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Lescinskis, Oskars, Ruta Švinka y Visvaldis Švinka. "Common and Different in Latvian Clay Minerals". Key Engineering Materials 762 (febrero de 2018): 268–72. http://dx.doi.org/10.4028/www.scientific.net/kem.762.268.
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Clays are materials consisting of clay minerals and non-clay minerals. Some applications allow to use raw clay others require to separate clay minerals from non-clay minerals. Clay mineral fraction is considered to be a nanofraction. Description and characterization of 3 different Latvian clay nanosized minerals from 3 different geological periods (clay Liepa from Devonian period, clay Vadakste from Triassic period and clay Apriki from Quaternary period) are summarized. The main mineral in these clays is illite, however the presence of kaolinite is observed and its quantity depends on geological period in which clays formed. Nanosized clay mineral particles were obtained using sedimentation method. Comparison of mineralogical composition, BET nitrogen adsorption, zeta potential, DTA/TG analysis and FTIR spectra is given. XRD phase analysis results were very close to each other and shows that mineral of illite is more than that of kaolinite. BET nitrogen adsorption data shows that clay minerals of Apriki has the highest specific surface area (81 m2/g), whereas clay minerals of Vadakste has it the lowest (43 m2/g). Zeta potential values for clay minerals Apriki, Liepa and Vadakste are-40.9 mV, -49.6 mV and-43.0 mV, respectively. DTA analysis and FTIR spectra show similar tendencies for all 3 clay minerals.
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Hurst, A. "Textural and geochemical micro-analysis in the interpretation of clay mineral characteristics: lessons from sandstone hydrocarbon reservoirs". Clay Minerals 34, n.º 1 (marzo de 1999): 137–49. http://dx.doi.org/10.1180/000985599545993.
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AbstractBack-scattered electron images of clay minerals from sandstones are used, together with complementary micro-analytical methods, to identify and quantify mineral microporosity and geochemistry. Clay minerals typically have a range of microporosity from 10 to >90% dependent on texture and paragenesis. Fibrous clays are highly microporous; detrital clays have low microporosity but specific clay minerals have broad ranges of microporosity. The often quoted mineral-chemical association between thorium (Th) and kaolinite cannot be substantiated by micro-analysis. The Th content of clay minerals is associated with micro-inclusions within the kaolinite which form diagenetically or are derived from precursor minerals.
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Murray, H. H. "Applied clay mineralogy today and tomorrow". Clay Minerals 34, n.º 1 (marzo de 1999): 39–49. http://dx.doi.org/10.1180/000985599546055.
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AbstractThe clay minerals kaolin, smectite and palygorskite-sepiolite are among the world's most important and useful industrial minerals. Clay minerals are important in a number of geological applications such as stratigraphic correlations, indicators of environments of deposition and temperature for generation of hydrocarbons. In agriculture, the clay minerals are a major component of soils and determinant of soil properties. The clay minerals are important in construction where they are a major constituent in brick and tile. The physical and chemical properties of the clay minerals determine their utilization in the process industries.What about tomorrow? Processing techniques will be improved and new equipment will be available so that improved clay mineral products will be available. Pillared clays and nanocomposites will become important. Further developments in organoclay technology and surface treatments will provide new usages for these special clays. Tomorrow will see further growth and utilization of the clay minerals.
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KOROLEV, V. А. "THE ECOLOGICAL ROLE OF CLAYS AND CLAY MINERALS". Engineering Geology World 14, n.º 1 (15 de junio de 2019): 60–71. http://dx.doi.org/10.25296/1993-5056-2019-14-1-60-71.
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The article considers the ecological role played by clays and clay minerals in the ecosystem and the biosphere as a whole. The value of clays and clay minerals in the origin of life on Earth and the formation of RNA are analyzed, due to the periodicity of the microstructure of these minerals, their physicochemical activity and sorption capacity with respect to amino acids, nucleotides, proteins and RNA. The processes of interaction of clay minerals with organic matter are considered, including under conditions of hydrothermal conditions, which have specific features that contribute to the origin of life. In addition, the ecological functions of the lithosphere due to clays and clay minerals were analyzed. It is shown that clays and clay minerals perform the most important ecological resource function, being a valuable mineral resource and mineral, participating in providing biota (including humans) with various mineral and energy resources of minerals, in providing biophilic resources, in providing renewable resources (water, oil and gas), in providing resources of the geological space, etc. Also, the clays perform an important ecological geochemical function, which consists in their participation in the geochemistry processes of the lithosphere and the formation of specific geochemical barriers that perform protective ecological functions on the migration routes of various contaminants. The ecological geodynamic function of clays consists in their influence on the development of endogenous and exogenous geological processes affecting the state and functioning of ecosystems. Finally, the participation of clays in ensuring the geophysical ecological function of the lithosphere consists in their influence on the formation of both natural and man-made geophysical fields in ecological-geological systems. Thus, clays and clay minerals have a great influence on ecological and geological systems, they are involved in the formation of all the most important ecological functions of the lithosphere: resource, geochemical, geodynamic and geophysical. Among them, the most significant is the role of clays and clay minerals in ensuring the resource ecological function of the lithosphere.
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Yang, Er-jing, Sha-sha Zeng, Hong-yan Mo, Cheng-lin Yang, Cheng Chen y Yan-fu Wang. "Analysis of the Mineral Compositions of Lateritic Clay in Guangxi and their Influence". Advances in Materials Science and Engineering 2022 (11 de mayo de 2022): 1–9. http://dx.doi.org/10.1155/2022/4068773.
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In order to study the effect of mineral composition on the physical properties of lateritic clays, the mineral compositions of four kinds of lateritic clay from Guangxi province in China were quantitatively analyzed by means of DTA, XRD, SEM, XRF and total chemical element analysis. On this basis, the variation law of macroscopic physical properties of lateritic clay was analyzed from the perspective of mineralogy. The results show that kaolinite and goethite are the main minerals of lateritic clays from Guangxi in China. The mineral compositions of these four samples are quantitatively and accurately analyzed by Bogue’s method. According to the study on mineral compositions of soil samples, the physical properties of lateritic clay are related to its clay minerals and cemented substances. The liquid limit (LL) or plastic limit (PL) increases with the increase of the ability and content of clay minerals to adsorb water. The lateritic clay is dominated by kaolinite minerals with low adsorption capacity, so the observed boundary water content (LL and PL) of high value of lateritic clays can be explained by the contribution of “inert water” in soil pores. The iron-bonded cement minerals (the form of existence is goethite) in lateritic clay have great influence on the liquid and plastic limits, which decrease linearly with the increase of goethite, whereas the goethite has relatively smaller effect on shrinkage characteristics. It is believed that the shrinkage characteristics of lateritic clay may also be affected by other factors.
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Leščinskis, Oskars, Ruta Švinka y Visvaldis Švinka. "Adsorption of Organic Compounds on Refined Latvian Clay". Key Engineering Materials 788 (noviembre de 2018): 83–88. http://dx.doi.org/10.4028/www.scientific.net/kem.788.83.
