363 results on '"Celadonite"'
Search Results
2. 内蒙古阿拉善地区绿色戈壁玛瑙的宝石学特征与 致色成因研究.
- Author
-
张润清 and 杜景红
- Abstract
Copyright of Acta Petrologica et Mineralogica / Yanshi Kuangwuxue Zazhi is the property of Acta Petrologica et Mineralogica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
3. Painting Materials and Techniques of the Ajanta Wall Paintings
- Author
-
Shimadzu, Yoshiko, van den Berg, Klaas Jan, Series Editor, Burnstock, Aviva, Series Editor, Janssens, Koen, Series Editor, van Langh, Robert, Series Editor, Mass, Jennifer, Series Editor, Nevin, Austin, Series Editor, Lavedrine, Bertrand, Series Editor, Ormsby, Bronwyn, Series Editor, Strlic, Matija, Series Editor, Aoki, Shigeo, editor, Taniguchi, Yoko, editor, Rickerby, Stephen, editor, Mori, Michiyo, editor, Kijima, Takayasu, editor, Bomin, Su, editor, and Kirino, Fumiyoshi, editor
- Published
- 2021
- Full Text
- View/download PDF
4. Textural and genetic relationships between glauconite and celadonite at the nanoscale: two different structural-compositional fields.
- Author
-
Nieto, Fernando, Abad, Isabel, Bauluz, Blanca, and Reolid, Matías
- Subjects
GLAUCONITE ,CELADONITE ,VOLCANIC ash, tuff, etc. ,SCANNING electron microscopy ,SMECTITE ,X-ray diffraction - Abstract
Glauconite and celadonite coexist at the nanometre scale in Early Jurassic submarine volcanic rocks of the Betic Cordillera (southern Spain) as a result of microbial activity. Samples from the limit between the two micas, recognizable in scanning electron microscopy, have been extracted using the focussed ion beam technique and studied by high-resolution analytical electron microscopy. Both micas are present as randomly oriented differentiated small crystals in the boundary area. They define clearly distinct compositional fields with gaps affecting to Fe, Mg and K. At the lattice scale, celadonite shows a high degree of order, with homogeneous orientation of the visible lattice parameters being a difference from glauconite, formed by packets no more than 10-layers thick. Smectite layers were also detected alongside glauconite packets, in accordance with X-ray diffractograms which indicate that glauconite is a mica-smectite interstratification being more than 90% mica layers. The compositional gap indicates that celadonite is not the endmember of the glauconitic series and the two micas represent two different structural tendencies of mica, with glauconite having more distorted octahedral sheets, indicated by systematically higher b parameters than celadonite. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Origin of K-rich green clays within Late Cretaceous Deccan basalts: A local K-depository.
- Author
-
Singh, Pragya, Banerjee, Santanu, Wagh, Disha, Pande, Kanchan, and Bhattacharya, Satadru
- Subjects
- *
DECCAN traps , *FLOOD basalts , *CLAY , *OBSIDIAN , *PORE fluids , *ZEOLITES - Abstract
This study focuses on compositional diversity and origin of green clays within the Late Cretaceous volcaniclastic horizons (green boles) in Deccan volcanics based on petrographical, mineralogical and geochemical investigation on outcrop samples. Green boles, showing either sharp or gradational contacts with the underlying basalt, were comprised of three different green clays: type 1 dark green void-filling clay, type 2 light green clay formed by the alteration of volcanic lithic and vitric grains, and type 3 light green clay pellet formed by the alteration of fine-grained vitric materials. FTIR and XRD data indicated 10 Å (celadonite type) and 15 Å (smectite) as dominant clay constituents. The type 1 clay showed higher oct. Fe total (∼1.03 a.p.f.u.), Mg (∼0.62 a.p.f.u.) and lower oct. Al (∼0.34 a.p.f.u.) compared to types 2 and 3. Type 2 green clay showed two subtypes. Interlayer cations in type 2A and 2B averaged 0.86 and 0.72 a.p.f.u., respectively. The high K 2 O and interlayer cation of type 1 and 2A clays confirmed celadonite. Type 2B and 3 green clays, variably mixed with smectite and quartz, belonged to interlayer cation deficient mica category. The association of type 1 celadonite with Fe, Mg-smectite and Ca-zeolite indicated its formation from pore fluid with changing chemistry. The alteration of volcanic lithic and vitric fragments under weakly reducing conditions with steady supply of relevant cations formed type 2 and 3 green clays. The study of green clays in bole beds is crucial for understanding the wide compositional diversity of potassic clay associated with continental flood basalts. • Three varieties of K and Fe-rich green clays interlayered with Cretaceous basaltic flows. • Celadonite is the dominant clay in the bole beds along with smectite. • Celadonite shows wide spectrum of chemical composition. • Depositional redox condition affects the chemical composition of celadonite • Potassium content of celadonite derives from K-rich volcanic glasses. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Green earth pigments dispersions: Water dynamics at the interfaces.
- Author
-
Fanost, Agathe, Jaber, Maguy, de Viguerie, Laurence, Korb, Jean-Pierre, Levitz, Pierre E., Michot, Laurent J., Mériguet, Guillaume, and Rollet, Anne-Laure
- Subjects
- *
INTERFACE dynamics , *DISPERSION (Chemistry) , *SURFACE interactions , *PHYLLOSILICATES , *WATER - Abstract
The objective is to elucidate the multiscale dynamics of water within natural mixtures of minerals, green earth pigments that are mainly composed of phyllosilicates containing large amount of iron. In particular, the interaction of water with the different kinds of surfaces has to be probed. One issue is to examine the influence of surface type, basal or edge, on the dispersion quality. The study was carried out using 1H variable field NMR relaxometry on various green earth pigment dispersions and concentrations. To analyse the data, a new analytical model was developed for natural phyllosilicates containing large amount of paramagnetic centres. The proposed theoretical framework is able to fit the experimental data for various samples using few parameters. It allows to determining water diffusion and residence times in complex phyllosilicate dispersions. Furthermore, it makes it possible to differentiate the contribution of the basal and edge surfaces and their respective surface area in interaction with water. Moreover, NMR relaxation profile reveals to be highly sensitive to the structural aspect of the phyllosilicates and to the accessibility of water to iron, hence allowing to discriminate clearly between two very similar phyllosilicates (glauconite and celadonite) that are difficult to distinguish by standard structural methods. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Green Earth pigments aqueous dispersions: NMR relaxation rates dataset
- Author
-
Agathe Fanost, Maguy Jaber, Laurence de Viguerie, Jean-Pierre Korb, Pierre E. Levitz, Laurent J. Michot, Guillaume Mériguet, and Anne-Laure Rollet
- Subjects
Celadonite ,Glauconite ,Phyllosilicate ,Fast Field Cycling NMR relaxometry ,Water surface interaction ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
The data presented here are related to the research paper entitled “Green Earth pigments dispersions: water dynamics at the interfaces”. The nuclear magnetic resonance (NMR) relaxometry data are provided for various aqueous Green Earth (GE) pigments dispersions with volume fraction spanning approximately from 0.1 to 0.5. For two of them (Cyprus GE and Bohemian GE), the NMR relaxation profiles from 10 kHz to 30 MHz (1H frequency) is given for several temperatures spanning from 293 to 318K. In addition, the X-ray diffraction pattern is provided for France GE (Kremer pigments) for the identification of the main mineral component. The nitrogen gas isotherms are provided for Cyprus GE and Bohemian GE.
- Published
- 2020
- Full Text
- View/download PDF
8. Authigenic Green Mica in Interflow Horizons within Late Cretaceous Deccan Volcanic Province, India and Its Genetic Implications
- Author
-
Pragya Singh, Santanu Banerjee, Kanchan Pande, Satadru Bhattacharya, Subham Sarkar, and Emilia Le Pera
- Subjects
celadonite ,Fe-smectite ,authigenic minerals ,green bole ,Deccan volcanic province ,volcaniclastic ,Mineralogy ,QE351-399.2 - Abstract
Green authigenic mica, i.e., celadonite, is commonly associated with submarine alteration of basic igneous rock. However, very few studies have reported the formation of celadonite under nonmarine conditions. An integrated study involving field investigation, petrography, mineralogy, and mineral chemistry highlighted the origin of celadonite in two clay-rich horizons (green boles) of the Late Cretaceous Deccan volcanic province. Within the Salher green bole, the celadonite occurred as the dissolution and alteration of plagioclase, volcanic glass, and pore-filling cement. In the case of the Pune green bole, the celadonite was formed by the alteration of plagioclase, pyroxene, and precipitation as film within intergranular pores, along with zeolite. The celadonite in the Salher green bole exhibited slightly lower K2O and Fe2O3 and higher Al2O3 than in the Pune. The mineral chemistry of the former showed a composition closer to ferro-aluminoceladonite. Although the mineral chemistry of celadonite overlaps with glauconite, the distinct 10 Å and 15 Å reflections in XRD, euhedral lath and honeycomb morphology under SEM, and characteristic absorption bands in VNIR spectroscopy (0.4–2.5 µm) and FTIR spectroscopy (400–4000 cm−1) identified celadonite and Fe-smectite within green boles. The green boles were formed either by the alteration of a volcaniclastic deposit in local pools of water or by the in situ alteration of the fragmentary flow top. The present study is significant due to the occurrence of celadonite in a nonmarine environment, as it otherwise forms under submarine conditions.
- Published
- 2022
- Full Text
- View/download PDF
9. COMPOSITIONAL ANALYSIS AND CROSS-CULTURAL EXAMINATION OF BLUE AND BLUE-GREEN POST-FIRE COLORANTS ON TOLITA-TUMACO CERAMICS.
- Author
-
Reiss, Breanna F., Spilde, Michael, and Peterson, Eric
- Subjects
- *
CROSS-cultural studies , *BLUE , *SCANNING electron microscopy , *CERAMICS - Abstract
This study explores blue and blue-green post-fire colorants used by the Tolita-Tumaco culture of ancient coastal Ecuador and Colombia. Using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), one sample each of blue and blue-green colorants taken from ceramic surfaces were tested to identify the mineral compositions present. The blue-green sample from a ceramic sherd found at La Tolita was identified as celadonite or glauconite. XRD and SEM tests on a blue sample from a ceramic figurine fragment found along the Rio Mataje was tentatively identified the sodic amphiboles glaucophane and riebeckite. XRD tests further suggest other minerals that may affect the color, including cordierite, antigorite, and celadonite or glauconite. Cross-cultural comparison provides insight on how coastal Ecuadorian groups used these colorants and exemplifies the innovative nature behind their creation. It appears that the development of Ecuadorian blue and blue-green derived from local colorant traditions, with some localized pigment sources. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
10. Terra verde: Overcoming the problem of transparency by crystal engineering.
- Author
-
Micallef, Duncan, Spiteri, Rebecca, Baisch, Ulrich, and Vella-Zarb, Liana
- Subjects
- *
TRANSPARENCY (Optics) , *CRYSTALS , *GLAUCONITE , *CELADONITE , *OPACITY (Optics) - Abstract
Terra verde, or Green Earth, a naturally-occurring mineral and green pigment consisting of celadonite or glauconite, is one of the most commonly-used pigments in works of art and their conservation. Its widespread use is owed primarily to its insensitivity to light, its neutral pH, and its high stability in air and moisture – attributes that collectively make it virtually unreactive with other components in an artefact. Notwithstanding this, the use of terra verde in the conservation of objects of cultural heritage is hindered due to its minimal tinting strength and hiding power, which makes the pigment effectively transparent when applied on the canvas with the most common binding media. This gives rise to problems in retouching during the restoration process. We report a robust and reliable method to overcome the problem of transparency through the application of crystal engineering techniques on the pigment Verona Green Earth, or Verona Terra Verde (VTV). The purchased pigment was co-crystallised with a selection of different co-formers and analysis was carried out on both starting compound and product via IR and XRF spectroscopy, hot-stage microscopy and powder X-ray diffraction. The results of the experiments conducted show an increase in the pigment's opacity without affecting its colour intensity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
11. Hydrothermal Formations on the Pervenets Rise, Japan Sea.
- Author
-
Astakhova, N. V., Lopatnikov, E. A., Mazherovsky, V. A., and Yaroshchuk, E. I.
