Identification of Mixed-Layer Mineral of Cambodian Clays and their Phase Changes upon Firing

2012 ◽  
Vol 620 ◽  
pp. 72-76
Author(s):  
Bun Kim Ngun ◽  
Mohamad Hasmaliza ◽  
Kiyoshi Okada ◽  
Phat Bone ◽  
Zainal Arifin Ahmad

Representative of clay deposits from central Cambodia were analyzed in terms of their mineral phases, mineralogical composition and phase changes after firing by qualitative and quantitative XRD analysis. To examine the phase changes, the samples were prepared and fired from 950 to 1200 °C. Results show that Cambodian clays contained quartz, illite, kaolinite, and chlorite-vermiculite mixed-layer as dominant mineral phases and the minor phases of albite and calcite also appeared in the samples. The rational analysis shows that chlorite-vermiculite was the main mineral in all Cambodian clays. After the samples were preceded upon firing, new phases of mullite, hematite and crystobalite were appeared above 1050 °C.

2020 ◽  
Author(s):  
Nikita Churilin ◽  
Marina Lebedeva ◽  
Evgheni Varlamov

<p>Chestnut soils are an obligatory component of solonetz complexes in the northern part of the Caspian lowland, differ from solonetzes by the morphological properties of the horizons, although these soils are usually located at a distance of several meters.</p><p>For the chestnut soil we can see the following vegetation: forbs-fescue-feather association with spirea, sometimes with a thin moss cover. Above the solonetz dominates Kochia prostrata and Artemisia pauciflora with Myosúrus sp. and rare Poa sp. curtains.</p><p>The aim of the study is to identify the mineralogical composition of clay fraction (<1 μm) of chestnut soil and to compare it with the mineralogical composition of the solonetz in the area with unexpressed microrelief.</p><p>To separate soil fractions <1 μm samples were rubbed into a thick paste and sedimented. Oriented preparations of fractions were examined by XRD method.</p><p>The balance of the mineral phases of clay in soils and parent rocks is the same - mixed-layered minerals prevail over illite. An exception is only the upper horizons of the compared soils, in which the content of illite prevails over mixed-layer minerals. In this case, the thickness of the surface horizons differs more significantly (5 times) than the difference in the content of illite in the clay fraction of the solonetz in SEL (0-5 cm) horizon. This soils are also have certain features of similarity in the crystallochemical shape: the imperfection of the kaolinite structure and the superdispersed shape of the mixed-layer phase at the surface horizons, as well as the appearance of individual smectite and chlorite packets in the mixed-layer phase in the lower horizons (BC and C).</p><p>The work was supported by RFBR 18-016-00129-а.</p>


2020 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Hemayatullah Ahmadi ◽  
Atal Yousufi ◽  
Amir Mohammad Mosazai

Sand is a common construction material used for various purposes, e.g., concrete, mortar, render, screed, and asphalt. The usage depends on its fineness, and its fineness is controlled by its mineralogical composition and physical-mechanical properties. This research aims to determine the chemical and mineralogical composition and the physical-mechanical properties of the Dasht-e-Taatrang Zar sand deposits within the Qarabagh and Bagram districts of Kabul and Parwan provinces in Afghanistan. To achieve the objectives of this research, a review of the existing literature has been combined with new extensive field works for macroscopic studies and sample collection, and laboratory analyses. In total, 23 samples during two phases of field works were collected and subjected to lab works for XRF, Schlich, and XRD analysis to determine the chemical and mineralogical composition; moreover, sieve and Atterberg analysis, specific gravity, soundness, and alkali-silica reaction tests were performed for characterization of the physical-mechanical properties of the studied samples. The results of the tests show that the Taatrang Zar sand deposits are considered as a suitable construction material, and due to their simple accessibility, the deposits have high potential as a construction material supplier for the Kabul new city project (Dehsabz) in Kabul and adjacent Parwan and Kapisa provinces.