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Clays are materials consisting of clay minerals and non-clay minerals. Clay mineral fraction is considered to be a nanofraction. Clay minerals can be used for water purification and treatment. Description and characterization of 3 different Latvian clay nanosized minerals from 3 different geological periods (clay Liepa from Devonian period, clay Vadakste from Triassic period and clay Apriki from Quaternary period) as well as their adsorption capacity concerning organic compounds such as methyl orange and rhodamine B are summarized. Nanosized clay mineral particles were obtained using sedimentation method. Particle size distribution, zeta potential and FTIR spectra is given. The adsorption tests of above mentioned organic compounds were carried out in water solutions at 3 different pH values. The adsorption values were determined by means of UV-spectrophotometric technique. Zeta potential values for clay minerals Apriki, Liepa and Vadakste are -40.9 mV, -49.6 mV and -43.0 mV, respectively. FTIR spectra show similar tendencies for all 3 clay minerals. The best adsorption capacity concerning methyl orange and rhodamine B were in solutions with a pH value of 2, whereas at neutral and alkaline pH values adsorption in 24 hours was not observed.
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Pozo, Manuel y José Calvo. "An Overview of Authigenic Magnesian Clays". Minerals 8, n.º 11 (9 de noviembre de 2018): 520. http://dx.doi.org/10.3390/min8110520.
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Clay authigenesis mostly concerns: (a) the formation of clays by direct precipitation from solution, called “neoformation” and (b) development of clays by transformation of precursor minerals. Precipitation from solution implies that a new mineral structure crystallizes, so that a prior mineral structure is not inherited. Transformation of precursor detrital minerals, a process also termed “neoformation by addition”, can be conducted whether throughout precipitation on pre-existing natural surfaces or transformation and reaction on pre-existing surfaces. Both processes have been recognized as effective mechanisms in the formation of Mg-clays, which mostly include 2:1 clay minerals, such as talc-kerolite and Mg-smectites, as well as fibrous clays (sepiolite, palygorskite). Authigenic Mg-clay minerals occur in both modern and ancient marine and non-marine depositional environments, although formation of these clays in hydrothermal continental and seafloor settings must be also outlined. Most favourable conditions for the formation of Mg-clays on earth surface are found in evaporitic depositional environments, especially where parent rocks are enriched in ferromagnesian minerals. In these settings, Mg-clays are important constituent of weathering profiles and soils and can form thick deposits of significant economic interest. Based on this review of authigenic clay deposits, we propose three geochemical pathways, mainly related to continental environments, for the origin of authigenic Mg-clays: formation of Al-bearing Mg-clays (pathway 1), formation of Al-free Mg clays (pathway 2) and formation of sepiolite from other Mg-clay minerals (pathway 3).
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Ushnickaya, H. y A. Mestnikov. "INVESTIGATION OF THE PROPERTIES OINVESTIGATION OF THE PROPERTIES OF CLAY RAW MATERIALS BY METHODS OF PHYSICO-CHEMICAL ANALYSIS". Bulletin of Belgorod State Technological University named after. V. G. Shukhov 9, n.º 4 (20 de febrero de 2024): 16–25. http://dx.doi.org/10.34031/2071-7318-2024-9-4-16-25.
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The article presents the results of the study of the properties of clay raw materials using modern methods of physico-chemical analysis: X-ray fluorescence analysis (XRF), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and thermal analysis. Two types of clay raw materials based on the color of the ceramic shard were considered: light-burning and red-burning clays. The studied clay raw materials contain a small amount of clay minerals and a high content of dusty particles, belong to moderately plastic and medium plastic clays and loams. X-ray spectral analysis allowed to determine the chemical quantitative composition of the main oxides of clay raw materials. Thermal analysis of natural clay raw materials, which have a polymineral composition, reveals exothermic and endothermic effects characteristic of the studied minerals – montmorillonite and kaolinite. According to the mineral composition, the clay raw materials of Central Yakutia are polymineral, with the main clay minerals being montmorillonite and kaolinite, and quartz, calcite, chlorite, minerals from the mica and feldspar groups, and mixed-layer minerals found as impurities. The low quality of the clay raw material suggests that further research should be conducted to improve the technological and physical-mechanical properties of ceramic products made from local clay raw material. In the design of raw material mixtures, local natural and man-made mineral raw materials can be used.
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Shan, Yi, Xing Wang, Jie Cui, Haihong Mo y Yadong Li. "Effects of Clay Mineral Composition on the Dynamic Properties and Fabric of Artificial Marine Clay". Journal of Marine Science and Engineering 9, n.º 11 (3 de noviembre de 2021): 1216. http://dx.doi.org/10.3390/jmse9111216.
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Marine clays are easily affected by different mineral composition in cyclic load-based geological hazards. Therefore, based on analyzing the mineral composition of natural marine clay, it is the key to predict the dynamic properties of natural materials under cyclic loading by using quantitated artificial marine clay. In this study, the marine clay found in the South China Sea deltas was investigated. Based on the results of geological conditions and mineral composition analyses, raw non-clay minerals (such as quartz, albite) and clay minerals (such as Na-montmorillonite and kaolinite) were used to produce artificial marine clay, the dynamic properties of which were studied from the impact of mineral composition. Dynamic triaxial laboratory testing for artificial marine clay comprising various clay minerals was performed under identical test conditions. The artificial marine clay with high montmorillonite content exhibited slower development of strain, more sluggish growth in pore water pressure, more rounded hysteresis curves, greater stiffness, and more prolonged viscous energy growth than the clay with low montmorillonite content. In addition, the flocculated fabric of the artificial marine clay with high montmorillonite content demonstrated sufficient pore space changes, more uniform pore distribution, and larger specific surface area than the dispersed fabric of the clay with low montmorillonite content. The factors arising from the influence of montmorillonite may lead to microstructural and fabric changes, hinder the development of pore water, and increase intergranular contact stiffness as well as delay the cyclic strain amplitude at the breakpoint of viscous energy dissipation. In general, the results presented in this study confirm that clay minerals, especially montmorillonite, have significant influence on the dynamic properties of large strain.
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Raina, A. y Hishmi Hussain. "Sand and clay mineralogy of soils of Garhwal Himalaya, Uttarakhand". Indian Journal of Forestry 32, n.º 4 (1 de diciembre de 2009): 553–57. http://dx.doi.org/10.54207/bsmps1000-2009-s3ny24.
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Fine sand and clay mineralogy of selected horizons of forest soils representing various landforms of Maldeota, Satengal and Dhanaulti areas of Raipur and Jaunpur ranges of Mussoorie forest division of Garhwal Himalaya were investigated. Light minerals constituted more than 80 percent of total fine sand fractions and consisted of quartz, feldspar and mica in order of their abundance. Heavy minerals occurred in minute amounts and constitute 20 percent of the minerals and were dominated by opaque minerals followed by biotite, chlorite, chloritized mica, zircon, garnet, hornblende, tourmaline, rutile etc. Quartz is the dominant mineral in Maldeota and Satengal sites followed by Dhanaulti while feldspar and mica are abundant in Dhanaulti followed by Maldeota and Satengal. Among the heavy minerals opaque minerals, biotite and calcite are present in appreciable quantity in all the three sites viz. Maldeoata, Satengal and Dhanaulti. The other heavy minerals are present in small quantities at all the three sites. The clay fractions from the soils of Maldeota are characterized by illite as the dominant clay mineral associated with kaolinite, chlorite, vermiculite and quartz. The clays from Satengal contained mixture of illite as dominant mineral followed by mica, mixed layer minerals, vermiculite, chlorite and quartz. The soil clays from Dhanaulti indicates the presence of illite, muscovite, kaolinite, mixed layer minerals, chlorite and small traces of vermiculite, calcite and quartz. Differences in mineralogical make up were mostly associated with nature and composition of parent material and degree of weathering. The study, therefore, suggests that soils of the study area contained low to moderate amount of weatherable minerals indicating their podzolic nature.