- Subjects
- *
HYDROTHERMAL deposits , *SUBMARINE volcanoes , *CELADONITE , *FERROMANGANESE , *GEOLOGICAL surveys , *GEOCHEMISTRY , *VOLCANIC ash, tuff, etc. - Abstract
This paper provides information on the structure, chemical composition, and concentrations of microelements in ferromanganese crusts and siliceous crusts sampled on the Pervenets Rise, Sea of Japan. The crusts were formed by cementation of small fragments of green clays (celadonite) by manganese hydroxides (todorokite and birnessite) or by silica. The primary process involved the generation of celadonite, which was deposited as ore-bearing hydrothermal brine that was discharged in the caldera of the volcano or on its slopes. The crusts have a structure that indicates their formation during diffuse percolation of gas-charged hydrothermal brine along fissures or weakened zones in volcanic rocks and subsequent cementation of the resulting celadonite deposits with manganese or siliceous oxides. The manganese and the siliceous mineralization are separated over time, as well as, frequently, in space, and are more local. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
12. Pseudomorphs after Lawsonite from Syros, Greece.
- Author
-
Hamelin, Clémentine, Brady, John B, Cheney, John T, Schumacher, John C, Able, Lindsey M, and Sperry, Arianne J
- Subjects
- *
PSEUDOMORPHS , *LAWSONITE , *FACIES , *CELADONITE - Abstract
Syros is part of the Attic–Cycladic blueschist belt and consists principally of marbles, schists, and metabasites that have been metamorphosed to the blueschist- to eclogite-facies at about 52 Ma, with a greenschist-facies overprint beginning at about 25 Ma. Distinct, whitish clusters of sub-millimeter-sized grains organized into orthorhombic polyhedral shapes occur in a variety of the blueschists. These clusters are interpreted to be pseudomorphs after lawsonite based on their shape, chemistry, and the presence of rare relict lawsonite in a few of the clusters. A considerable range in observed pseudomorph modes reflects both variety in rock compositions and the extent of greenschist overprinting. Most pseudomorphs contain epidote-group minerals (clinozoisite/epidote), similar to the composition of ideal lawsonite, except for added Fe and lost water. Many contain white mica (phengite, paragonite, muscovite), which requires the addition of K and/or Na to the original lawsonite. In some cases, the pseudomorph is largely mica, so that Ca must have been lost to an epidote mineral, amphibole, or calcite in the matrix. Phengite in the pseudomorphs typically has a lower celadonite content than phengite in the matrix. It appears that the mica has changed its composition by breakdown in the matrix, K diffusion, and regrowth in the pseudomorph. We propose that lawsonite breakdown must be in part driven by the reaction of lawsonite with the celadonite content of phengitic mica in the matrix, to form celadonite-poor (muscovite-rich) white mica in the pseudomorph. The preservation of the lawsonite shape in the pseudomorphs in weakly deformed rocks appears to be due to the relative immobility of Al during the pseudomorphing reactions, with K, Na, and Fe moving to the pseudomorphs and Ca and H2O leaving. The only source of K in these rocks is phengite, which should become less rich in celadonite with an increase in temperature, needed to drive lawsonite breakdown. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
13. Identification of iron in Earth analogues of Martian phyllosilicates using visible reflectance spectroscopy: Spectral derivatives and color parameters.
- Author
-
Sánchez-Marañón, Manuel, Cuadros, Javier, Michalski, Joseph R., Melgosa, Manuel, and Dekov, Vesselin
- Subjects
- *
PHYLLOSILICATES , *IRON , *CLAY minerals , *NONTRONITE , *CELADONITE - Abstract
Abstract A range of phyllosilicate compositions have been detected spectroscopically on Mars, but the largest fraction by far corresponds to clay minerals rich in Fe and Mg. Given that most of our understanding of Martian clays comes from remote sensing data, it is critically important to explore the details of how compositional variation affects spectral features of phyllosilicates. The greatest efforts have focused so far on near-infrared (NIR) spectroscopy. Recently, ambiguities have been detected in the NIR spectra of 2:1 phyllosilicates with intermediate Fe Mg content that preclude mineral and chemical discrimination. Such ambiguities highlight the relevance of exploring the visible spectral range as a complementary tool to characterize Martian phyllosilicates precisely. This article reports the investigation of laboratory reflectance spectra (330–800 nm) from 34 Earth analogues of Martian phyllosilicates with a wide range of Mg Fe composition, including nontronite, celadonite and saponite end-members, as well as interstratified glauconite-nontronite, talc-nontronite, and talc-saponite. The spectra indicated the presence of Fe(III) by absorption modulations and a decrease in total reflectance, especially in samples with tetrahedral Fe(III). Absorption bands at 370 and 420 nm were diagnostic of octahedrically and tetrahedrally coordinated Fe(III), respectively. Band amplitudes in the second derivative of the Kubelka-Munk function correlated positively with Fe(III) content (R 2 > 0.8). Standard color analyses of the visible reflectance spectra under the CIE illuminant D65 indicated that the CIELAB color parameter a * 10 was positively correlated with tetrahedral Fe(III), b * 10 was positively correlated with octahedral Fe(III), and L * 10 was negatively correlated with Fe(III) in both structural sites. Because Fe(II) was in relatively low amount, it did not provide clear spectral evidence. Multiple regression models using the amplitude of the diagnostic absorption bands predicted well absolute Fe content in the phyllosilicates (R 2 = 0.89) and the ratio Fe/(Fe + Mg + Al) (R 2 = 0.84). CIELAB color parameters improved the prediction of total Fe (R 2 = 0.92) and the ratio Fe/(Fe + Mg + Al) (R 2 = 0.93). Application of these analyses to Martian data has challenges set by Fe oxide dust coating and spatial and spectral resolution. However, these results mark an avenue to develop testable tools using visible-wavelength spectral data from both satellite and lander probes to help establishing Fe content and mineral identification of Martian phyllosilicates. Highlights • Visible-range spectra of phyllosilicates shaped by Fe content and site occupancy. • Phyllosilicate Fe content is predicted well by 2nd-derivative and color analyses. • Vis spectra from Martian rocks with phyllosilicates comparable to lab spectra. • 2nd-derivative and color analyses hopeful tool to estimate Fe in Martian clays. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
14. Distinguishing Features and Identification Criteria for K-Dioctahedral 1M Micas (Illite-Aluminoceladonite and Illite-Glauconite-Celadonite Series) from Middle-Infrared Spectroscopy Data
- Author
-
Bella B. Zviagina, Victor A. Drits, and Olga V. Dorzhieva
- Subjects
ir spectroscopy ,illite ,aluminoceladonite ,glauconite ,celadonite ,Mineralogy ,QE351-399.2 - Abstract
A representative collection of K-dioctahedral 1M micas ranging in composition from (Mg, Fe)-poor illites to aluminoceladonites through Mg-rich illites (Fe-poor varieties) and from Fe-bearing, Mg-rich illites to celadonites through Fe-illites, Al-glauconites and glauconites (Fe-bearing varieties) was studied by Fourier-transform infrared (FTIR) spectroscopy in the middle-infrared region. Analysis and comparison of the relationships between the band positions and cation compositions of Fe-poor and Fe-bearing K-dioctahedral micas provided a generalized set of FTIR identification criteria that include the band positions and profiles in the regions of Si−O bending, Si−O stretching, and OH-stretching vibrations. FTIR data allow unambiguous identification of illites, aluminoceladonites, and celadonites, as well as distinction between Fe-illites and illites proper, as well as between Al-glauconites and glauconites. Specifically, a sharp maximum from the AlOHMg stretching vibration at ~3600 cm−1, the presence of a MgOHMg stretching vibration at 3583−3585 cm−1, as well as characteristic band positions in the Si−O bending (435−439, 468−472 and 509−520 cm−1) and stretching regions (985−1012 and 1090−1112 cm−1) are clearly indicative of aluminoceladonite. The distinction between Fe-illites and Al-glauconites, which have similar FTIR features, requires data on cation composition and unit-cell parameters.
- Published
- 2020
- Full Text
- View/download PDF
15. Determination of Minor Contents of Smectite Layers in the Dispersed Dioctahedral K-bearing Micaceous Minerals of the Illite, Aluminoceladonite, and Glauconite Composition.
- Author
-
Sakharov, B. A. and Drits, V. A.
