Alteration Minerals in Granitic Rock at Ashio as Radionuclide Adsorption Materials

1994 ◽  
Vol 353 ◽  
Author(s):  
S. Hamasaki ◽  
K. Tsukimura ◽  
K. Fujimoto ◽  
K. Omura ◽  
R. Ikeda
Keyword(s):  
Host Rock ◽  
Mineral Assemblage ◽  
Granitic Rock ◽  
Drill Core ◽  
Radionuclide Transport ◽  
Central Japan ◽  
X Ray ◽  
Alteration Minerals ◽  
Analytical Scanning Electron Microscopy ◽  
Scanning Electron

AbstractAlteration minerals from a drill-core (maximum depth 2002 m) in the granitic rock at Ashio, central Japan, were studied by optical microscopy, X-ray diffractometry and analytical scanning electron microscopy. In the host rock, biotite is altered to chlorite and plagioclase to illite. Calcite has precipitated in veinlets and grain boundaries. The host rock close to fractures is strongly altered, whereas the rocks distant from fractures are less altered. Quartz, illite, chlorite, laumontite and calcite have precipitated on fracture walls. The alteration minerals are estimated to have formed in the range 140–200°C, higher than the present temperature (13°96°C). The chemical composition of the ground water in the granitic rock at Ashio was estimated thermodynamically from the mineral assemblage. The alteration reaction of palgioclase and the precipitation of calcite may occur simultaneously. The alteration minerals formed in the host rock and in the fractures may adsorb radionuclides effectively, and thus may inhibit radionuclide transport to biosphere.

scholarly journals EFFECTS OF IGNEOUS INTRUSION ON THE MINERALOGICAL CONTENT OF IRATI FORMATION, PARANÁ BASIN, IN SAPOPEMA (PR), SOUTHERN BRAZIL

2019 ◽  
Vol 4 (3) ◽  
pp. 350-360
Author(s):  
Werlem Holanda ◽  
Anderson Costa dos Santos ◽  
Camila Cardoso Nogueira ◽  
Luiz Carlos Bertolino ◽  
Sérgio Bergamaschi ◽  
...  
Keyword(s):  
Host Rock ◽  
Mineral Assemblage ◽  
Sedimentary Basins ◽  
Southern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineralogical Association ◽  
Irati Formation ◽  
Igneous Intrusions ◽  
Rock Association

Igneous intrusions in sedimentary basins are commonly related with mineralogical association changes in host-rock. At Sapopema region (Paraná State, southern Brazil), an extensive diabase sill (associated to Serra Geral Formation) was emplaced in pelitic-carbonate succession during post-Triassic. The sedimentary host-rock association includes mostly shale, siltstone and carbonate of the Permian Irati Formation. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) data revealed that heat transfer was not enough to cause modifications in mineral assemblage of the Taquaral Member (quartz + albite + muscovite + illite + kaolinite + chlorite). However, mineralogical content from Assistência Member presented changes probably caused by the intrusion of diabase sill (talc + pyrophyllite + calcite). Talc and calcite were formed due to the reaction between dolomite and quartz, while pyrophyllite was the product of reaction between kaolinite and quartz. EFEITOS DA INTRUSÃO IGNEA NA COMPOSIÇÃO MINERALÓGICA DA FORMAÇÃO IRATI, BACIA DO PARANÁ, SAPOPEMA (PR), SUL DO BRASIL ResumoAs intrusões ígneas em bacias sedimentares dão origem em geral a alterações mineralógicas da rocha hospedeira. Na região de Sapopema (Estado do Paraná, sul do Brasil), uma extensa soleira de diabásio (associada à Formação Serra Geral) pós-Triássica, foi intrudida numa sucessão sedimentar constituída por pelitos e carbonatos. A associação de rochas sedimentares hospedeiras, era principalmente constituída por folhelho, siltito e carbonato da Formação Irati, do Permiano. Dados de difração de raios X (DRX), microscopia eletrônica de varredura (MEV) e espectroscopia de energia dispersiva (EDS) revelaram que a transferência de calor não foi suficiente para causar modificações na composição mineralógica do membro Taquaral (quartzo + albita + moscovita + ilita + caulinita + clorita). No entanto, o conteúdo mineralógico do Membro Assistência apresentou alterações, provavelmente causadas pela intrusão do diabásio (talco + pirofilita + calcita). O talco e a calcita foram formados devido à reação entre dolomita e quartzo, enquanto a pirofilita foi o produto da reação entre a caulinita e o quartzo. Palavras-chave: Bacia Sedimentar. Intrusões Ígneas. Metamorfização de sedimentos. Reações mineralógicas. XRD. SEM / EDS.