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Jeong, G. Y. y E. P. Achterberg. "Chemistry and mineralogy of clay minerals in Asian and Saharan dusts and the implications for iron availability". Atmospheric Chemistry and Physics Discussions 14, n.º 11 (17 de junio de 2014): 15735–70. http://dx.doi.org/10.5194/acpd-14-15735-2014.
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Abstract. Mineral dust supplied to remote ocean regions stimulates phytoplankton growth through delivery of micronutrients, notably iron (Fe). Although attention is usually paid to Fe (hydr)oxides as major sources of available Fe, Fe-bearing clay minerals are typically the dominant phase in mineral dust. The mineralogy and chemistry of clay minerals in dust particles, however, are largely unknown. We conducted microscopic identification and chemical analysis of the clay minerals in Asian and Saharan dust particles. Cross-sectional slices of dust particles were prepared by focused ion beam (FIB) techniques and analyzed by transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDXS). TEM images of FIB slices revealed that clay minerals occurred as either nano-thin platelets or relatively thick plates. The nano-thin platelets included illite, smectite, illite–smectite mixed layers and their nanoscale mixtures (illite–smectite series clay minerals, ISCMs) which could not be resolved with an electron microbeam. EDXS chemical analysis of the clay mineral grains revealed that the average Fe content was 5.8% in nano-thin ISCM platelets assuming 14% H2O, while the Fe content of illite and chlorite was 2.8 and 14.8%, respectively. In addition, TEM and EDXS analyses were performed on clay mineral grains dispersed and loaded on microgrids. The average Fe content of clay mineral grains was 6.7 and 5.4% in Asian and Saharan dusts, respectively. A comparative X-ray diffraction analysis of bulk dusts showed that Saharan dust was more enriched in clay minerals than in Asian dust, while Asian dust was more enriched in chlorite. The average Fe / Si, Al / Si and Fe / Al molar ratios of the clay minerals, compared to previously reported chemistries of mineral dusts and leached solutions, indicated that dissolved Fe originated from clay minerals. Clay minerals, in particular nanocrystalline ISCMs and Fe-rich chlorite are important sources of available Fe in remote marine ecosystems. Further detailed analyses of the mineralogy and chemistry of clay minerals in global aerosols are required to determine the inputs of Fe available to surface ocean microbial communities.
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Belghazdis, Mohammed y El-Kaber Hachem. "Clay and Clay Minerals: A Detailed Review". International Journal of Recent Technology and Applied Science 4, n.º 2 (29 de septiembre de 2022): 54–75. http://dx.doi.org/10.36079/lamintang.ijortas-0402.367.
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In this study, we focused on the presentation of clay minerals, their conditions of formation and their different categories. We also reported the importance of purification in removing impurities and the responses induced by heat treatment of these minerals. Techniques used to detect clay minerals are also exposed. On the other hand, the mineralogical, physicochemical and thermal properties have a direct impact on the field of use of these minerals. These properties differ from one mineral to another, depending on the structure and chemical composition. Moreover, the remarkable properties of smectites make these minerals the most preferred for the industry and also in the environmental field. Due to their brilliant firing properties, illites are suitable for the construction industry. Moreover, the purification by acids (acetic acid and HCl) allows the removal of most associated minerals, and thus a secure access to the clays' characteristics and a very strong sensitization even to the small variation. Finally, the ethylene glycol (EG) swelling test only affects the basal distance of smectites, increasing this distance to 17 Å, but heating to 500°C destroys kaolinite, and closes the basal distance of smectites and vermiculites to 10 Å. Illites and chlorites show no response to these two treatments (EG, heating to 500°C).
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Min, Fanfei, Lujun Wang, Jun Chen, Chunfu Liu, Bao Ren, Lianfeng Zhang y Yi Zhu. "Molecular simulation in surface hydration of clay minerals: a review of theory and applications". Minerals and Mineral Materials 1, n.º 1 (2022): 3. http://dx.doi.org/10.20517/mmm.2022.01.
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Clay minerals, which are prevalent gangue minerals, are found in tailings and beneficiation effluent after the extraction of valuable minerals. The surface of clay mineral particles is easy to hydrate, which makes it the main factor restricting tailings separation and wastewater treatment. However, the microscopic mechanism of clay mineral particle surface hydration is not yet systematic. In recent years, with the development of molecular simulation theory and the improvement of computational efficiency, density functional theory (DFT) and molecular dynamics (MD) have gradually become a powerful tool for studying the surface hydration of clay mineral particles, which provides new insight into the interaction between the crystal structures of clay minerals and the interfacial interaction in surface hydration of clay mineral particles at the molecular or atomic levels. This article first reviews the basic theory of DFT and MD, then reviews the research progress on clay mineral surface hydration. From the perspective of molecular simulation, a comprehensive discussion of the clay mineral phase structure, the establishment of the supercell surface model, the clay-water interface interaction and the limitations of molecular simulation was conducted. Water molecules can adsorb with different mineral surfaces in slime water through hydrogen bond, which is the basis of surface hydration mechanism. The hydration layer is composed of three water layers with different densities, with a thickness of about 8-10 Å. Water and ions form hydrate cations, which are adsorbed on the surface of clay minerals, change the structure of water layer on the surface of minerals. This article ends with a brief discussion of conclusions and perspectives.
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Yanik, G., R. Ceylantekin, E. Taşçi y Ü. Özçay. "The Şahin village (Kütahya, Turkey) clay deposit and its possible utilization". Clay Minerals 47, n.º 1 (marzo de 2012): 1–10. http://dx.doi.org/10.1180/claymin.2012.047.1.1.
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AbstractThe Şahin-village clay deposit, situated in the vicinity of Kütahya, western Turkey, has a promising reserve suitable for tile production. In order to evaluate its potential use, 27 clay samples were collected and their mineralogical, chemical, firing and technological properties were evaluated. The reaction of samples with dilute HCl, dispersion in water and their swelling properties were determined. Mineral identification studies were conducted using X-ray powder diffraction (XRD), differential thermal analyses (DTA) and scanning electron microscopy (SEM) techniques. Analysis showed that clay minerals are illite, kaolinite and montmorillonite. Non-clay minerals are quartz, muscovite, microcline and goethite. The clay samples consisted mainly of SiO2 and Al2O3 corresponding to about 81–83% (average) because of the presence of clay minerals and quartz, accompanied by a significant amount of iron oxide. Mineralogical, chemical, thermal analysis and technological tests showed that the clays from Şahin village could be used for stoneware tiles, tile and brick-making.
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Tretjakova, Rasma y Andris Karpovičs. "MINERAL COMPOSITION OF SOME LATGALE LAKE SEDIMENTS". ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (20 de junio de 2019): 304. http://dx.doi.org/10.17770/etr2019vol1.4146.
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Our research is focused on sedimentological conditions and postdepositional changes of recent fine grained lake sediments. We used bulk sediment mineralogical composition and grain size distribution as indicators to identify sediment source areas and possible changes during Holocene. We analysed fine grained (clayey) sediments from three Latgale lakes - Zeili, Pauguļi and Plusons, situated in Latgale upland. Lake sediments cover Late Pleistocene glacial deposits – loam and sandy loam. Bulk mineral composition of 6 sediment samples was determined by X-ray diffraction (XRD). Sediments contained typical minerals found in surrounding glacial sediments: rock-forming minerals as quartz, plagioclase, albite, enstatite, dolomite, calcite, and clay minerals - illite, kaolinite. To identify postdepositional changes in lake sediments of Holocene age clay minerals in clay fraction (<2 mkm) should be analysed. Particularly illite, smectite mixed layered minerals - illite/smectite (I/Sm) and chlorite. Additionally, grain size distribution of studied lake sediments was analysed. Accordingly, our studied sediments are clays, silty clays and clayey silts with bimodal particle distribution, except two samples from Zeiļi and Plusons with unimodal distribution.