- Subjects
- *
SMECTITE , *ILLITE , *CELADONITE , *GLAUCONITE , *ETHYLENE glycol - Abstract
A theoretically substantiated technique has been elaborated for the precise determination of minor contents of smectite layers in the dioctahedral mixed-layer structures with a disordered alternation of K-bearing micaceous and ethylene glycol-saturated smectite layers. It is shown that observed positions of the possible mixed-layer mica-smectite structures in the d(003)obs-d(007)obs or 2θ(003)obs-2θ(007)obs diagrams are distributed along a set of parallel straight lines. Data points of each straight line correspond to the mixed-layer structures with one and the same content of smectite layers. A complete matching of theoretical model was recorded in the positions of d(003)obs-d(007)obs and 2θ(003)obs-2θ(007)obs pairs of the basal reflections determined in diffractograms simulated for 160 two-component mixed-layer mica-smectite structures differing in the thickness of alternating layers and their relative content. We studied samples of the dioctahedral K-bearing micas of the glauconite, illite, and aluminoceladonite composition with different thickness of micaceous layers. Positions of the mixed-layer structures of the studied samples on the 2θ(003)obs-2θ(007)obs and d(003)obs-d(007)obs plots make it possible to visually determine the content of smectite layers in each structure accurate to 0.5%. The content of smectite layers in the studied samples varied from 2 to 15%. We obtained equations relating the thickness of smectite and micaceous layers for a specified content of smectite layers. They make it possible to determine the thickness correlation between specified mica and smectite layers. Analogous equations can be used to calculate the wsm value in each sample for specified experimental values of d(001)mc and d(001)sm and d(003)obs or d(007)obs. The wsm values coincide within an error limit of 0.2% with those based on the visual estimates in plots. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
16. Green and blue pigments in Roman wall paintings: A challenge for Raman spectroscopy
- Author
-
Susana E. Jorge-Villar and Howell G. M. Edwards
- Subjects
Azurite ,media_common.quotation_subject ,Mineralogy ,Malachite ,Art ,engineering.material ,Indigo ,Chrysocolla ,Egyptian blue ,chemistry.chemical_compound ,chemistry ,visual_art ,visual_art.visual_art_medium ,engineering ,Celadonite ,General Materials Science ,Spectroscopy ,Lazurite ,Verdigris ,media_common - Abstract
In Roman wall paintings, blue and green colours are less commonly encountered than red and yellow and were more expensive. Despite this, Pliny and Vitruvius describe the more common compounds used for these pigments, translated today as azurite, lazurite, chrysocolla, indigo and Egyptian blue for blues and verdigris, malachite, celadonite, glauconite and chlorite for greens. A confusion in their nomenclature is often found in the most common blue pigment that is the first manufactured compound, Egyptian blue. For greens, celadonite and glauconite were usual and called generically ‘green earths’, but they prove to be difficult to characterize analytically. In this paper, we evaluate the Raman spectroscopic identification of the characteristic Roman blue and green pigments as used in wall paintings using two different laser wavelengths (green and near infrared) and clarify their nomenclature.
- Published
- 2021
17. Polychromy Analysis on Cypriot Archaic Statues by Non- and Micro-Invasive Analytical Techniques.
- Author
-
Gasanova, S., Pagès‐Camagna, S., Andrioti, M., Lemasson, Q., Brunel, L., Doublet, C., and Hermon, S.
- Subjects
- *
POLYCHROMY , *LIMESTONE sculpture , *TERRA-cotta sculpture , *CELADONITE , *COPPER - Abstract
The polychromy of limestone and terracotta statues from Cyprus attributed to the sixth to fifth centuries bc is analysed using non- and micro-invasive techniques in order to shed light on the use of pigments during the studied period. The strengths and limitations of these methods for the present application are discussed. The identified pigments are iron-containing compounds (red, yellow, green earths and iron-manganese black). No copper-containing compounds were detected on the studied objects, despite the wide availability of copper minerals in Cyprus. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
18. A multimethodic approach for the characterization of manganiceladonite, a new member of the celadonite family from Cerchiara mine, Eastern Liguria, Italy.
- Author
-
LEPORE, G. O., BINDI, L., DI BENEDETTO, F., MUGNAIOLI, E., VITI, C., ZANETTI, A., CIRIOTTI, M. E., and BONAZZI, P.
- Subjects
- *
CELADONITE , *MINES & mineral resources , *TRANSMISSION electron microscopy , *CATIONS , *LASER ablation , *RAMAN spectroscopy - Abstract
In the manganesiferous ores associated with the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), a new Mn-bearing mineral belonging to the mica group has been recently found and characterized. High resolution transmission electron microscopy and electron diffraction tomography studies confirm that the mineral belongs to the mica group. Unit-cell parameters from the powder diffraction pattern are: a = 5.149(1), b = 8.915(1), c = 10.304(1) Å, β = 102.03(1)°, space group C2 or C2/m. On the basis of the electron paramagnetic resonance spectroscopic results, the Mn4+ content represents a very subordinate fraction of the total Mn, the remaining occurring as Mn3+. The Raman spectrum clearly indicates the presence of OH groups in the structure. Laser-ablation inductively-coupled-plasma mass-spectrometry measurements assess the presence of considerable amounts of Li. Assuming all Mn as Mn3+ and 22 negative charges, the empirical formula can be expressed as: (K0.83□0.17)(Mn3+ 1:14Mg0.80Li0.20Fe3+ 0: 02)(Si3.89Al0.10)O10[(OH)1.92F0.08] with the sum of the octahedral cations indicating a 'transitional' character between a di- and a tri-octahedral structure. This formula corresponds ideally to the Mn3+ analogue of celadonite, thus expanding the range of solid solution in the celadonite family. The ideal end-member formula KMn3+MgSi4O10(OH)2 can be easily related to celadonite by the homovalent substitution VIMn3+ → VIFe3+. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, (IMA 2015-052). [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. An innovative combination of non-invasive UV–Visible-FORS, XRD and XRF techniques to study Roman wall paintings from Seville, Spain.
- Author
-
Garofano, Isabel, Perez-Rodriguez, Jose Luis, Robador, Maria Dolores, and Duran, Adrian
- Subjects
- *
ROMAN painting , *COLORIMETRY , *FOURIER transform infrared spectroscopy , *CELADONITE , *GLAUCONITE - Abstract
This study attempts to establish the advantages and limitations of the combined use of portable UV–Vis-FORS and XRF-XRD portable equipment for the non-invasive characterisation of pigments from Roman wall paintings from Seville, Spain, dated to the first and second century AD. XRD revealed the presence of calcite, dolomite and aragonite, indicating the colour white. Egyptian blue was identified using FORS and XRF, and additional information was obtained with XRD. For the colour green, FORS and mainly FTIR and colorimetry enabled the distinction between glauconite and celadonite, although other techniques were necessary to classify all components of the green areas by determining the presence of cuprorivaite, chlorite and chromium. For the colours yellow and red, the presence of goethite, yellow ochre, cinnabar and haematite was confirmed using FORS and XRF in some cases; the results were corroborated by XRD. Chromatic characterisation and the values of inflection points of FORS spectra enabled a better differentiation between reddish colours (orange, brown, purple and pink). The XRD and XRF techniques revealed that violet was created by mixing red haematite and Egyptian blue and slight variations in FORS spectra confirmed this. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. Chromceladonite from the Southern Sarany Chromite Deposit (Northern Urals)
- Author
-
S. G. Sustavov, E. S. Shagalov, and D. A. Khanin
- Subjects
geography ,geography.geographical_feature_category ,Mineral ,Geochemistry ,Geology ,Massif ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,Geochemistry and Petrology ,Uvarovite ,engineering ,Celadonite ,Economic Geology ,Chromite ,010503 geology ,Chlorite ,Chemical composition ,Quartz ,0105 earth and related environmental sciences - Abstract
—Chromceladonite in chromitites of the Southern Sarany chromium deposit (the Urals) occurs in two mineral associations: as crusts of acicular grains on uvarovite crystals and in thin-scale aggregates together with quartz and chlorite in brecciated zones developed after chromitites. The chemical composition of chromceladonite (wt %) is K2O 9.4, MgO 6.8, Cr2O3 17.1, SiO2 51.7, Al2O3 8.5, CaO 0.1, FeO 0.2, H2O+ 5.7. The sum is 99.7. Empirical formula: K0.82(Cr0.93Mg0.70 ⋅ Al0.25Ti0.05Fe0.01)Σ1.94[(Si3.56Al0.44)Σ4.00(O9.39OH0.61)Σ10(OH)2. Parameters of an elementary sell: a = 5.271(5), b = 9.015(6), c = 10.171(7) A, β = 101.82(8)°, V = 475(1) A3. The formation temperature of celadonite is as high as 300°C. A source of potassium for chromceladonite can be both country black shales and phlogopite-bearing rocks of the Southern Sarany massif.
- Published
- 2019
21. Non-Destructive Multi-Analytical Approach to Study the Pigments of Wall Painting Fragments Reused in Mortars from the Archaeological Site of Pompeii (Italy)
- Author
-
Domenico Miriello, Andrea Bloise, Gino M. Crisci, Raffaella De Luca, Bruno De Nigris, Alberta Martellone, Massimo Osanna, Rossella Pace, Alessandra Pecci, and Nicola Ruggieri
- Subjects
micro-Raman spectroscopy ,portable XRF ,colorimetry ,hematite ,cuprorivaite ,celadonite ,goethite ,Mineralogy ,QE351-399.2 - Abstract
During the excavations carried out in Via di Mercurio (Regio VI, 9, 3) in Pompeii, in 2015, some red, green, black, and brown wall painting fragments were found in the preparatory layer of an ancient pavement which was probably built after the 62 AD earthquake. These fragments, derived from the rubble, were used as coarse aggregate to prepare the mortar for building the pavement. The wall painting fragments are exceptionally well preserved, which is an uncommon occurrence in the city of Pompeii. However, as they were enclosed in the mortar, the wall painting fragments were protected from the high temperatures (probably ranging between 180 °C and 380 °C) produced by the eruption in 79 AD. The pigmented outer surface of each sample was analyzed using a non-destructive multi-analytical approach, by combining spectrophotometric colorimetry and portable X-ray fluorescence with micro-Raman spectroscopy. The compositional characterization of the samples revealed the presence of cuprorivaite, goethite, and celadonite in the green pigments; hematite in the red pigments; goethite in the brown pigment; and charcoal in the black pigment. These data probably provide us with the most “faithful picture” of the various red, green, black, and brown pigments used in Pompeii prior to the 79 AD eruption.
- Published
- 2018
- Full Text
- View/download PDF
22. Textural and genetic relationships between glauconite and celadonite at the nanoscale: Two different structural-compositional fields
- Abstract
Glauconite and celadonite coexist at the nanometre scale in Early Jurassic submarine volcanic rocks of the Betic Cordillera (southern Spain) as a result of microbial activity. Samples from the limit between the two micas, recognizable in scanning electron microscopy, have been extracted using the focussed ion beam technique and studied by high-resolution analytical electron microscopy. Both micas are present as randomly oriented differentiated small crystals in the boundary area. They define clearly distinct compositional fields with gaps affecting to Fe, Mg and K. At the lattice scale, celadonite shows a high degree of order, with homogeneous orientation of the visible lattice parameters being a difference from glauconite, formed by packets no more than 10-layers thick. Smectite layers were also detected alongside glauconite packets, in accordance with X-ray diffractograms which indicate that glauconite is a mica-smectite interstratification being more than 90 % mica layers. The compositional gap indicates that celadonite is not the endmember of the glauconitic series and the two micas represent two different structural tendencies of mica, with glauconite having more distorted octahedral sheets, indicated by systematically higher b parameters than celadonite.