Characteristics of halloysite associated with rectorite from Hubei, China

2006 ◽  
Vol 70 (3) ◽  
pp. 257-264 ◽  
Author(s):  
H.-L. Hong ◽  
J.-X. Mi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mineral Assemblage ◽  
Nanometer Scale ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Mineralogical Characteristics ◽  
Water Saturated ◽  
Scanning Electron

AbstractThe mineralogical characteristics of halloysite in rectorite pelite in the Zhongxiang area, Hubei, China, were investigated using X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy methods. The results show that halloysite crystals exhibit euhedral lamellar, tubular or club-like, and needle-like or fibre-like morphologies, indicating that they crystallized from a significantly water-saturated environment. The mineral assemblage of the rectorite pelite is rectorite, halloysite, illite, gypsum, pyrite and rutile, suggesting a weak supergene alteration. Several features related to crystallization of halloysite were noted. Growth of halloysite on rectorite edge surfaces in voids and twins of halloysite on a nanometer scale with composition plane (110) were found in the Zhongxiang rectorite pelite, and, in particular, the tapered ends of tubes suggest that halloysite crystallized from solution. Disaggregation of lamellar halloysite particles into parallel clusters of single tubular halloysite crystals suggests that because of significant [H2O] activity in the environment, halloysite may have been derived from the alteration of rectorite.

Pyrite micromorphology in three Australian Holocene sediments

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 637 ◽  
Author(s):  
Richard T. Bush ◽  
Leigh A. Sullivan
Keyword(s):  
Electron Microscopy ◽  
Sulfide Oxidation ◽  
Estuarine Sediments ◽  
X Ray Diffraction ◽  
Thin Coatings ◽  
X Ray ◽  
Holocene Sediments ◽  
Analytical Scanning Electron Microscopy ◽  
Scanning Electron

The distribution and morphology of pyrite in 3 Holocene estuarine sediments were examined using light microscopy, analytical scanning electron microscopy, and X-ray diffraction. The distribution and morphologies of pyrite were similar with pyrite being dispersed throughout the soil matrices as well as concentrated in root remnants and other macropores. The pyrite occurred in both framboidal and irregularly shaped dense clusters from 4 to 15 µm diameter, and also in loose clusters. Individual crystals in these clusters ranged in size from 1 to 2 µm. Pyrite crystals exhibited octahedral, pyritohedral, and equant anhedral (i.e. rounded globular) habit. Organic matter coatings and clay coatings were common around pyrite at each site. Thin coatings of monosulfide with an acicular morphology occurred around some framboidal clusters at one site. The distribution of framboids and individual crystals in the clayey matrix, root remnants, and other macropores indicates that the pyrite in these sediments has formed in situ. These data have important implications for the rate of sulfide oxidation and acid production from these soils.

scholarly journals Kaolinization processes in the phyolitic rocks of Kefalos, Kos island, Aegean Sea, Greece

2001 ◽  
Vol 34 (3) ◽  
pp. 867 ◽  
Author(s):  
D. PAPOULIS ◽  
P. TSOLIS - KATAGAS
Keyword(s):  
Electron Microscopy ◽  
Aegean Sea ◽  
Chemical Analyses ◽  
Bulk Rock ◽  
Secondary Mineral ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Assemblages ◽  
Analytical Scanning Electron Microscopy ◽  
Scanning Electron