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Długosz, Jacek, Barbara Kalisz y Andrzej Łachacz. "Mineral matter composition of drained floodplain soils in north-eastern Poland". Soil Science Annual 69, n.º 3 (1 de septiembre de 2018): 184–93. http://dx.doi.org/10.2478/ssa-2018-0019.
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Abstract Soils in two river valleys (Rozoga and Omulew) in north-eastern Poland were investigated. The valleys are located on a sandy outwash plain formed during the Vistulian (Weichelian) Glaciation. The soils are drained, used as meadows and classified as Fluvic Umbric Gleysol, Fluvic Mollic Gleysol, and Eutric Fluvic Histic Gleysol (IUSS Working Group WRB 2015). The aim of the study was to identify the composition of mineral matter and to determine the types of clay minerals and intermediate stages of clay minerals by means of the X-ray diffraction (XRD). The studied floodplain soils are rich in organic matter and contain considerable mineral alluvial admixtures. The content of clay fraction (< 2.0 μm) is low (0.02–5.61% of total mineral matter). Higher content of clay fraction was noted in soils with elevated content of organic matter, which can be evidence of simultaneous accumulation of both components. In deeper depressions occurring in river valleys (oxbow lakes), a specific deposit termed silty telmatic mud (16–24% TOC, 50–75% silt, 3.1–5.6% clay fraction content) was accumulated. On the other hand, in shallow depressions, a muddy deposit was accumulated (5.7–7.7% TOC, sandy texture). The main identified clay minerals were smectite, vermiculite, illite and kaolinite as well as variety of mixed-layer clays. Alluvial clay admixture in studied soil formations showed mineralogical similarity to typical floodplain mineral soils (Fluvisols). Mineral fraction of studied soils is mostly of allochthonous origin.
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Jeong, G. Y. y E. P. Achterberg. "Chemistry and mineralogy of clay minerals in Asian and Saharan dusts and the implications for iron supply to the oceans". Atmospheric Chemistry and Physics 14, n.º 22 (27 de noviembre de 2014): 12415–28. http://dx.doi.org/10.5194/acp-14-12415-2014.
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Abstract. Mineral dust supplied to remote ocean regions stimulates phytoplankton growth through delivery of micronutrients, notably iron (Fe). Although attention is usually paid to Fe (hydr)oxides as major sources of available Fe, Fe-bearing clay minerals are typically the dominant phase in mineral dust. The mineralogy and chemistry of clay minerals in dust particles, however, are largely unknown. We conducted microscopic identification and chemical analysis of the clay minerals in Asian and Saharan dust particles. Cross-sectional slices of dust particles were prepared by focused ion beam (FIB) techniques and analyzed by transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDXS). TEM images of FIB slices revealed that clay minerals occurred as either nano-thin platelets or relatively thick plates. Chemical compositions and lattice fringes of the nano-thin platelets suggested that they included illite, smectite, illite–smectite mixed layers, and their nanoscale mixtures (illite–smectite series clay minerals, ISCMs) which could not be resolved with an electron microbeam. EDXS chemical analysis of the clay mineral grains revealed that the average Fe content was 5.8% in nano-thin ISCM platelets assuming 14% H2O, while the Fe content of illite and chlorite was 2.8 and 14.8%, respectively. In addition, TEM and EDXS analyses were performed on clay mineral grains dispersed and loaded on micro-grids. The average Fe content of clay mineral grains was 6.7 and 5.4% in Asian and Saharan dusts, respectively. A comparative X-ray diffraction analysis of bulk dusts showed that Saharan dust was more enriched in clay minerals than Asian dust, while Asian dust was more enriched in chlorite. Clay minerals, in particular nanocrystalline ISCMs and Fe-rich chlorite, are probably important sources of Fe to remote marine ecosystems. Further detailed analyses of the mineralogy and chemistry of clay minerals in global mineral dusts are required to evaluate the inputs of Fe to surface ocean microbial communities.
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Cuadros, Javier. "Clay minerals interaction with microorganisms: a review". Clay Minerals 52, n.º 2 (junio de 2017): 235–61. http://dx.doi.org/10.1180/claymin.2017.052.2.05.
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AbstractInterest in mineral–microbe interaction has grown enormously over recent decades, providing information in a puzzle-like manner which points towards an ever increasingly intimate relationship between the two; a relationship that can be truly termed co-evolution. Clay minerals play a very central role in this co-evolving system. Some 20 years ago, clay scientists looked at clay mineral–microbe studies as a peripheral interest only. Now, can clay scientists think that they understand the formation of clay minerals throughout geological history if they do not include life in their models? The answer is probably no, but we do not yet know the relative weight of biological and inorganic factors involved in driving clay-mineral formation and transformation. Similarly, microbiologists are missing out important information if they do not investigate the influence and modifications that minerals, particularly clay minerals, have on microbial activity and evolution. This review attempts to describe the several points relating clay minerals and microorganisms that have been discovered so far. The information obtained is still very incomplete and many opportunities exist for clay scientists to help to write the real history of the biosphere.
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Yakobi-Hancock, J. D., L. A. Ladino y J. P. D. Abbatt. "Feldspar minerals as efficient deposition ice nuclei". Atmospheric Chemistry and Physics Discussions 13, n.º 6 (28 de junio de 2013): 17299–326. http://dx.doi.org/10.5194/acpd-13-17299-2013.
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Abstract. Mineral dusts are well known to be efficient ice nuclei, where the source of this efficiency has typically been attributed to the presence of clay minerals such as illite and kaolinite. However, the ice nucleating abilities of the more minor mineralogical components have not been as extensively examined. As a result, the deposition ice nucleation abilities of 24 atmospherically-relevant mineral samples have been studied, using a continuous flow diffusion chamber at −40.0 ± 0.3 °C. The same particle size (200 nm) and particle preparation procedure were used throughout. The ice nucleation behaviour of the pure minerals is compared to that of complex mixtures, such as Arizona Test Dust (ATD) and Mojave Desert Dust (MDD), and to lead iodide, which has been previously proposed for cloud seeding. Lead iodide was the most efficient ice nucleus (IN), requiring a critical relative humidity with respect to ice (RHi) of 122.0 ± 2.0% to activate 0.1% of the particles. MDD (RHi 126.3 ± 3.4%) and ATD (RHi 129.5 ± 5.1%) have lower but comparable activity. From a set of clay minerals (kaolinite, illite, montmorillonite), non-clay minerals (e.g. hematite, magnetite, calcite, cerussite, quartz), and feldspar minerals (orthoclase, plagioclase) present in the atmospheric dusts it was found that the feldspar minerals (particularly orthoclase), and not the clays, were the most efficient ice nuclei. Orthoclase and plagioclase were found to have critical RHi values of 127.1 ± 6.3% and 136.2 ± 1.3%, respectively. The presence of feldspars (specifically orthoclase) may play a significant role in the IN behaviour of mineral dusts despite their lower percentage in composition relative to clay minerals.
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Smith, D. K., G. G. Johnson y R. Jenkins. "A Full-Trace Database for the Analysis of Clay Minerals". Advances in X-ray Analysis 38 (1994): 117–25. http://dx.doi.org/10.1154/s0376030800017717.