- Published
- 2021
23. Textural and genetic relationships between glauconite and celadonite at the nanoscale: Two different structural-compositional fields
- Author
-
Isabel Abad, Fernando Nieto, Blanca Bauluz, Matías Reolid, Ministerio de Ciencia, Innovación y Universidades (España), and Junta de Andalucía
- Subjects
geography ,geography.geographical_feature_category ,Materials science ,Scanning electron microscope ,Mineralogy ,engineering.material ,Nanomaterial ,Underwater environment ,Volcanic rock ,Microbial activity ,Homogeneous ,Celadonite ,Mica ,engineering ,Glauconite ,Texture ,Smectite ,Clay minerals ,Nanoscopic scale ,QE351-399.2 - Abstract
We acknowledge the use of the LMA-INA (Universidad de Zaragoza) for access to dual beam equipment and expertise, the technical and human support provided by CICT of Universidad de Jaén (UJA, MINECO, Junta de Andalucía, FEDER), and the use of the PANalytical X'Pert Pro diffractometer of the Departamento de Mineralogía y Petrología, Universidad de Granada, Spain. María del Mar Abad is especially recognized for helping with the HRTEM work. The access to the HAADF FEI TITAN G2 microscope and the Philips CM20 (STEM) microscope was facilitated by the Centro de Instrumentación Científica of the Universidad de Granada. Thanks are extended to Javier Cuadros and an anonymous reviewer for their critical reviews and very helpful comments and suggestions., Glauconite and celadonite coexist at the nanometre scale in Early Jurassic submarine volcanic rocks of the Betic Cordillera (southern Spain) as a result of microbial activity. Samples from the limit between the two micas, recognizable in scanning electron microscopy, have been extracted using the focussed ion beam technique and studied by high-resolution analytical electron microscopy. Both micas are present as randomly oriented differentiated small crystals in the boundary area. They define clearly distinct compositional fields with gaps affecting to Fe, Mg and K. At the lattice scale, celadonite shows a high degree of order, with homogeneous orientation of the visible lattice parameters being a difference from glauconite, formed by packets no more than 10-layers thick. Smectite layers were also detected alongside glauconite packets, in accordance with X-ray diffractograms which indicate that glauconite is a mica-smectite interstratification being more than 90 % mica layers. The compositional gap indicates that celadonite is not the endmember of the glauconitic series and the two micas represent two different structural tendencies of mica, with glauconite having more distorted octahedral sheets, indicated by systematically higher b parameters than celadonite., MCIU-AEIFEDER PGC2018-094573-B-I00 ,PID2019-104624RB-I00 and RTI2018-093419-B-I00, Junta de Andalucia RNM-325, RNM-200 and RNM-179, Gobierno de Aragon E18_17R, European Fund
- Published
- 2021
24. Experimental data for high-temperature decomposition of natural celadonite from banded iron formation.
- Author
-
Savko, K., Piliugin, S., and Bazikov, N.
- Subjects
- *
HIGH temperature chemistry , *CHEMICAL decomposition , *CELADONITE , *ALUMINUM oxide , *MAGNETITE - Abstract
Three experiments were set up to evaluate conditions for the high-temperature decomposition of celadonite from a banded iron formation in an alumina-free system and identify its decomposition products. It was estimated that at 650 and 750 °C, with a NiNiO buffer and pressure of 3 kbar, celadonite completely decomposes and the decomposition products were tetraferribiotite, magnetite and quartz. Under more oxidizing conditions (hematite-magnetite buffer instead of NiNiO), ferrous potassium feldspar sanidine forms instead of magnetite. During the celadonite decomposition in oxidizing conditions more magnesian and aluminous tetraferribiotite, along with ferrous sanidine, are formed than at reducing conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
25. Green pigments of Roman mural paintings from Seville Alcazar.
- Author
-
Perez-Rodriguez, Jose Luis, de Haro, Maria del Carmen Jimenez, Siguenza, Belinda, and Martinez-Blanes, José María
- Subjects
- *
ROMAN mural painting & decoration , *X-ray diffraction , *CHROMIUM oxide , *CELADONITE - Abstract
We report here a study of 30 fragments of green wall paintings from Roman times found in the Patio de Banderas excavation in Seville Alcazar. The sample characterisation was realised using optical microscopy, colourimetry, infrared and micro-Raman spectroscopy, X-ray diffraction, and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. The study of these pigments is important because it can help determine the source or the pictorial technique used. The samples studied in this work have been divided into two groups, according to the composition of their green pigments. In the first group, celadonite has been characterised as the primary component of the green colour; chlorite was also detected. Particles constituted by chromium accompanied by aluminium, iron and zinc were found in all studied samples of this group. Chlorite and chromium oxide could also be responsible for the green colour. The presence of chromium suggested the presence of green colour pigment from Verona. In the second group, a mixture of celadonite and glauconite was detected and could be responsible for the green colour observed. The addition of refracting material such as Egyptian blue was also used. A mixture of Egyptian green and Egyptian blue together with celadonite and glauconite was also found. Four classes of intonaco were recognised and classified based upon the composition of the aggregates. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
26. Experimental exploration of volcanic rocks-atmosphere interaction under Venus surface conditions
- Author
-
Annick Cathala, Sébastien Fabre, Thierry Aigouy, Patrick Pinet, Gilles Berger, Alain Pages, Jerôme Esvan, Anastassia Y. Borisova, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Lomonosov Moscow State University (MSU), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Centre-Est (Cerema Direction Centre-Est), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), CEDRAT TECHNOLOGIES (CTEC), Cedrat Technologies, Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'Ecologie Marine (ECOMAR), Université de La Réunion (UR), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Centre National d'Études Spatiales - CNES (FRANCE), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Institut de Recherche pour le Développement - IRD (FRANCE), Lomonosov Moscow State University - MSU (RUSSIA), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), and Centre Interuniversitaire de Recherche et d'Ingénierie des Matériaux - CIRIMAT (Toulouse, France)
- Subjects
Materials science ,010504 meteorology & atmospheric sciences ,[PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Matériaux ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Mineralogy ,Venus ,engineering.material ,01 natural sciences ,Magnesioferrite ,Experimental ,chemistry.chemical_compound ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Pumice ,0103 physical sciences ,Gas transfer ,Venus surface ,010303 astronomy & astrophysics ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences ,Basalt ,geography ,Olivine ,geography.geographical_feature_category ,biology ,Astronomy and Astrophysics ,biology.organism_classification ,Silicate ,Volcanic rock ,chemistry ,13. Climate action ,Space and Planetary Science ,engineering ,Celadonite ,Alteration - Abstract
International audience; This study presents an inventory of possible chemical reactions affecting, or having affected, the Venus surface. Fluid rock reactions are simulated using experiments under conditions close to the present surface. Slabs or powder of several natural and synthetic silicate material (crystalline fresh basalt, altered basalt, obsidian, pumice and basalt glass) were reacted at 475°C in CO 2-H 2 O-H 2 S-SO 2-CO gas mixture. Most of the runs were carried out at roughly 90 bars with a duration of one week, some experiments having longer (one month) or shorter (one day) durations. The role of H 2 O content was explored through a wide range of water pressure: from dry gas for the current Venus conditions up to 590 bars (86%H 2 O) for early Venus (or other early terrestrial planets). The gas phase was sampled before the completion of the runs for chemical analysis of major gas components (CO, H 2 S, SO 2) as well as trace elements possibly released by the rocks. The altered samples were examined by a suite of mineralogical and chemical techniques (scanning and transmission electron microscopy, X-ray diffraction and spectroscopy). In dry atmosphere, the redox potential of the gas was close to the Ni/NiO buffer (−21.3 to −27.3 log fO 2), thus close to the current Venus conditions. The sample alteration is tenuous and limited to surface oxidation of glasses and coating of olivine by iron oxides, as well as the general deposition of (Ca,Na)SO 4 at the sample surface. The oxidation of glass is reflected in the formation of magnesioferrite under the surface and is accompanied by the release of Ca, Mg and Na into the gas phase or mineralized as sulfate at the surface. In wet atmosphere, obsidian recrystallizes into a mixture of plagioclase and amphibole while basaltic glass produced non-expandable clays minerals: chlorite-type (2:1:1) at the surface and likely celadonite (2:1) below the surface. Olivine is preserved. Using obsidian (the most alterable material) as a proxy of aluminosilicates, we discuss the surface reactions operating under supercritical conditions, and we used a shrinking-core equation for modeling the long-term reactions. These parametric exploration offer new insights into processes having affected the surface of Venus and contribute to the discussion of open questions such as the fate of water or the lifetime of vitreous dust or fine grain material if present in the current or past Venusian environment. Longer duration experiments will provide more kinetic parameters that can be extrapolated to the geologic history of Venus.
- Published
- 2019
27. Hydrothermal formations of pervenets rise (the Sea of Japan)
- Author
-
N. V. Astakhova, E. A. Lopatnikov, E. I. Jaroshhuk, and A. V. Mozherovsky
- Subjects
geography ,geography.geographical_feature_category ,Birnessite ,Geochemistry ,engineering.material ,Cementation (geology) ,Ferromanganese ,Hydrothermal circulation ,Volcanic rock ,Todorokite ,engineering ,Celadonite ,Caldera ,Geology - Abstract
The data are given on the structure, chemical composition, and content of microelements in the ferromanganese and siliceous crusts of Pervenets Rise (the Sea of Japan). The crusts resulted from the cementation of small fragments of green clays (celadonite) with hydroxides of manganese (todorokite and birnessite) or silica. Initial was the formation of celadonite deposited during the eruption of ore-bearing hydrothermal solutions in the volcano caldera or on its slopes.The features of the crust structure show that they were originated through the diffusive infiltration of gas-hydrothermal solutions along the fractures or weakened zones in volcanic rocks and subsequent cementation of the celadonite already formed occurrences with manganese or siliceous oxides. The manganese and siliceous mineralization is separated in time and often in space and demonstrate more local distribution.
- Published
- 2019
28. Terra verde: Overcoming the problem of transparency by crystal engineering
- Author
-
Rebecca Spiteri, Liana Vella-Zarb, Ulrich Baisch, and Duncan Micallef
- Subjects
Archeology ,Opacity ,Materials Science (miscellaneous) ,010401 analytical chemistry ,Mineralogy ,02 engineering and technology ,Conservation ,Transparency (human–computer interaction) ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Chemistry (miscellaneous) ,engineering ,Environmental science ,Celadonite ,Neutral ph ,0210 nano-technology ,General Economics, Econometrics and Finance ,Glauconite ,Spectroscopy - Abstract
Terra verde, or Green Earth, a naturally-occurring mineral and green pigment consisting of celadonite or glauconite, is one of the most commonly-used pigments in works of art and their conservation. Its widespread use is owed primarily to its insensitivity to light, its neutral pH, and its high stability in air and moisture – attributes that collectively make it virtually unreactive with other components in an artefact. Notwithstanding this, the use of terra verde in the conservation of objects of cultural heritage is hindered due to its minimal tinting strength and hiding power, which makes the pigment effectively transparent when applied on the canvas with the most common binding media. This gives rise to problems in retouching during the restoration process. We report a robust and reliable method to overcome the problem of transparency through the application of crystal engineering techniques on the pigment Verona Green Earth, or Verona Terra Verde (VTV). The purchased pigment was co-crystallised with a selection of different co-formers and analysis was carried out on both starting compound and product via IR and XRF spectroscopy, hot-stage microscopy and powder X-ray diffraction. The results of the experiments conducted show an increase in the pigment's opacity without affecting its colour intensity.