Author(s):  
Radosław Rogoziński ◽  
Alina Maciejewska

AbstractVarved clay deposits from ice-dammed lakes are a particularly important and broadly applied raw material used for the production of high-quality ceramics (red bricks, roof tiles, etc.), but the mineralogy and geochemistry of these sediments are not fully understood. The aim of the present study was to determine the chemical and mineralogical composition of ice-dammed lake sediments of the Lębork deposit. Major-element analysis of the compositions of selected samples from the ice-dammed lake clays was performed by X-ray fluorescence (XRF) and trace elements were determined by inductively coupled plasma-mass spectrometry. The mineralogical composition of clay samples was determined by X-ray diffraction (XRD). Analyses of the chemical composition of the ice-dammed lake clays of the Lębork deposit showed that the dominant component was SiO2 with a mean content of 56.13 wt.%; the second most abundant component was Al2O3, with a mean content for the entire deposit of 11.61 wt.%. Analysis by ICP-MS indicated the presence of rare earth elements (REE), e.g. cerium, neodymium, lanthanum, and praseodymium; their mean contents are: 56.9, 27.0, 26.3, and 7.3 ppm, respectively. Mineralogical analysis of the varved clays identified quartz, muscovite, calcite, and clay minerals – illite, kaolinite, and montmorillonite. The material filling the Lębork basin is characterized by small lateral and vertical variability in chemical composition. The results of the present study may be of considerable importance in determining the parent igneous, metamorphic, and sedimentary rocks, the weathering products of which supplied material to the ice-dammed lake, as well as in determining the mechanisms and character of the sedimentation process itself.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yasin Erdoğan

Handere clay deposits were discovered at Adana in Turkey. These clay units primarily consist of uncoloured claystone, pebbly sandstone, sandstone, siltstone, and mudstone marl and include gypsum lenses and clay levels of various thicknesses in places. The physicochemical properties of these clays have been investigated by different techniques including Scanning Electron and Elemental Analysis (SEM and EDS), mineralogical analyses, chemical and physical analyses, X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), and Atterberg (Consistency) Limits Test. The mineralogical composition deduced from XRD is wide (smectite + palygorskite + illite ± feldspar ± chlorite ± quartz ± calcite ± serpentine) due to the high smectite contents (≈85%). SEM studies reveal that smectite minerals are composed of irregular platy leaves and show honeycomb pattern in the form of wavy leaves in places. The leaves presenting an array with surface edge contact are usually concentrated in the dissolution voids and fractures of volcanic glass. Organic matter content and loss on ignition analysis of raw materials are good for all the studied samples. In summary, Handere clays can be used as building materials in bricks, roof tiles, and cement and as a binder.


2021 ◽  
Author(s):  
Juliette Debrie ◽  
Dimitri Prêt ◽  
Karim Benzerara ◽  
Jean Paul Saint Martin

<p>Stromatolites, i.e. macroscopically laminated carbonate rocks formed by diverse microbial communities, are particularly emblematic geobiological materials since they are the oldest evidence of life-mineral interactions, dated up to 3.5 Gyrs ago.  They are found throughout the history of the Earth and have received strong attention because they provide precious information about microbial paleobiodiversity and paleoenvironments. However, while this information is interpreted based on our knowledge about modern analogs, the latter remains very incomplete. Here, we studied recently discovered modern stromatolites from Mari Ermi<sup>1</sup>, a coastal pond in Western Sardinia, that seasonally experience severe evaporation and broad salinity variations. For this purpose, we explored the mineralogical composition of these unique sedimentary archives and its spatial variations in order to gain better insight into how mineral phases record the conditions and processes of their formation. We investigated the heterogeneous distribution of minerals using quantitative X-ray chemical maps provided by energy dispersive x-ray spectrometry analyses coupled with scanning electron microscopy (SEM-EDXS). Hyperspectral maps were analyzed using an innovative data treatment method <sup>2</sup> allowing phase recognition within the complex mineral mixtures and solid solutions encountered. This method provided quantitative data on spatial distribution, modal content and associated calculated unit formulas for each identified mineral and phase with a hundred nanometer resolution. Based on these results, we will discuss the origin of the laminations in the stromatolites.</p><p>Reference:</p><p>1. Saint Martin, J.-P. & Saint Martin, S. Geo-Eco-Marina <strong>21</strong>, 35–53 (2015a).</p><p>2. Prêt, D. et al. American Mineralogist <strong>95</strong>, 1379–1388 (2010).</p>


Clay Minerals ◽  
1969 ◽  
Vol 8 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Bibhuti Mukherjee ◽  
M. G. Rao ◽  
C. Karunakaran

The mineral phases and the distribution of major, minor and trace elements in the clays and bed rocks of two bore-holes at Adda and Chaubatta of the Birbhum area have revealed an intimate relationship of the kaolin-rich clays with the bed-rock of Adda. The possibility of a common origin for the clay deposits at Chaubatta, lying close to the Rajmahal trap formations, and at Adda, lying close to the Archaean boundary, has been inferred from trace element distribution and other factors. A genetic relationship of the clay deposit at Adda with the bed-rock, altered Archaean gneiss, has been established, but there is no significant relationship of the Chaubatta clay deposit with its bed-rock, the weathered basalt.The lateritic cappings above the kaolin-rich clays of Adda and Chaubatta areas are explained as being formed from kaolinite in the weathering sequence as the end-product of intensive desilication under conditions of intensive leaching and increasing acidity near the surface.