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Abstract A file of digitized diffraction traces for clay minerals has been developed as a test for the usefulness of such traces in the analysis of clays and clay deposits. The kaolin, smectite, mica clay and chlorite groups are represented by patterns of the most common mineral species in the small crystallite size which is typical of their natural occurrences. Patterns are included for the oriented sample and for glycolated and heated samples when appropriate. This database may form a nucleus for an extensive collection of clay mineral traces in the same manner as the early Powder Diffraction File did for the modern PDE.
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Kim, Hyesu, Jaehyung Yu, Lei Wang, Yongsik Jeong y Jieun Kim. "Variations in Spectral Signals of Heavy Metal Contamination in Mine Soils Controlled by Mineral Assemblages". Remote Sensing 12, n.º 20 (9 de octubre de 2020): 3273. http://dx.doi.org/10.3390/rs12203273.
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This paper illustrates a spectroscopic analysis of heavy metal concentration in mine soils with the consideration of mineral assemblages originated by weathering and mineralization processes. The mine soils were classified into two groups based on the mineral composition: silicate clay mineral group (Group A) and silicate–carbonate–skarn–clay mineral group (Group B). Both soil groups are contaminated with Cu, Zn, As, and Pb, while the contamination level was higher for Group A. The two groups exhibit different geochemical behaviors with different heavy metal contamination. The spectral variation associated with heavy metal was highly correlated with absorption features of clay and iron oxide minerals for Group A, and the absorption features of skarn minerals, iron oxides, and clay minerals for Group B. It indicates that the geochemical adsorption of heavy metal elements mainly occurs with clay minerals and iron oxides from weathering, and of skarn minerals, iron oxides, and clay minerals from mineralization. Therefore, soils from different secondary mineral production processes should be analyzed with different spectral models. We constructed spectral models for predicting Cu, Zn, As, and Pb in soil group A and Zn and Pb in soil group B using corresponding absorptions. Both models were statistically significant with sufficient accuracy.
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Karpiński, B. y M. Szkodo. "Clay Minerals – Mineralogy and Phenomenon of Clay Swelling in Oil & Gas Industry". Advances in Materials Science 15, n.º 1 (1 de marzo de 2015): 37–55. http://dx.doi.org/10.1515/adms-2015-0006.
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Abstract Among the minerals found in the earth's crust, clay minerals are of the widest interest. Due to the specific properties such as plasticity, absorbing and catalytic properties clay minerals are used in many industries (oil & gas, chemistry, pharmacy, refractory technology, ceramics etc.). In drilling, a phenomenon of swelling clays is frequently observed. It has an important impact on the cementing quality. During the last few decades clays have been the subject of research on a scale unprecedented in the history of mineralogy. This paper presents review literature on mineralogy of clay minerals and phenomenon of swelling in oil and gas industry. Unique ion exchange properties and clay swelling mechanisms are also considered.
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Mamadalieva, Sadokat, Gulomkodir Mirzakulov, Erkin Kakharov, Usmonali Sodikov, Umida Kurbanova y Sodir Makhmudov. "Enrichment of mineral raw materials: Selection of local clay minerals for the purpose of obtaining adsorbents for purification of petroleum products". E3S Web of Conferences 525 (2024): 01009. http://dx.doi.org/10.1051/e3sconf/202452501009.
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Geotechnologies and subsoil use play a key role in the rational development of the mineral resource complex, requiring innovative approaches to the enrichment of mineral raw materials. This article discusses a promising direction in the beneficiation of mineral raw materials, focused on obtaining adsorbents from local clay minerals for the effective purification of petroleum products and environmental protection. The article presents a study on the potential of local clay minerals to create effective adsorbents using a mechanochemical activator. The study includes a review of the chemical and mineralogical composition of clays collected in the region, as well as their particle size distribution and differential thermal analysis.
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Pereira, I. D. S., V. N. F. Lisboa, I. A. Silva, J. M. R. Figueirêdo, G. A. Neves y R. R. Menezes. "Bentonite Clays from Sossego, Paraiba, Brazil: Physical and Mineralogical Characterization". Materials Science Forum 798-799 (junio de 2014): 50–54. http://dx.doi.org/10.4028/www.scientific.net/msf.798-799.50.
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In the northeastern region Brazil, especially in the State of Paraíba, there is a large incidence of non-metallic minerals, among which we may highlight the bentonite clay, ball clay, smectitic clay, kaolin... limestone and mica. In past years, there has been an intense research for discovering new deposits in the State of Paraíba, thus creating expectations for widening the mineral raw production in that region. So, this work is intended to make the physical, mineralogical and technological characterization of smectitic clays from the town of Sossego, PB, Brazil. The characterization was made by means of the following techniques: granulometric analysis by laser diffraction (GA), themogravimetric and differential thermal analysis (TG and DTA), chemical analysis (EDX) and X-ray diffraction (XRD). The results evidence that the studied clays present the following mineral phases: smectitic, kaolinite and accessory minerals such as quartz, carbonates feldspars and mica.
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Mohammed, Iqbal j. y Sa'ad Z. Al-Mashaikie. "ORIGIN AND DISTRIBUTION OF CLAY MINERALS IN THE MUDSTONES OF THE KOLOSH FORMATION INRAWANDOZ AREA, NORTHEASTERN IRAQ". Iraqi Geological Journal 51, n.º 2 (31 de diciembre de 2018): 75–90. http://dx.doi.org/10.46717/igj.51.2.5ms-2018-12-27.
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The mudstone/ shale units constituted 60% of the Kolosh Formation of 170 m thickness, which were studied and the clay minerals were identified to conclude the origin and paleoclimate. The studied area is located near the suture of Zagros Thrust Ophiolite Zone in NE Iraq. Kolosh mudstones contain chlorite, vermiculite, illite, nontronite, serpentine with varieties of mixed-layer clays. These clay minerals are of detrital and diagenetic origin, which are controlled mainly by the source rocks, paleoclimatic conditions and the burial diagenesis. Some of chlorite, chlorite/ vermiculite mixed layer, nontronite and smectite refer to hydrothermal origin comes from submarine basaltic flows and the high-temperature pore waters.The distribution of the clay minerals in the stratigraphic section of the Kolosh Formation controlled by episodic thrusting, episodic volcanic eruptions and interbedded sedimentary rock units. These are controlled by the changes in the paleoclimatic conditions, chemical weathering and the diagenetic processes.The clay mineral assemblages refer to be derived mainly from Fe-Mg rich minerals with minor Si-Al rich silicate minerals, which are very common in the ophiolites and associated basic volcanic rocks. These rocks composed the major lithological units in the Zagros Thrust Belt of NE Iraq.
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McBride, M. B. "Chemistry of Clays and Clay Minerals". Clays and Clay Minerals 36, n.º 5 (1988): 480. http://dx.doi.org/10.1346/ccmn.1988.0360515.
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OLIS, ALEXANDER C. "Chemistry of Clays and Clay Minerals". Soil Science 147, n.º 4 (abril de 1989): 309. http://dx.doi.org/10.1097/00010694-198904000-00012.
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Low, Philip F. "Chemistry of clays and clay minerals". Journal of Colloid and Interface Science 125, n.º 1 (septiembre de 1988): 363–64. http://dx.doi.org/10.1016/0021-9797(88)90091-4.
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Yapaskurt, O. V. y V. I. Koporulin. "Conference on clays and clay minerals". Lithology and Mineral Resources 40, n.º 2 (marzo de 2005): 193–94. http://dx.doi.org/10.1007/s10987-005-0021-0.
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Drits, V. A. y B. B. Zvyagina. "International conference “Clays and Clay Minerals”". Lithology and Mineral Resources 42, n.º 5 (septiembre de 2007): 501–2. http://dx.doi.org/10.1134/s0024490207050094.