- Published
- 2019
29. Hydrothermal Formations on the Pervenets Rise, Japan Sea
- Author
-
E. A. Lopatnikov, V. A. Mazherovsky, N. V. Astakhova, and E. I. Yaroshchuk
- Subjects
geography ,geography.geographical_feature_category ,Birnessite ,Metals and Alloys ,Geochemistry ,02 engineering and technology ,engineering.material ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,Cementation (geology) ,01 natural sciences ,Ferromanganese ,Hydrothermal circulation ,Volcanic rock ,020303 mechanical engineering & transports ,Geophysics ,0203 mechanical engineering ,Todorokite ,engineering ,Caldera ,Celadonite ,Geology ,0105 earth and related environmental sciences - Abstract
This paper provides information on the structure, chemical composition, and concentrations of microelements in ferromanganese crusts and siliceous crusts sampled on the Pervenets Rise, Sea of Japan. The crusts were formed by cementation of small fragments of green clays (celadonite) by manganese hydroxides (todorokite and birnessite) or by silica. The primary process involved the generation of celadonite, which was deposited as ore-bearing hydrothermal brine that was discharged in the caldera of the volcano or on its slopes. The crusts have a structure that indicates their formation during diffuse percolation of gas-charged hydrothermal brine along fissures or weakened zones in volcanic rocks and subsequent cementation of the resulting celadonite deposits with manganese or siliceous oxides. The manganese and the siliceous mineralization are separated over time, as well as, frequently, in space, and are more local.
- Published
- 2019
30. CONSERVATION OF THE FLOWERS CANVAS PAINTING (1) AT THE EGYPTIAN AGRICULTURAL MUSEUM
- Author
-
Yosr Elsayed
- Subjects
Archeology ,Painting ,Materials science ,food.ingredient ,Zincite ,Metallurgy ,Conservation ,Animal glue ,Carbon black ,Management, Monitoring, Policy and Law ,Hematite ,engineering.material ,Poppy seed ,food ,visual_art ,visual_art.visual_art_medium ,engineering ,Celadonite ,Lazurite - Abstract
The present study aims to examine and treat the flowers canvas painting at the Egyptian Agric-ultural Museum. It is divided into three parts: a) USBDM, SEM-EDX, XRD, GC and FTIR studies, which revealed that the object is suffering from deterioration forms, e.g. ruptures, dust, cracks, missing parts, brittleness, fragility, acidified canvas, and incompatible treatments. The coloring materials are: The green is celadonite (K(Ca, Mg, Fe2) (Fe3Al) [Si4O10](OH)2), the red is hematite (Fe2O3), the blue is lazurite (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2), the beige is hematite (Fe2O3) mixed with barite (BaSO4) and zincite (ZnO), and the gray is carbon black (C). Additionally the ground layer consists of hydrocerussite PbCO3.(OH)2, cerussite Pb3CO3 and zincite ZnO binded with animal glue. The oil media is the poppy seed oil. b) The experimental part showed that 7% Beva371 in toluene is more suitable than the fish glue for object consolidation. c) The applied part covered cleaning, consolidation, patching, lining, completing the missing parts in the painting and ground layers and varnishing.
- Published
- 2019
31. Variability of amethyst mining waste: A mineralogical and geochemical approach to evaluate the potential use in agriculture
- Author
-
Laurent Caner, Edson Campanhola Bortoluzzi, and Jackson Korchagin
- Subjects
Basalt ,Mineral ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Strategy and Management ,05 social sciences ,Geochemistry ,02 engineering and technology ,Amethyst ,engineering.material ,Industrial and Manufacturing Engineering ,Hydrothermal circulation ,Petrography ,Geode ,050501 criminology ,0202 electrical engineering, electronic engineering, information engineering ,engineering ,Celadonite ,Clay minerals ,Geology ,0505 law ,General Environmental Science - Abstract
Large amounts of stone wastes are accumulated alongside different exploiting mines of amethyst geodes in south Brazil, which are becoming an unsustainable environmental issue. For an adequate use of hydrothermal basalt in agriculture as soil remineralizer, it is fundamental to know the material's mineralogy and geochemical variability. This study aims to evaluate the mineralogical and geochemical variability of the basalt from five mines at two positions (near and far from the geodes) in different size fractions to discuss their potential use in agriculture. X-ray diffraction (XRD), X-ray fluorescence (XRF) and petrographic analyses of thin sections were used. Petrographic and mineralogical analyses showed similar compositions for the rocks, consisting of plagioclases, pyroxenes, and opaque minerals with apatite as an accessory mineral. The rock samples located near the amethyst geodes presented slightly higher clay mineral contents than the distant ones. The clay mineralogy was composed of smectite and celadonite. The subfractions preserved the characteristics of the original material. Small geochemical and mineralogical variations were observed in the hydrothermal basalts regardless of the positions and the fraction sizes studied. These characteristics confer this material a high potential for use in agriculture as a soil remineralizer. This approach contributes both to solving an environmental issue associated with geode exploitation and to create an alternative for soil fertilization.
- Published
- 2019
32. Unraveling the materials and techniques of post-Byzantine wall paintings: Is there a sole pictorial phase at the catholicon of Stomion, Central Greece?
- Author
-
Vassiliki Touli, Dimitra Patsiaoura, Triantafyllia T. Zorba, Pavlos Beinas, Ioannis Karapanagiotis, Konstantinos Chrissafis, Dimitrios Lampakis, Lamprini Malletzidou, Eleni Pavlidou, and Konstantinos M. Paraskevopoulos
- Subjects
Painting ,Massicot ,Chemistry ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Archaeology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Analytical Chemistry ,Cinnabar ,engineering ,Celadonite ,0210 nano-technology ,Fresco ,Umber ,Instrumentation ,Spectroscopy ,Byzantine architecture - Abstract
Saint Demetrius of Stomion is a historical monastery placed in the geographical area of Larissa town, Greece, with a remarkable presence from its founding until nowadays. The monastery's present catholicon (main church) has been dated in the 16th century and its surviving wall paintings were constructed in 1758. In addition to the characterization of the materials applied, the purpose of this study is to determine the existence of a sole pictorial phase, that of the mid-18th century, or the occurrence of overpaintings. Additionally, the present study aims to begin the establishment of the documentation of materials and techniques of the late post-Byzantine iconographic guilds, which acted in Central and Northern Greece. The collected samples were analyzed by means of microscopic, spectroscopic and thermogravimetric methods. The use of fresco technique is implied by the major participation of calcium carbonate in all of the painting layers, its main contribution in the plaster layers and the microstratigraphic analysis of the samples' cross-sections, while the scarce and local presence of a proteinaceous material implies the limited use of egg-tempera technique for the highlights. The pigment analysis shows that mostly traditional pigments were used, including cinnabar, ferrous pigments (ochre, sienna, umber), minium, Naples yellow, massicot/litharge, green earth (celadonite), malachite, carbon and bone black, calcite, kaolinite and lead white. The absence of modern pigments, the consistency of all samples regarding microstratigraphy and applied materials, and the lack of the extensive use of an organic medium, strongly suggest the lack of overpaintings.
- Published
- 2019
33. Identification of iron in Earth analogues of Martian phyllosilicates using visible reflectance spectroscopy: Spectral derivatives and color parameters
- Author
-
Joseph R. Michalski, Javier Cuadros, Manuel Melgosa, M. Sánchez-Marañón, and Vesselin Dekov
- Subjects
Materials science ,010504 meteorology & atmospheric sciences ,Analytical chemistry ,Geology ,Nontronite ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Spectral line ,Geochemistry and Petrology ,engineering ,Celadonite ,Saponite ,Spectral resolution ,Clay minerals ,Absorption (electromagnetic radiation) ,Spectroscopy ,0105 earth and related environmental sciences - Abstract
A range of phyllosilicate compositions have been detected spectroscopically on Mars, but the largest fraction by far corresponds to clay minerals rich in Fe and Mg. Given that most of our understanding of Martian clays comes from remote sensing data, it is critically important to explore the details of how compositional variation affects spectral features of phyllosilicates. The greatest efforts have focused so far on near-infrared (NIR) spectroscopy. Recently, ambiguities have been detected in the NIR spectra of 2:1 phyllosilicates with intermediate Fe Mg content that preclude mineral and chemical discrimination. Such ambiguities highlight the relevance of exploring the visible spectral range as a complementary tool to characterize Martian phyllosilicates precisely. This article reports the investigation of laboratory reflectance spectra (330–800 nm) from 34 Earth analogues of Martian phyllosilicates with a wide range of Mg Fe composition, including nontronite, celadonite and saponite end-members, as well as interstratified glauconite-nontronite, talc-nontronite, and talc-saponite. The spectra indicated the presence of Fe(III) by absorption modulations and a decrease in total reflectance, especially in samples with tetrahedral Fe(III). Absorption bands at 370 and 420 nm were diagnostic of octahedrically and tetrahedrally coordinated Fe(III), respectively. Band amplitudes in the second derivative of the Kubelka-Munk function correlated positively with Fe(III) content (R2 > 0.8). Standard color analyses of the visible reflectance spectra under the CIE illuminant D65 indicated that the CIELAB color parameter a*10 was positively correlated with tetrahedral Fe(III), b*10 was positively correlated with octahedral Fe(III), and L*10 was negatively correlated with Fe(III) in both structural sites. Because Fe(II) was in relatively low amount, it did not provide clear spectral evidence. Multiple regression models using the amplitude of the diagnostic absorption bands predicted well absolute Fe content in the phyllosilicates (R2 = 0.89) and the ratio Fe/(Fe + Mg + Al) (R2 = 0.84). CIELAB color parameters improved the prediction of total Fe (R2 = 0.92) and the ratio Fe/(Fe + Mg + Al) (R2 = 0.93). Application of these analyses to Martian data has challenges set by Fe oxide dust coating and spatial and spectral resolution. However, these results mark an avenue to develop testable tools using visible-wavelength spectral data from both satellite and lander probes to help establishing Fe content and mineral identification of Martian phyllosilicates.