Kaolin occurrences in the South Kefalos peninsula, Kos island, Aegean sea, Greece, are products of hydrothermal alteration of rocks of rhyolitic composition. The chemical, mineralogical and textural characteristics of kaolin occurrences were investigated by X-Ray diffraction (XRD), Analytical scanning electron microscopy (SEM) and bulk rock chemical analyses. Attempts have been made to correlate the primary with secondary mineral assemblages and to establish the factors controlling the stepwise character of the transition from the fresh rhyolitic to kaolinized rocks. The kaolinization processes follows two main alteration pathways: I) Kfeldspar —» Mixed-layer kaolinite-smectite —» kaolinite —> dickite. II) Na-plagioclase —> kaolinite —> dickite

Quantitative EDS analysis in the SEM applying the XPP procedure

1990 ◽  
Vol 48 (2) ◽  
pp. 194-195
Author(s):  
Jean-Louis Pouchou ◽  
Françoise Pichoir
Keyword(s):  
Light Elements ◽  
Absorption Coefficients ◽  
Experimental Conditions ◽  
X Ray ◽  
Eds Analysis ◽  
New Models ◽  
Quantitative Results ◽  
Analytical Scanning Electron Microscopy ◽  
Xpp Model ◽  
Scanning Electron

Extensive work has been done during the last decade to develop new models able to improve the performance of data reduction procedures 1n quantitative x-ray microanalysis. Some of them are now successfully used as routine tools in microprobe work, and allow to analyze accurately light and ultra-light elements and to characterize layered specimens.In the field of analytical scanning electron microscopy (SEM) using energy dispersive spectrometers (EDS), it seems that less attention has been paid to the effective improvement of the quantitation processes. Although EDS systems have unavoidable limitations due to their lower peak-to-background ratio and poorer resolution, the authors have the feeling that the quantitative results can be significantly improved by use of more reliable models taking properly into account the specific instrumental and experimental conditions.With this aim in view, our first contribution has been to implement our recently developed XPP model and associated routines (mass absorption coefficients, efficiency of the Quantum window) into the KEVEX Delta system.

Nanotube Formation on Ti-15Zr-4Nb-4Ta by Anodic Oxidation

2020 ◽  
Vol 985 ◽  
pp. 69-73
Author(s):  
Satoshi Okano ◽  
Masayuki Mori ◽  
Sengo Kobayashi ◽  
Takeaki Okamoto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ti Alloy ◽  
Applied Potential ◽  
X Ray ◽  
Vertically Aligned ◽  
Analytical Scanning Electron Microscopy ◽  
Inner Diameter ◽  
The Difference ◽  
Scanning Electron

Surface morphology and composition of anodized Ti-15Zr-4Nb-4Ta alloys with nanotube were examined by using X-ray diffractometry and analytical scanning electron microscopy. The Ti alloy consisted of α and β phases. Anodizing to form nanotube on the Ti alloy was carried out using electrolyte of 0.2 wt.% NH4F and 2 Vol.% H2O in ethylene glycol under different potential at from 30 to 60V. SEM observation showed that nanotubes were vertically aligned on surface of the Ti alloy. Inner diameter of these nanotubes varied from 45 to 127 nm with increasing applied potential to the specimen from 30 to 60 V. Surface of the Ti alloy with nanotube was ragged due to the difference in dissolution rate of the internal structure of α and β phases.

scholarly journals The Albitization of K-Feldspar in Organic- and Silt-Rich Fine-Grained Rocks of the Lower Cambrian Qiongzhusi Formation in the Southwestern Upper Yangtze Region, China

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 620 ◽  
Author(s):  
Min ◽  
Zhang ◽  
Li ◽  
Zhao ◽  
Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lower Cambrian ◽  
Mineral Assemblage ◽  
Sedimentary Rocks ◽  
Pore Filling ◽  
X Ray ◽  
Fine Grained ◽  
Diagenetic Processes ◽  
Rock Structure ◽  
Scanning Electron