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Hunter, Keith A. "Chemistry of clays and clay minerals". Geochimica et Cosmochimica Acta 52, n.º 5 (mayo de 1988): 1319. http://dx.doi.org/10.1016/0016-7037(88)90287-6.
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Garvie, L. A. J. "Interstrat—An Expert System to Help Identify Interstratified Clay Minerals from Powder XRD Data: II. Testing the Program". Clay Minerals 29, n.º 1 (marzo de 1994): 21–32. http://dx.doi.org/10.1180/claymin.1994.029.1.03.
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AbstractINTERSTRAT is designed to help clay mineralogists identify clay minerals from powder X-ray diffraction data and is especially useful as an aid in the interpretation of interstratified clay minerals. This paper illustrates the use of the INTERSTRAT program in the identification of a set of interstratified clay minerals. One of the examples has been matched against the PDF and the answers compared with those obtained by INTERSTRAT. The most useful features of the program are the knowledge bases of diffraction parameters for the interstratified clay minerals, the ability of the program to compare the clays identified in more than one state and the hierarchical clay text file.
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Siyao, Huang, Xu Mingbiao, Xu Peng, Zhang Yu y Wang Xinying. "Composite Hydration Process of Clay Minerals Simulating Mineral Clay Components and Influence Mechanism of Cations". Energies 15, n.º 20 (13 de octubre de 2022): 7550. http://dx.doi.org/10.3390/en15207550.
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Clay minerals are an important part of the mud shale reservoir, and their type of content has a great impact on the hydration of the formation. The hydration of clay minerals causes a decrease in drilling fluid performance, an increase in pore pressure, and a decrease in rock strength, leading to wellbore wall collapse. Therefore, it is important to study the influence of clay mineral hydration on well-wall stability. In this paper, we analyze the hydration process of clay minerals qualitatively and quantitatively by simulating the mineral clay fraction and the effect of the change in cations on their hydration and clarify the difference in the hydration of different clay minerals. The results show the following: (1) montmorillonite has the most obvious hydration and swelling effect, while the hydration of illite is mainly based on hydration and dispersion, which easily produce exfoliations and fall off in the stratum; kaolinite has poor hydration performance, while chlorite shows certain hydration but low hydration degree. (2) Cations have a certain inhibitory effect on the hydration of clay minerals, and the degree of hydration inhibition is different for different types. (3) Different clay minerals also differ in the form of state after water exposure, as montmorillonite shows swelling, while illite has no swelling, but its dispersion is stronger.
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Vasilopanagos, Christos, Cédric Carteret, Stephen Hillier, Anke Neumann, Harry J. L. Brooksbank y Hugh Christopher Greenwell. "Effect of Structural Fe Reduction on Water Sorption by Swelling and Non-Swelling Clay Minerals". Minerals 12, n.º 4 (7 de abril de 2022): 453. http://dx.doi.org/10.3390/min12040453.
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Ferruginous clay minerals in saturated soils and within hydrocarbon deposits often exist in a reduced state. Upon introduction of dissolved oxygen, or other oxidants, the clay minerals oxidise and changes in mineral surface charge and sorption capacity occur, resulting in changes in hydration as well as flux of intercalated species. Here we examine the sorption of water to the Fe-containing clay minerals nontronite NAu-2 (23 wt% Fe) and illite IMt-2 (7 wt% Fe) as a function of Fe oxidation state and exchangeable cations by means of water vapour volumetry and N2 surface area analysis. The clay minerals were chemically reduced using sodium dithionite. Sorption isotherms of water vapour and nitrogen, controlled relative humidity diffractograms, and chemical analyses were recorded. The results show that, after reduction using sodium dithionite, increased amounts of water vapour and nitrogen were adsorbed to the high Fe content nontronite, despite decreased interlayer separation. Little change was observed for the non-swelling and low Fe content illite. Sodium from the reducing agent was found to exchange with calcium present in the starting clay minerals, and sodium balanced the additional mineral charge generated during reduction. The findings presented in this study deliver improved understanding of sorption at the surface of the reduced clay minerals, which aid constrain the role of clay mineral interfaces in subsurface environments.
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Wilson, M. J. y L. Wilson. "Clay mineralogy and shale instability: an alternative conceptual analysis". Clay Minerals 49, n.º 2 (abril de 2014): 127–45. http://dx.doi.org/10.1180/claymin.2014.049.2.01.
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AbstractThe instability of shales in drilled formations leads to serious operational problems with major economic consequences for petroleum exploration and production. It is generally agreed that the nature of the clay minerals in shale formations is a primary causative factor leading to their instability, although the exact mechanism involved is more debateable. Currently, the principal cause of shale instability is considered to be volume expansion following the osmotic swelling of Nasmectite. However, illitic and kaolinitic shales may also be unstable, so that interlayer expansion cannot therefore be considered as a universal causative mechanism of shale instability. This review considers alternative scenarios of shale instability where the major clay minerals are smectite, illite, mixed-layer illite-smectite (I/S) and kaolinite respectively. The influence of interacting factors that relate to shale clay mineralogy such as texture, structure and fabric are discussed, as are the pore size distribution and the nature of water in clays and shales and how these change with increasing depth of burial. It is found from the literature that the thickness of the diffuse double layer (DDL) of the aqueous solutions associated with the charged external surfaces of clay minerals is probably of the same order or even thicker than the sizes of a significant proportion of the pores found in shales. In these circumstances, overlap of the DDLs associated with exposed outer surfaces of clay minerals on opposing sides of micropores (<2 nm in diameter) and mesopores (2–50 nm in diameter) in a lithostatically compressed shale would bring about electrostatic repulsion and lead to increased pore/ hydration pressure in smectitic, illitic and even kaolinitic shales. This pressure would be inhibited by the use of more concentrated K-based fluids which effectively shrink the thickness of the DDL towards the clay mineral surfaces in the pore walls. The use of soluble polymers would also encapsulate these clay mineral surfaces and so inhibit their hydration. In this scenario, the locus of action with respect to shale instability and its inhibition is moved from the interlamellar space of the smectitic clays to the charged external surfaces of the various clay minerals bounding the walls of the shale pores.
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Khomo, Lesego, Susan Trumbore, Carleton R. Bern y Oliver A. Chadwick. "Timescales of carbon turnover in soils with mixed crystalline mineralogies". SOIL 3, n.º 1 (5 de enero de 2017): 17–30. http://dx.doi.org/10.5194/soil-3-17-2017.