- Published
- 2018
34. Features of Green Pigment Used in the Murals on Yeongsanjeon Located in Tongdo Temple - Focused on Noerok and Atacamite
- Author
-
Min Kim
- Subjects
media_common.quotation_subject ,Malachite ,Art ,engineering.material ,Archaeology ,Pigment ,medicine.anatomical_structure ,Temple ,visual_art ,engineering ,medicine ,visual_art.visual_art_medium ,Celadonite ,Atacamite ,media_common - Published
- 2018
35. Micro-Raman spectroscopy and complementary techniques applied for the analysis of rock art paintings at the archaeological locality La Angostura, lower valley of Chubut River (Patagonia, Argentina)
- Author
-
Celeste Gurín, Marcia Mazzuca, Marta S. Maier, and Julieta Gómez Otero
- Subjects
Archeology ,Painting ,Gypsum ,Anhydrite ,biology ,engineering.material ,Hematite ,biology.organism_classification ,Angostura ,Archaeology ,chemistry.chemical_compound ,chemistry ,Anthropology ,visual_art ,engineering ,visual_art.visual_art_medium ,Celadonite ,Rock art ,Glauconite ,Geology - Abstract
In this paper, we characterized for the first time the painting materials in rock art panels of the Patagonian archaeological locality La Angostura using a methodological approach that combined micro-Raman spectroscopy, attenuated total reflection Fourier Transform infrared spectroscopy, and X-ray fluorescence spectroscopy. In this way, we obtained detailed information on the red, green, and black pigments as well as on accessory minerals present in the paints. Hematite was the chromophore in the red paintings while celadonite and glauconite were identified in the green motifs. A manganese oxide, presumably pyrolusite, was characterized as the black pigment. The pigment compositions were also compared to those of natural sediments collected along the valley of the Chubut River, but the components of the red and green sediment samples differed from those present in the rock art paints. In the red motifs of two of the rock art panels, a relevant finding was the presence of gypsum and anhydrite as a priming layer of the corrugated rock support onto which the red paints were applied. This revealed a different painting technique in comparison to that at the other analyzed panels of La Angostura where paints were applied as thin layers on a smooth surface of the rock support. As far as we know, this is the first report on the identification of gypsum and anhydrite as components of a preparation layer in Patagonian rock art. This result contributes to the open discussion on the origin and function of calcium sulfate in rock art.
- Published
- 2021
36. The pressure–temperature–time–deformation history of the Beni Mzala unit (Upper Sebtides, Rif belt, Morocco): Refining the Alpine tectono-metamorphic evolution of the Alboran Domain of the western Mediterranean
- Author
-
Federico Rossetti, Patrick Monié, Mohamed L. Bouybaouene, Sara Marrone, Federico Lucci, Mohamed Najib Zaghloul, Thomas Theye, Università degli Studi Roma Tre, Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Institut für Anorganische Chemie, Universität Stuttgart [Stuttgart], Département de Géologie, Université Mohammed V de Rabat [Agdal], Université Abdelmalek Essaadi (UAE), Marrone, S., Monie, P., Rossetti, F., Lucci, F., Theye, T., Bouybaouene, M. L., and Zaghloul, M. N.
- Subjects
Recrystallization (geology) ,010504 meteorology & atmospheric sciences ,Metamorphic rock ,Geochemistry ,tectono -metamorphic evolution ,Metamorphism ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Nappe ,Geochemistry and Petrology ,Alpine orogeny ,Mediterranean region ,Ar-Ar geochronology ,0105 earth and related environmental sciences ,[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics ,Ar–Ar geochronology ,Geology ,Subduction zone metamorphism ,Andalusite ,Alboran Domain ,Alboran domain ,engineering ,Celadonite ,tectono-metamorphic evolution - Abstract
International audience; The structural and thermal relaxation overprint associated with the Neogene Alboran rifting have obscured the early Alpine tectono‐metamorphic evolution of the Alboran Domain, representing the metamorphic core of the Betic–Rif orogen of the western Mediterranean region. This study focuses on the Beni Mzala unit, forming the lower and deeper structural level of the Alpine metamorphic nappe stack (Upper Sebtides) in the Moroccan Rif. Meso‐ and micro‐scale structural investigations are carried out on high‐P aluminum silicate (Ky‐bearing)‐quartz segregations that occur as boudins within the main retrogressive syn‐greenschist foliation (S2/D2) and assumed to preserve the early M1 HP metamorphism associated with the Alpine orogenic construction in the Alboran Domain. These boudins host an early crenulated high‐P foliation (S1, D1/M1) made of quartz–kyanite–white mica–rutile. A large spread in white mica composition is documented, with the highest Si content per formula unit (up to 3.18 apfu) preserved along the S1 foliation and the lower Si content observed in the white mica marking the S2 retrogressive foliation (D2/M2) and the rim of S1 mica. Microtextural evidence documents post‐tectonic andalusite growth and static recrystallization of the quartz microlithons. Inverse (Zr‐in‐Rt thermometry) and forward modelling thermobarometry are integrated with Ar–Ar white mica geochronology to define the peak and exhumation pressure–temperature–time (P–T–t) path of the Beni Mzala unit. Minimum thermo‐baric estimates for the M1 event are ~1.4 GPa and 600°C, corresponding to a metamorphic gradient of ~11°/km, consistent with subduction zone metamorphism. Exhumation is constrained by re‐equilibration of the white mica composition (from high to low celadonite) between c. 29 and 22 Ma, during a nearly isothermal retrogressive path, with final equilibration at high‐T/low‐P conditions within the andalusite stability field (~0.2–0.3 GPa and 500°C). A minimum late Oligocene age is proposed for the Alpine D1 tectono‐metamorphic stage in the Rif, suggesting as feasible the previously proposed Eocene timing for the subduction‐zone metamorphism of the Alboran Domain. Conclusive evidence is provided to link the early Miocene tectono‐metamorphic event to a late thermal perturbation that affected the Alboran Domain at shallow crustal conditions, post‐dating the almost complete exhumation of the deep roots of the Alpine belt in the western Mediterranean.
- Published
- 2021
37. Exhumation dynamics of high‑pressure metamorphic rocks from the Voltri Unit, Western Alps: constraints from phengite Rb–Sr geochronology
- Author
-
Paul G. Starr, Laura Federico, Andrew J. Smye, Marco Scambelluri, and Spencer Mark Seman
- Subjects
geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Subduction ,Metamorphic rock ,Bedrock ,Geochemistry ,Metamorphism ,engineering.material ,Eclogite · Subduction · Rb–Sr geochronology · Phengite · Exhumation · Alps ,010502 geochemistry & geophysics ,01 natural sciences ,Phengite ,Geophysics ,Geochemistry and Petrology ,Geochronology ,engineering ,Celadonite ,Eclogite ,Geology ,0105 earth and related environmental sciences - Abstract
The Voltri Unit and adjacent Tertiary Piedmont Basin, Western Alps, preserve complementary bedrock and sedimentary archives of Alpine subduction and exhumation. Combined PT modeling and phengite Rb–Sr geochronology of bedrock and clast samples shows that Fe–Ti metagabbros and metasediments preserve a record of protracted high-pressure metamorphism, between ~ 50 and ~ 40 Ma. Bedrock and clast Fe–Ti metagabbros yield similar eclogite-facies peak conditions, between 23 and 25 kbar, 510–530 °C; phengite, zoned in celadonite content, with cores > 3.5 Si c.p.f.u. and rims 10 Myr until subduction ceased on arrival of the European continent into the orogenic wedge. As shear tractions on the plate interface are considered to exceed available buoyancy forces for exhumation, we suggest that syn-subduction exhumation occurred along the wedge-plate interface.
- Published
- 2021
38. Green earth pigments dispersions: Water dynamics at the interfaces
- Author
-
Pierre Levitz, Jean-Pierre Korb, Maguy Jaber, Laurent J. Michot, Agathe Fanost, Guillaume Mériguet, Anne-Laure Rollet, Laurence de Viguerie, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Archéologie Moléculaire et Structurale (LAMS)
- Subjects
Relaxometry ,Materials science ,Field (physics) ,[SDV]Life Sciences [q-bio] ,Water surface interaction ,02 engineering and technology ,engineering.material ,010402 general chemistry ,01 natural sciences ,Biomaterials ,Diffusion ,Paramagnetism ,Colloid and Surface Chemistry ,Celadonite ,Phyllosilicate ,Glauconite ,Diffusion (business) ,021001 nanoscience & nanotechnology ,Fast Field Cycling NMR relaxometry ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Chemical physics ,engineering ,0210 nano-technology ,Dispersion (chemistry) ,Earth (classical element) - Abstract
International audience; Hypothesis: The objective is to elucidate the multiscale dynamics of water within natural mixtures of minerals, green earth pigments that are mainly composed of phyllosilicates containing large amount of iron. In particular, the interaction of water with the different kinds of surfaces has to be probed. One issue is to examine the influence of surface type, basal or edge, on the dispersion quality.Experiment: The study was carried out using 1H variable field NMR relaxometry on various green earth pigment dispersions and concentrations. To analyse the data, a new analytical model was developed for natural phyllosilicates containing large amount of paramagnetic centres.Finding: The proposed theoretical framework is able to fit the experimental data for various samples using few parameters. It allows to determining water diffusion and residence times in complex phyllosilicate dispersions. Furthermore, it makes it possible to differentiate the contribution of the basal and edge surfaces and their respective surface area in interaction with water. Moreover, NMR relaxation profile reveals to be highly sensitive to the structural aspect of the phyllosilicates and to the accessibility of water to iron, hence allowing to discriminate clearly between two very similar phyllosilicates (glauconite and celadonite) that are difficult to distinguish by standard structural methods.
- Published
- 2021
39. Single mineral particle makes an electron point source.
- Author
-
Salançon, Evelyne, Daineche, Rachid, Grauby, Olivier, and Morin, Roger
- Subjects
ELECTRON emission ,CELADONITE ,KAOLINITE ,CARBON films ,CARBON fibers - Abstract
A mineral (celadonite, kaolinite) nanometer-thick particle deposited on a flat carbon film or at the apex of a carbon fiber provides electron emission at low applied fields. Voltage and time dependences of the emission intensity are studied, and a model of the underlying mechanism is proposed. An electron point source providing emission from a single particle is built and characterized. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
40. celadonite
- Author
-
Herrmann, Helmut and Bucksch, Herbert
- Published
- 2014
- Full Text
- View/download PDF
41. Mg-Phengite in Carbonate Rock Syngenetically Formed from Hydrothermal Fluid: Micro-Textural Evidence and Mineral Chemistry
- Author
-
Nam Soo Kim, Yungoo Song, Chaewon Park, and Sung Ja Choi
- Subjects
Dolostone ,lcsh:Mineralogy ,lcsh:QE351-399.2 ,010504 meteorology & atmospheric sciences ,Chemistry ,Muscovite ,Analytical chemistry ,Geology ,Mg-phengite ,Authigenic ,engineering.material ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,infiltration ,01 natural sciences ,Hydrothermal circulation ,Phengite ,Diagenesis ,engineering ,Celadonite ,Carbonate rock ,Haengmae Formation ,muscovite–celadonite solid solution ,0105 earth and related environmental sciences - Abstract
Phengite series is a dioctahedral solid solution between two end-members of muscovite [K1[Al2]VI[Al1,Si3]IVO10(OH)2] and celadonite [K1[(Fe3+,Al)1,(Mg,Fe2+)1]VI[Si4]IVO10(OH)2], which have a hetero-valent substitution of AlVIAlIV &harr, (Mg, Fe)VISiIV. In this study, we report a hydrothermal-originated authigenic Mg-phengite-series mineral, which occurred as polycrystalline aggregates (Type 1), pore-fillings (Type 2) and well-crystallized lath form (Type 3) from the Haengmae Formation, a dolomite&ndash, pebble-bearing fine sand-sized dolostone, in South Korea. Based on micro-textural observation, three types of Mg-phengite are associated with crystalline dolomite, and are followed by calcite precipitation as pore-filling, indicating that these should be formed by the influx of a Mg-rich hydrothermal fluid after the deposition of some clastic sediments and before calcite-filling. The structural formula based on O10(OH)2 shows that the number of Mg atoms per formula unit (apfu) of Mg-phengite ranges from 0.00 to 0.70 with no Fe, which is relatively high, compared with the previously reported metamorphic phengites. In REEs mineral chemistry, the Mg-phengites are characterized by the enrichment of REEs and by the particular enrichment of LREEs in the polycrystalline aggregates of Mg-phengite. It strongly suggests that the Mg-phengite should be formed by the infiltration of the highly evolved Mg- and REEs-enriched hydrothermal fluid into the clastic sedimentary rock (Haengmae Formation) as a strata-bound form, syngenetically or during early diagenesis.
