per cent) were 5 mm or less in dimension. By 2001, struvite was the most frequent (38.5 to 44.1 per cent) urolith, followed by calcium oxalate (26.5 to 32.0 per cent). In 2002, calcium oxalate became the most frequent calculus, followed by struvite, mixed calculi and others. Clinical Significance: Comparison of these results with studies by other authors showed that for most of the monitored parameters there was agreement with respect to the proportions of different breeds within the populations of dogs in different geographical areas. [source] | |||||||||||||