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Abstract. Organic matter–mineral associations stabilize much of the carbon (C) stored globally in soils. Metastable short-range-order (SRO) minerals such as allophane and ferrihydrite provide one mechanism for long-term stabilization of organic matter in young soil. However, in soils with few SRO minerals and a predominance of crystalline aluminosilicate or Fe (and Al) oxyhydroxide, C turnover should be governed by chemisorption with those minerals. Here, we correlate mineral composition from soils containing small amounts of SRO minerals with mean turnover time (TT) of C estimated from radiocarbon (14C) in bulk soil, free light fraction and mineral-associated organic matter. We varied the mineral amount and composition by sampling ancient soils formed on different lithologies in arid to subhumid climates in Kruger National Park (KNP), South Africa. Mineral contents in bulk soils were assessed using chemical extractions to quantify Fe oxyhydroxides and SRO minerals. Because of our interest in the role of silicate clay mineralogy, particularly smectite (2 : 1) and kaolinite (1 : 1), we separately quantified the mineralogy of the clay-sized fraction using X-ray diffraction (XRD) and measured 14C on the same fraction. Density separation demonstrated that mineral associated C accounted for 40–70 % of bulk soil organic C in A and B1 horizons for granite, nephelinite and arid-zone gabbro soils, and > 80 % in other soils. Organic matter strongly associated with the isolated clay-sized fraction represented only 9–47 % of the bulk soil C. The mean TT of C strongly associated with the clay-sized fraction increased with the amount of smectite (2 : 1 clays); in samples with > 40 % smectite it averaged 1020 ± 460 years. The C not strongly associated with clay-sized minerals, including a combination of low-density C, the C associated with minerals of sizes between 2 µm and 2 cm (including Fe oxyhydroxides as coatings), and C removed from clay-sized material by 2 % hydrogen peroxide had TTs averaging 190 ± 190 years in surface horizons. Summed over the bulk soil profile, we found that smectite content correlated with the mean TT of bulk soil C across varied lithologies. The SRO mineral content in KNP soils was generally very low, except for the soils developed on gabbros under more humid climate that also had very high Fe and C contents with a surprisingly short, mean C TTs. In younger landscapes, SRO minerals are metastable and sequester C for long timescales. We hypothesize that in the KNP, SRO minerals represent a transient stage of mineral evolution and therefore lock up C for a shorter time. Overall, we found crystalline Fe-oxyhydroxides (determined as the difference between Fe in dithionate citrate and oxalate extractions) to be the strongest predictor for soil C content, while the mean TT of soil C was best predicted from the amount of smectite, which was also related to more easily measured bulk properties such as cation exchange capacity or pH. Combined with previous research on C turnover times in 2 : 1 vs. 1 : 1 clays, our results hold promise for predicting C inventory and persistence based on intrinsic timescales of specific carbon–mineral interactions.
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Galan, E. "Properties and applications of palygorskite-sepiolite clays". Clay Minerals 31, n.º 4 (diciembre de 1996): 443–53. http://dx.doi.org/10.1180/claymin.1996.031.4.01.
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AbstractThe palygorskite-sepiolite group of clay minerals has a wide range of industrial applications derived mainly from its sorptive, rheological and catalytic properties which are based on the fabric, surface area, porosity, crystal morphology, structure and composition of these minerals. For assessing potential industrial uses, the mineralogical and chemical composition of the clay and its basic physical and physico-chemical parameters must be determined. Then some particular properties of commercial interest can be modified and improved by appropriate thermal, mechanical and acid treatments, surface active agents, organo-mineral derivatives formation, etc. In this paper, a revision of the principal characteristics of commercial palygorskite-sepiolite clays is presented, and potential uses are suggested according to these data. New products and applications are being investigated and those concerning environmental protection in particular, are noted. Finally, possible health effects of these elongate clay minerals are discussed.
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Nedbailo, O. M. y O. G. Chernyshyn. "Technological properties of clay raw materials". Кераміка: наука і життя, n.º 4(49) (23 de enero de 2021): 7–12. http://dx.doi.org/10.26909/csl.4.2020.1.
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The article summarizes and analyzes the technological characteristics of various clay raw materials. Recommendations on the feasibility of their use in various types of ceramic production are given. Their main characteristics are given, such as chemical composition, mineralogical and physical properties, which vary within extremely wide limits. They are most characterized by a layered structure. All clay minerals are considered as secondary geological formations that arose in deposits in which water was present as a product of changes in aluminosilicate rocks. Most clay minerals are the product of weathering and deposition, but they can also be formed in hydrothermal conditions.
In addition to basic clay minerals, clays also contain various amounts of other minerals that often affect their behavior when used. The most common such minerals are quartz, feldspar and minerals containing iron, lime, alkalis and soluble salts. The organic component is also found in many clay deposits. Different classifications of clays are based on their geology, mineralogy, composition, properties and uses, but none of them covers all possible diversity.
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Yakobi-Hancock, J. D., L. A. Ladino y J. P. D. Abbatt. "Feldspar minerals as efficient deposition ice nuclei". Atmospheric Chemistry and Physics 13, n.º 22 (18 de noviembre de 2013): 11175–85. http://dx.doi.org/10.5194/acp-13-11175-2013.
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Abstract. Mineral dusts are well known to be efficient ice nuclei, where the source of this efficiency has typically been attributed to the presence of clay minerals such as illite and kaolinite. However, the ice nucleating abilities of the more minor mineralogical components have not been as extensively examined. As a result, the deposition ice nucleation abilities of 24 atmospherically relevant mineral samples have been studied, using a continuous flow diffusion chamber at −40.0 ± 0.3 °C and particles size-selected at 200 nm. By focussing on using the same experimental procedure for all experiments, a relative ranking of the ice nucleating abilities of the samples was achieved. In addition, the ice nucleation behaviour of the pure minerals is compared to that of complex mixtures, such as Arizona Test Dust (ATD) and Mojave Desert Dust (MDD), and to lead iodide, which has been previously proposed for cloud seeding. Lead iodide was the most efficient ice nucleus (IN), requiring a critical relative humidity with respect to ice (RHi) of 122.0 ± 2.0% to activate 0.1% of the particles. MDD (RHi) 126.3 ± 3.4%) and ATD (RHi 129.5 ± 5.1%) have lower but comparable activity. From a set of clay minerals (kaolinite, illite, montmorillonite), non-clay minerals (e.g. hematite, magnetite, calcite, cerussite, quartz), and feldspar minerals (orthoclase, plagioclase) present in the atmospheric dusts, it was found that the feldspar minerals (particularly orthoclase) and some clays (particularly kaolinite) were the most efficient ice nuclei. Orthoclase and plagioclase were found to have critical RHi values of 127.1 ± 6.3% and 136.2 ± 1.3%, respectively. The presence of feldspars (specifically orthoclase) may play a significant role in the IN behaviour of mineral dusts despite their lower percentage in composition relative to clay minerals.
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Blanchart, P., J. M. Gaillard y F. Weber. "The drying of clay minerals and mixed clay minerals". Journal of Materials Science 30, n.º 9 (mayo de 1995): 2319–24. http://dx.doi.org/10.1007/bf01184580.
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H. Esaa, F. y J. K. Kassim. "IDENTIFICATION AND DISTRIBUTION OF MINERALS IN SOILS FROM AL-AHRAR AREA, WAIST PROVINCE, IRAQ". Journal of Life Science and Applied Research 2, n.º 1 (30 de junio de 2021): 16–23. http://dx.doi.org/10.59807/jlsar.v2i1.26.
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The clay mineralogy of soils and of the main calcareous sedimentary soils of middle of Iraq were investigated to determine the presence of different clay minerals and their distribution pattern in soils. Six pedons were chosen and total of 24 soil horizons were collected. The results revealed that the soil minerals were primary and others were secondary minerals. Generally, the results of the semi-quantitative distribution of the clay minerals in clay fractions showed the dominance of the montmorillonite minerals and illite alternate with chlorite in being main and kaolinite are major, while, the presence of palygorskite mineral were trace except P5 may be miner (saline soils). The origin of the montmorillonite minerals in these soil may be inherited in origin from the mica. Soil chlorite was found in some soils due to chloritization of expanding clay minerals. The mineralogical distribution in bulk soils were dominated by calcite, and quartz, while other minerals were identified feldspar, hematite and pyroxene in addition to the clay minerals in all the soil samples.
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Suttikul, Supaluk, Kanyarat Ano y Kedsarin Pimraksa. "Effect of Calcium Hydroxide Content on Pozzolanic Reaction of Calcined Clays: Their Mechanical Properties and Microstructures". Materials Science Forum 1034 (15 de junio de 2021): 161–68. http://dx.doi.org/10.4028/www.scientific.net/msf.1034.161.