- Published
- 2020
- Full Text
- View/download PDF
42. Biosignatures in Subsurface Filamentous Fabrics (SFF) from the Deccan Volcanic Province, India
- Author
-
Tomasz Machałowski, Teofil Jesionowski, Beda Hofmann, Berthold Ottens, Reinhard Kleeberg, Jens Götze, Hermann Ehrlich, and Mikhail V. Tsurkan
- Subjects
Mineralization (geology) ,lcsh:QE351-399.2 ,010504 meteorology & atmospheric sciences ,Chalcedony ,Lava ,smectites ,Geochemistry ,zeolites ,macromolecular substances ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,subsurface filamentous fabrics ,Deccan Volcanic Province ,parasitic diseases ,550 Earth sciences & geology ,silica minerals ,Quartz ,Chemical composition ,0105 earth and related environmental sciences ,Basalt ,lcsh:Mineralogy ,Chemistry ,technology, industry, and agriculture ,Geology ,500 Science ,Geotechnical Engineering and Engineering Geology ,biomineralization ,engineering ,Celadonite ,biosignatures ,Biomineralization - Abstract
The morphology, chemical, and mineralogical composition of subsurface filamentous fabrics (SFF) from the Deccan Volcanic Province (DVP) were investigated to determine the origin of these spectacular aggregates. SFF occur in a wide variety of morphologies ranging from pseudo-stalactites to irregular fabrics and are classified as SFFIr (irregular) or SFFMa (matted). The SFF samples exhibit a thread-like (or filament-like) center from which mineral precipitation starts to form the final macroscopic morphologies. Detailed investigations revealed organic material (fungal chitin) in the innermost filamentous core, which may have acted as an initial nucleus for the mineralization processes. The morphometric characteristics of certain filamentous fabrics are very similar to those of microbial filaments and the fabrics formed from them but are clearly distinct from similar types of non-biological precipitates (fibrous minerals, speleothems, and &ldquo, chemical gardens&rdquo, ). These features indicate that the filamentous cores might be products of microbial communities that were active in the basaltic cavities. The SFF cross-sections display similar concentric layers of the mineral succession and reach thicknesses of several centimeters with spectacular lengths up to 100 cm and constant diameters. The typical mineralization sequence points to temporal variation in the chemical composition of the mineralizing fluids from Fe(Mg)-rich (Fe-oxides/-hydroxides, Fe-rich sheet silicates such as celadonite and di-/tri-smectite) to Ca-dominated (Ca-rich zeolites) and finally pure SiO2 (opal-CT, chalcedony, and macro-crystalline quartz). Assuming biological activity at least during the early mineralization processes, circumneutral pH conditions and maximum temperatures of 100&ndash, 120 °, C were supposed. The formation of filamentous cores including Fe-bearing phyllosilicates probably occurred near the surface after cooling of the lava, where the elements necessary for mineral formation (i.e., Si, Mg, Al, Fe) were released during alteration of the volcanic host rocks by percolating fluids.
- Published
- 2020
43. Chemical-technological research and radiocarbon AMS dating of wall painting fragments from the ruins of the XIIth-XIIIth centuries AD church from archaeological excavations in the city of Smolensk, Russia
- Author
-
Mariya Kabanova and Konstantin Voronin
- Subjects
010506 paleontology ,Archeology ,lcsh:Fine Arts ,XRD ,lcsh:Analytical chemistry ,Conservation ,engineering.material ,Church ,01 natural sciences ,Russia ,law.invention ,XIIth-XIIIth century AD ,Technological research ,Archaeological research ,law ,Narrow range ,AMS radiocarbon dating ,Radiocarbon dating ,0105 earth and related environmental sciences ,Painting ,lcsh:QD71-142 ,010401 analytical chemistry ,Excavation ,Archaeology ,Wall paintings ,0104 chemical sciences ,Foundation (cosmetics) ,engineering ,Celadonite ,lcsh:N - Abstract
In 2012, the ruins of a temple of the old Russian period were found during archaeological research in the medieval historical territory of Smolensk. The archaeological complex consists of the ruins of an ancient temple, built in the middle of the XIIth century AD, and adjacent to it from the South-West of the territory, which housed the remains of the market XI-turn XIII-XIV centuries AD and necropolis XIII–XVI centuries AD. Chronologically diverse use of the investigated territory up to the XVIth century AD was determined by the nearby Church. Approximately 1000 fragments of wall paintings, 5 fragments window glass and 4 glazed floor tiles were found near the ruins of the Church building. For the first time fragments of wall paintings medieval of Old Russian temple were dated by the AMS radiocarbon dating and went through chemical-technological research (analysis of the plaster foundation, the definition of used pigments) by X-RAY diffractometry (XRD) and scanning electron microscopy (SEM/EDS). Optical microscopy also was used for visual observations of the samples of the wall painting. According to the results of the radiocarbon analysis, the fragments of the wall paintings were divided into two chronological groups. The earlier belongs to the last quarter of the XIIth–the first quarter of the XIIIth century AD. Samples of the wall paintings from the second group are dated back to the third quarter of the XIIIth century AD. A narrow range of Accelerator Mass Spectrometry (AMS) radiocarbon dating of fragments of the murals, obtained from carbonates due to the presence of high content of C14 isotope in carbon of the plaster, is simultaneous in age to the moment of creation of the plaster base. As a result of chemical and technological researches of the fragments of the wall paintings it was established that the plaster basis of the fragments of the wall painting consists of two layers. The plaster base contains organic binders. Chemical and technological analysis of pigments presents the following results: (1) the basis of the blue paint layer is ultramarine (mineral) and anatase (mineral); (2) the basis of the green paint layer is celadonite (mineral); (3) the basis of the brown paint layer is ochre (clay); (4) black particles in the colorful mixture of brown is an organic wood coal pigment.
- Published
- 2020
44. Deciphering the metamorphic evolution of the Pulo do Lobo metasedimentary domain (SW Iberian Variscides)
- Author
-
Irene Pérez-Cáceres, Olivier Vidal, Olivier Beyssac, Antonio Azor, Franck Bourdelle, David Martínez Poyatos, José Fernando Simancas, Fernando Nieto, Ministerio de Ciencia e Innovación (España), Ministerio de Economía y Competitividad (España), Junta de Andalucía, Universidad de Granada (UGR), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Génie Civil et Géo-Environnement [Béthune] (LGCgE), Université d'Artois (UA), and Universidad de Granada = University of Granada (UGR)
- Subjects
Accretionary wedge ,010504 meteorology & atmospheric sciences ,High-pressure ,Greenschist ,Stratigraphy ,Metamorphic rock ,Geochemistry ,Soil Science ,Metamorphism ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,South portuguese zone ,U-PB ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Crenulation ,lcsh:Stratigraphy ,Geochemistry and Petrology ,Carboniferous ,White-mica crystallinity ,Tectonic Evolution ,Low-Grade Metamorphism ,0105 earth and related environmental sciences ,Earth-Surface Processes ,lcsh:QE640-699 ,lcsh:QE1-996.5 ,Paleontology ,P-T constraints ,Geology ,Rheic Ocean ,Shear zones ,lcsh:Geology ,Geophysics ,engineering ,Celadonite ,Shear zone ,Ossa-Morena zone - Abstract
The Pulo do Lobo domain is one of the units exposed within the orogenic suture zone between the Ossa-Morena and the South Portuguese zones in the SW Iberian Variscides. This metasedimentary unit has been classically interpreted as a Rheic subduction-related accretionary prism formed during pre-Carboniferous convergence and eventual collision between the South Portuguese Zone (part of Avalonia) and the Ossa-Morena Zone (peri-Gondwanan terrane). Discrete mafic intrusions also occur within the dominant Pulo do Lobo metapelites, related to an intra-orogenic Mississippian transtensional and magmatic event that had a significant thermal input. Three different approaches have been applied to the Devonian-Carboniferous phyllites and slates of the Pulo do Lobo domain in order to study their poorly known low-grade metamorphic evolution. X-ray diffraction (XRD) was used to identify the mineralogy and measure crystallographic parameters (illite "crystallinity" and K-white mica b-cell dimension). Compositional maps of selected samples were obtained from electron probe micro-analysis, which allowed for processing with XMapTools software, and chlorite semiempirical and thermodynamic geothermometry was performed. Thermometry based on Raman spectroscopy of carbonaceous material (RSCM) was used to obtain peak temperatures. The microstructural study shows the existence of two phyllosilicate growth events in the chlorite zone, the main one (M-1) related to the development of a Devonian foliation S-1 and a minor one (M-2) associated with a crenulation cleavage (S-2) developed in middle-upper Carboniferous times. M-1 entered well into epizone (greenschist facies) conditions. M-2 conditions were at lower temperature, reaching the anchizone-epizone boundary. These data accord well with the angular unconformity that separates the Devonian and Carboniferous formations of the Pulo do Lobo domain. The varied results obtained by the different approaches followed, combined with microstructural analysis, provide different snapshots of the metamorphic history. Thus, RSCM temperatures are higher in comparison with the other methods applied, which is interpreted to reflect a faster re-equilibration during the short-lived thermal Mississippian event. Regarding the metamorphic pressure, the data are very homogeneous: very low celadonite content (0 %-10 %) in muscovite (and low values of K-white mica b-cell dimension; 8.995 angstrom mean value), indicating a low pressure-temperature gradient, which is unexpected in a subduction-related accretionary prism., This research has been supported by the Spanish Ministry of Science and Innovation (grant no. CGL2011-24101), the Spanish Ministry of Economy and Competitiveness (grant nos. CGL2015-71692-P, CGL2016-75679-P), the Andalusian Government (grant nos. RNM-148, RNM-179), and the doctoral scholarship to Irene Perez-Caceres from the Spanish Ministry of Science and Innovation (grant no. BES-2012-055754). The Raman facility in Paris has been funded by the city of Paris (Emergence program).