Clay Minerals ◽  
1994 ◽  
Vol 29 (1) ◽  
pp. 47-61 ◽  
Author(s):  
D. Beaufort ◽  
A. Meunier

AbstractThe clay deposits in fractures of the metamorphic basement under the Paris Basin sedimentary formations at Sancerre-Couy (France) are composed of trioctahedral species which are exceptionally well crystallized. Three samples were chosen in order to study the chemical composition of 100% expandable saponite, 50% expandable corrensite and 10% expandable chlorite-saponite mixed-layer mineral C90–S10 Two sets of microchemical analyses were performed in order to determine the variations of the composition on large and small numbers of particles. X-ray diffraction (XRD) and Mössbauer spectrometry were performed on purified samples.The mathematical decomposition of Si, Al and Mg histograms established from microanalyses of a large number of crystals of saponite, corrensite and C90–S10 evidences bimodal populations. The total Fe content of the three species is unimodal whatever the chemical composition of the surrounding rock and the Fe2+/Fe3+ ratio. The structural formulae established from a large number of microanalyses of a few particles show that there are no parental relationships between saponite, corrensite and C90–S10. The expandable layer of corrensite is characterized by a high charge. It is proposed that the tetrahedral sheets adjacent to the brucitic sheet and the exchangeable interlayer in a 2 : 1 unit are identical in corrensite.


2020 ◽  
Author(s):  
Sujata Murty ◽  
Caroline Ummenhofer ◽  
Markus Scheinert ◽  
Erik Behrens ◽  
Arne Biastoch ◽  
...  

<p>The Indonesian Throughflow (ITF) serves as an important oceanic teleconnection for Indo-Pacific climate, altering heat and buoyancy transport from the Pacific to the Indian Ocean. Equatorial Pacific wind forcing transmitted through the ITF impacts interannual to interdecadal Indian Ocean thermocline depth and heat content, with implications for preconditioning Indian Ocean Dipole events. Yet the modulation of Indian Ocean thermal properties at seasonal timescales is still poorly understood. Here we synthesize coral δ<sup>18</sup>O records, instrumental indices (El Niño Southern Oscillation (ENSO), Asian Monsoon), and simulated ocean variability (sea surface salinity (SSS) and temperature (SST), heat content, mixed layer depth) from state-of-the-art NEMO ocean model hindcasts to explore drivers of seasonal to multi-decadal variability. All coral sites are located within main ITF pathways and are influenced by monsoon-driven, buoyant South China Sea (SCS) surface waters during boreal winter that obstruct surface ITF flow and reduce heat transport to the Indian Ocean. Makassar and Lombok Strait coral δ<sup>18</sup>O co-varies with simulated SSS, subsurface heat content anomalies (50-350m) and mixed layer depth at the coral sites and in the eastern Indian Ocean. At decadal timescales, simulated boreal winter ocean variability at the coral sites additionally indicates a potential intensification of the SCS buoyancy plug from the mid- to late-20<sup>th</sup> century. Notably, the variability in these coral and model responses reveals sensitivity to phase changes in the Interdecadal Pacific Oscillation and the East Asian Winter Monsoon. These results collectively suggest that the paleoproxy records are capturing important features of regional hydrography and Indo-Pacific exchange, including responses to regional monsoon variability. Such proxy-model comparison is critical for understanding the drivers of variability related to changes in ITF oceanic teleconnections over the 19<sup>th</sup> and 20<sup>th</sup> centuries.</p>


Clay Minerals ◽  
1999 ◽  
Vol 34 (2) ◽  
pp. 333-344 ◽  
Author(s):  
B. A. Sakharov ◽  
H. Lindgreen ◽  
A. L. Salyn ◽  
V. A. Drits

AbstractThe finest fractions of Upper Jurassic shales from the North Sea and onshore Denmark contain 80–90% of an illite-smectite-vermiculite (I-S-V) mixed-layer mineral and, in addition a phase which has X-ray diffraction (XRD) peaks at 7.20–7.26 Å and 3.56–3.58 Å in air- dried and glycolated specimens. This phase may be a fine kaolinite with a small thickness of coherent scattering domains (CSDs) or alternatively a mixed-layer mineral which has kaolinite as the dominant component. For one sample from the Norwegian well 9/4-3, these alternatives are investigated using the multi-specimen method by which agreement between the experimental pattern and the pattern calculated for one and the same structure is obtained for each of several specimens saturated with different cations and with/without glycolation. It is demonstrated that the modelled XRD patterns for a kaolinite-illite-vermiculite (K-I-V) structure having 0.94 kaolinite, 0.03 illite and 0.03 vermiculite layers and random alternation fit the experimental patterns.


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