The albitization of K-feldspar is a common diagenetic process that has thus far received little attention and is not fully understood in fine-grained sedimentary rocks. To better understand the albitization of K-feldspar, studies in organic- and silt-rich fine-grained rocks of the lower Cambrian Qiongzhusi Formation in the southwestern Upper Yangtze region, China, were carried out via X-ray diffractometry (XRD) and field emission scanning electron microscopy (FE-SEM). The results show that five types of albitized K-feldspar textures have developed: microcrystal albite replacement, irregular blocky replacement along margins, cleavage planes or microcracks of K-feldspars, complete pseudomorphic replacement, albite overgrowth, and albite pore filling. Organic- and silt-rich fine-grained rocks differ from sandstones and mudstones in terms of the rock structure and mineral assemblage, which results in differences in the textures and degree of albitization of K-feldspar. Illitization of clay has an impact on the albitization of K-feldspar. In provenance analyses using feldspar, fine-grained rocks, especially those that underwent mesogenesis, should be treated with caution because detrital feldspars have been destroyed. Theoretically, the albitization of K-feldspar could increase the porosity of reservoirs, although, from our observations, most of the related secondary pores are cancelled out or became isolated pores due to other diagenetic processes (compaction, cementation, etc.) in organic- and silt-rich fine-grained rocks.

Detection and Localization of Eu on Biosilica by Analytical Scanning Electron Microscopy

2021 ◽  
pp. 1-10
Author(s):  
Ellen Hieckmann ◽  
Kaitlin K. K. Kammerlander ◽  
Lydia Köhler ◽  
Laura Neumann ◽  
Stefan Saager ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Scattering ◽  
Contaminated Sites ◽  
Entire Surface ◽  
X Ray ◽  
Analytical Scanning Electron Microscopy ◽  
Thermogravimetric Studies ◽  
Detection And Localization ◽  
Scanning Electron ◽  
The Eu

Algae like diatoms are widely studied as a means to remediate anthropogenically contaminated sites. In the present study, CL (cathodoluminescence) and EDX (energy-dispersive X-ray) spectroscopy in an SEM (scanning electron microscope) were optimized for the detection of Eu(III) sorbed on diatom biosilica. The required stability of biosilica under a focused electron beam was extensively investigated. Using experimentally determined data of thermal properties, the temperature increase within biosilica exposed to an electron beam was simulated by finite element calculations based on results from Monte Carlo simulations of electron scattering. Complementary thermogravimetric studies substantiated a chemical stability of biosilica in a wide temperature range, confirming its suitability for long-lasting SEM investigations. In subsequent EDX measurements, characteristic Eu lines were detected. Eu was found to preferentially accumulate and aggregate on silica fragments. CL spectra were obtained for the Eu(III) reference material, EuCl3. For Eu-loaded biosilica, even parts without detectable Eu signal in the EDX spectra show significant Eu(III) signals in the CL spectra. This highlights the sensitivity of CL in studying f-element sorption. CL data showed that Eu(III) was distributed on the entire surface. In conclusion, this work demonstrates the merit of CL and EDX methods for sorption studies on biogenic materials.

Dickite and kaolinite in the Pb-Zn-Ag sulphide deposits of northern Kosovo (Trepča and Crnac)

Clay Minerals ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 67-79 ◽  
Author(s):  
S. S. Palinkaš ◽  
S. B. Šoštarić ◽  
V. Bermanec ◽  
L. Palinkaš ◽  
W. Prochaska ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Fluid Inclusion ◽  
Powder Diffraction ◽  
X Ray ◽  
Mineralogical Characteristics ◽  
Alteration Minerals ◽  
Sulphide Deposits ◽  
Scanning Electron

AbstractAlteration minerals dickite and kaolinite were detected in two hydrothermal Pb-Zn-Ag sulphide deposits in the northern Kosovo region. Dickite is associated with skarn mineralization in the Trepča (Stari Trg) deposit and kaolinite occurs in vein sulphide parageneses in the Crnac deposit. The mineralogical characteristics of dickite and kaolinite were determined by X-ray powder diffraction, Raman spectroscopy and scanning electron microscopy with EDS detector. Fluid-inclusion microthermometry and ion chromatography of leachates provided information on theP-T-Xconditions of the genesis of dickite at Trepča. It was formed at temperatures between 290 and 330ºC and pressures between 12 and 60 MPa from a fluid with salinity in the range 6–8.5 wt.% NaCl eq. and pH <5.5. Kaolinite was deposited from a fluid with minimum temperatures between 210 and 250ºC, minimum pressure of 1.7 to 3.7 MPa, and salinity between 4.6 and 5.1 wt.% NaCl eq. Both dickite and kaolinite are related to the acidic pre-mineralization phase in the deposits.

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