- Published
- 2020
45. Mineralogical and Geochemical Study of the Zeolitized Volcaniclastic Rocks of Petrota region, Evros Prefecture, Northeastern Greece
- Author
-
Michael Vavelidis, Nikolaos Kantiranis, Eleni Michailidou, and Lambrini Papadopoulou
- Subjects
Clinoptilolite ,010504 meteorology & atmospheric sciences ,Volcaniclastic rocks ,Zeolitization ,Geochemistry ,Pyroxene ,engineering.material ,010502 geochemistry & geophysics ,Sanidine ,01 natural sciences ,Evros ,Rhyolite ,Titanite ,Petrota ,Materials Chemistry ,engineering ,Celadonite ,Phenocryst ,Plagioclase ,Argillic alteration ,Amphibole ,Geology ,0105 earth and related environmental sciences - Abstract
The present work studies the tuffs associated with the volcanic area of the Paleogene Sheinovets caldera, located on the southeastern part of the Rhodope massif, in Bulgaria. Its purpose is to describe the mineralogical and geochemical composition of the zeolitized volcaniclastic deposits in the broader area of Petrota village, in the northwesternmost part of the Greek regional unit of Evros, in northeast Greece. The samples studied in this work were collected from seven (7) different locations, covering an area of almost 4 km in length and 2 km in width. Macroscopically, the samples display a greyish-green hue and they are widespread in the area of study. They often contain fragments of the crystalline metamorphic basement (mica-schists, phyllites, amphibolites, quartzites) and/or rhyolitic clasts. A rhyolitic outcrop of greyish-pink hue is observed in the Mavri Petra region, probably related to the Rupelian acid volcanism that occurred in the Sheinovets caldera. The mineralogy of the tuffs was studied under light polarizing microscope and using Scanning Electron Microscopy (SEM), and it was further confirmed by X-ray powder diffraction (XRPD) method. The initial matrix of the tuffs consisted predominantly of glass shards that are now partly or fully altered into zeolites and clay minerals, such as celadonite, displaying characteristic pseudomorphic structures. The dominant zeolite is clinoptilolite, while in some areas the presence of mordenite is also noticed. Feldspar phenocrysts are abundant, and they are represented by plagioclase and sanidine. Although quartz crystals can be observed under light-polarizing microscope solely in metamorphic fragments, the presence of silica polymorphs was also confirmed through SEM and XRPD analysis, with quartz and cristobalite prevailing. The mineralogical assemblage includes phenocrysts of biotite and in some cases amphiboles, while pyroxene, epidote, garnet, titanite, apatite, zircon, ilmenite, magnetite and rutile are additional minerals which have been identified locally in accessory quantities. Chemical analysis was carried out for major and trace elements, using the X-ray fluorescence (XRF) method and 4 Acid digestion ICP-MS analysis, respectively. The samples of Mavri Petra region, exhibit high concentrations in Cu, Pb, Mn, V, P and W. The analyzed concentrations of U in the area of Palaeokklisi are relatively high in comparison to the rest due to its proximity to a fault. Towards the northwestern study area, close to the Greek-Bulgarian border, the concentrations of Sr appear to be particularly high, probably because the area is closer to the volcanic centre.
- Published
- 2020
46. Agates from Western Atlas (Morocco)—Constraints from Mineralogical and Microtextural Characteristics
- Author
-
Tomasz Toboła, Dominika Skrepnicka, Jaroslav Pršek, Magdalena Dumańska-Słowik, Damian Zych, Lucyna Natkaniec-Nowak, and Tomasz Powolny
- Subjects
Recrystallization (geology) ,lcsh:QE351-399.2 ,010504 meteorology & atmospheric sciences ,Chalcedony ,moganite ,Geochemistry ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Hydrothermal circulation ,ore minerals ,chemistry.chemical_compound ,Moroccan agates ,Quartz ,0105 earth and related environmental sciences ,Calcite ,lcsh:Mineralogy ,microtexture ,Geology ,Geotechnical Engineering and Engineering Geology ,chemistry ,engineering ,Celadonite ,Raman spectra ,Vein (geology) ,Moganite - Abstract
Agate samples collected from the vicinity of Asni and Agouim (Western Atlas, Morocco) were investigated using microscopic observations supported by Raman micro-spectroscopy. The agates are marked by the presence of various microtextures typical of epithermal vein deposits, including jigsaw-puzzle, feathery, and lattice-bladed. The first two indicate that the formation of agates was likely marked by recrystallization of metastable silica phases (i.e., opaline silica or massive chalcedony). The presence of lattice-bladed (after barite and calcite) quartz may be, in turn, ascribed to the boiling-related conditions that could have triggered the formation of abundant copper and iron sulfides found within silica matrix. Additionally, the local occurrence of growth lines (so-called Bambauer quartz) and intergrowth of length-slow and length-fast chalcedony are linked to the variations of physico-chemical conditions during rock formation (alkaline-acidic). According to Raman spectroscopy, silica matrix of the agates is made of &alpha, quartz with a local admixture of moganite (from 0.0 up to 78 wt.%), but also contains numerous solid inclusions of hematite, celadonite, as well as poorly-organized carbonaceous material and rutile. These phases were likely emplaced during low-temperature hydrothermal activity of SiO2-bearing fluids that originated from post-magmatic hydrothermal activity developed within host rocks and/or meteoric waters.
- Published
- 2020
- Full Text
- View/download PDF
47. Connoisseur's Choice: Muscovite, Shannon Canyon, Inyo County, California.
- Author
-
Pohwat, PaulW.
- Subjects
- *
MUSCOVITE , *CELADONITE , *IGNEOUS rocks , *TUNGSTEN , *STEAM generators , *FURNACES , *GRANITE - Abstract
The article provides information on the aesthetic backgrounds of muscovite. It says that muscovite forms a continuous series with celadonite and aluminoceladonaite, and it can be used as a substitute for window glass, particularly in ovens and furnaces. It notes that the muscovite specimens are found in tin-tungsten deposits and is a constituent of granite, gnesis and phyllites.
- Published
- 2013
- Full Text
- View/download PDF
48. Effects of internal gradients on pore-size distribution in shale
- Author
-
Jack C. Pashin and Christian Obasi
- Subjects
Chamosite ,010504 meteorology & atmospheric sciences ,Energy Engineering and Power Technology ,Mineralogy ,Geology ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Magnetic susceptibility ,Paramagnetism ,chemistry.chemical_compound ,Fuel Technology ,Montmorillonite ,chemistry ,Geochemistry and Petrology ,Illite ,Earth and Planetary Sciences (miscellaneous) ,engineering ,Kaolinite ,Celadonite ,Clay minerals ,0105 earth and related environmental sciences - Abstract
In porous media, effects of internal gradient caused by magnetic susceptibility contrast between the matrix and infilling fluid shifts transverse relaxation time (T2) to shorter time, resulting in imprecise classification of pore sizes. In shale, details of the effects of paramagnetic and clay minerals that induce the internal gradients are poorly understood. We measured a brine mixture with a granular form of minerals, including kaolinite, montmorillonite, glauconite, illite, pyrite, celadonite, and chamosite, to infer contributions of each to T2 relaxation in shale. Nuclear magnetic resonance (NMR) response of these samples was used to calculate the total mean logarithm of T2 (T2ML) and volume of water in the samples. Additionally, physical properties such as magnetic susceptibility, specific surface area, and elemental composition were acquired. Pore geometry, magnitude of internal gradients, pore-size distributions, and secular regimes in which the media relaxed (based on their shortest characteristic time scales) were characterized from these properties. These time scales measure the behavior of the relaxation regimes such as longitudinal relaxation time-to-T2 ratio and dependence of relaxation rate on echo spacing (tE). Glauconite illite, pyrite, chamosite, and kaolinite grouped into a small-pore system, whereas montmorillonite and celadonite grouped into large-pore systems. A free diffusion regime governed secular relaxation for kaolinite; a motional-averaging regime governed montmorillonite, celadonite, and large tE chamosite; whereas a localization regime dominated the rest of the minerals. We conclude that understanding the effects of internal gradients in shale is important to quantify the shortening of T2ML, which leads to overestimation of bulk fluid volume and, thus, underestimating NMR permeability when used as an input into permeability estimator equations.
- Published
- 2018
49. Mineralogy and geochemistry of various colored boles from the Deccan volcanic province: Implications for paleoweathering and paleoenvironmental conditions
- Author
-
D. C. Meshram, Priyeshu Srivastava, Satish J. Sangode, and N. Siva Siddaiah
- Subjects
Basalt ,010504 meteorology & atmospheric sciences ,Geochemistry ,Mineralogy ,Weathering ,Nontronite ,Hematite ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,visual_art ,Subaerial ,visual_art.visual_art_medium ,engineering ,Celadonite ,Clay minerals ,Geology ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Volcanic ash - Abstract
Boles are markers of hiatus in successive eruptions of the Deccan flood volcanism (DFV) emplaced at the Cretaceous-Paleogene boundary that are interpreted to retain paleoenvironmental information from their subaerial exposure. To evaluate paleoenvironment during these hiatuses, mineralogy and geochemistry of three different colors of boles, i.e., red (dark = 10R-3/6 and light = 10R-4/8), brown (5YR-4/4) and green (5G-6/2) were examined. The plagioclase index of alteration (PIA) (loss of Ca and Na relative to Al) was between 76 and 81 for all the boles, indicating moderate chemical weathering that is probably due to their short subaerial exposures. Mass balance calculations show significant enrichments of K, Si, Mg and Rb in green and brown boles suggesting an allochthonous input that is interpreted as volcanic ash fallout. Mineralogically, the red bole is dominated by montmorillonite and hematite, the brown bole of ferruginous smectite and montmorillonite, and the green bole of celadonite and nontronite. Montmorillonite and hematite genesis in red boles indicates leaching in an oxidative environment at near neutral pH (~5.5 to 8) conditions. Further, heating of the altered basalt from emplacement of upper lava flows under subaerial-dry conditions could have also promoted the formation of hematite in red boles. The hydrothermal alteration of K and Mg enriched volcanic ash admixed with the altered lower flow basalt under slightly reducing oxidation potential led to the genesis of nontronite and celadonite in the green bole. The aluminous Fe-smectite in brown bole occurred from hydrothermal alteration of aluminous clays (e.g., montmorillonite). The different colored boles, therefore, suggest a range of weathering processes including chemical leaching to hydrothermal alteration in oxidative to reducing environmental conditions throughout DFV emplacement that could reflect changing surficial conditions associated with volcanically forced changes to the environment.
- Published
- 2018
50. Occurrence and Mineralogical Properties of Green-Blue Inorganic Pigments in Korea
- Author
-
Hyen Goo Cho, Jin Young Do, and Gi Young Jeong
- Subjects
Mineral ,010504 meteorology & atmospheric sciences ,Azurite ,chemistry.chemical_element ,Malachite ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Copper ,Pigment ,chemistry ,visual_art ,Environmental chemistry ,Inorganic pigments ,visual_art.visual_art_medium ,engineering ,Celadonite ,Glauconite ,0105 earth and related environmental sciences - Published
- 2018
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.