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The research aimed to investigate the effect of calcium hydroxide content on pozzolanic reaction of calcined clays. Pozzolanic reaction of calcined clay was determined in terms of its mechanical properties, phase development and microstructures. Three clay minerals (two kaolinitic clays and kaolinite-montmorillonite clay) were chosen to produce pozzolanic materials via calcination at temperature of 700 °C to allow dehydroxylation of clay minerals. Ratios of calcium hydroxide to calcined clays were varied from 0.1 to 0.5. Mixing water contents or liquid to solid ratios (0.62, 0.75 and 0.80) and curing times (7 and 28 days) were also studied. It was found that calcium aluminosilicate hydrate (stratlingite) could be formed after pozzolanic reactions of all clay minerals. The development of stratlingite agreed with the strength development showing the highest compressive strength at 26 MPa (28 days) when kaolinite-montmorillonite clay was used as pozzolanic material and the ratio of calcium hydroxide to calcined clay was 0.5.
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ROSS, G. J., C. WANG y R. G. HILL. "MINERALOGICAL VARIABILITY OF THE CLAY IN A MAP DELINEATION OF BRANDON SOIL". Canadian Journal of Soil Science 67, n.º 1 (1 de febrero de 1987): 83–93. http://dx.doi.org/10.4141/cjss87-008.
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The mineralogical variability of the clays from the Ap and BCg horizons of 20 pedons in a delineation of Brandon soil near Ottawa was measured. The soil has level topography, is dominantly poorly drained, and has developed from marine clay during the past 8000 yr. Smectite, vermiculite and mica were the dominant clay minerals, whereas quartz, feldspars and amphiboles were generally present in smaller amounts. The coefficients of variation (CV) among pedons were generally less than 20% indicating that the lateral distribution of minerals in the clay was relatively uniform. This was supported by the low variability (CV of 10% or less) of the chemical properties of the clay, such as cation exchange capacities and K contents, which are generally related to clay mineralogy. There were more significant differences in clay mineralogy between Ap and BCg horizons. Differences appear to have resulted from pedogenic weathering. The clay from the Ap horizon contained a higher proportion of smectite and lower proportions of mica, albite and amphiboles. Presumably, some mica had expanded to form smectite and some primary mineral grains had weathered. Decreased total amounts of Na, K and Ca in the Ap clay also reflected this weathering. The lateral uniformity of the clay mineralogy was accounted for by the relatively uniform soil forming factors and processes in this map unit. The confidence limits for variations from means of mineral contents in replicated clays as well as other results indicate that the determination of spatial variability of clay mineralogy is limited by the precision of analytical methods for mineral quantification. Key words: Mineralogical variability, map delineation, Brandon soil
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D.O., IKORO, OKEKE O.C., ABUBARKAR M.T., OGBONNA T. y EZEBUNANWA A. "THE ROLE OF CLAY MINERALS IN HYDROCARBON GENERATION, MIGRATION AND ACCUMULATION". International Journal of Scientific & Engineering Research 13, n.º 09 (25 de septiembre de 2022): 1–24. http://dx.doi.org/10.14299/ijser.2022.09.01.
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This study focuses on the understanding of the role of clay minerals in hydrocarbon generation, migration and accumulation. Clay minerals are involved in the formation of kerogen, catalytic cracking of kerogen into petroleum, migration of crude oil, and the continued change to hydrocarbon composition in petroleum reservoirs. In kerogen formation, clay minerals act as catalysts and sorbents to immobilize organic matter through ligand exchange, hydrophobic interactions and cation bridges by the mechanisms of Maillard reactions, polyphenol theory, selective preservation and adsorptive protection. Clay minerals also serve as catalysts in acid-catalyzed cracking of kerogen into petroleum hydrocarbon through Lewis and Bronsted acid sites on the clay surfaces. The amount and type of clay mineral affect the composition of the petroleum. Bronsted acidity of clay minerals is affected by the presence and state of interlayer water, and displacement of this water is a probable driver in crude oil migration from source rocks. During crude oil migration and accumulation in reservoirs, the composition of petroleum is continually modified by interaction with clay minerals. Clay minerals remain the most difficult of all earth materials to study and characterize. Their sheet structure results in features that can only be resolved at the sub-micron scale. They are also subtly variable in chemical composition (Fe, Mg, K, Al, et cetera) and can be confused with each other and other silicates. The recent innovative analytical tools and modern analysis techniques, example., micro- and nano-X-ray Computed Tomography (XCT), QEMSCAN (Automated Mineralogy and Petrography), FIB/SEM (Focused Ion Beam/Scanning Electron Microscope), EDS (Energy-dispersive X-ray spectroscopy), etc., have the capability of quantitative and qualitative characterizing nano-pore features and mineralogy of fine grained shale rocks, which create new era of studying clay minerals for facilitating unconventional (shale) reservoir exploration. Even though there have been reports about the application of clay minerals in the oil and gas exploration, surprisingly little work has been documented. Keyword: clay mineral, organic matter, generation, vitrinite, kerogen, montmorillonite.
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Zhang, Jun Rui, Meng Dan Xu, Georgios E. Christidis y Chun Hui Zhou. "Clay minerals in drilling fluids: functions and challenges". Clay Minerals 55, n.º 1 (marzo de 2020): 1–11. http://dx.doi.org/10.1180/clm.2020.10.
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AbstractThe addition of clay minerals in drilling fluids modifies the dispersion's viscosity. In this article, scientific advances related to the use of clays and clay minerals (bentonite, palygorskite, sepiolite and mixtures of clay minerals) in drilling fluids are summarized and discussed based on their specific structure, rheological properties, applications, prevailing challenges and future directions. The rheological properties of drilling fluids are affected by the temperature, type of electrolytes, pH and concentration of clay minerals. Bentonites are smectite-rich clays often used in drilling fluids, and their composition varies from deposit to deposit. Such variations significantly affect the behaviour of bentonite-based drilling fluids. Palygorskite is suitable for use in oil-based drilling fluids, but the gelation and gel structures of palygorskite-added drilling fluids have not received much attention. Sepiolite is often used in water-based drilling fluids as a rheological additive. Dispersions containing mixtures of clays including bentonite, kaolin, palygorskite and sepiolite are used in drilling fluids requiring specific features such as high-density drilling fluids or those used in impermeable slurry walls. In these cases, the surface chemistry–microstructure–property relationships of mixed-clay dispersions need to be understood fully. The prevailing challenges and future directions in drilling fluids research include safety, ‘green’ processes and high-temperature and high-pressure-resistant clay minerals.
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Mohammed, Isah, Dhafer Al Shehri, Mohamed Mahmoud, Muhammad Shahzad Kamal, Olalekan Alade, Muhammad Arif y Shirish Patil. "Effect of Native Reservoir State and Oilfield Operations on Clay Mineral Surface Chemistry". Molecules 27, n.º 5 (7 de marzo de 2022): 1739. http://dx.doi.org/10.3390/molecules27051739.
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An understanding of clay mineral surface chemistry is becoming critical as deeper levels of control of reservoir rock wettability via fluid–solid interactions are sought. Reservoir rock is composed of many minerals that contact the crude oil and control the wetting state of the rock. Clay minerals are one of the minerals present in reservoir rock, with a high surface area and cation exchange capacity. This is a first-of-its-kind study that presents zeta potential measurements and insights into the surface charge development process of clay minerals (chlorite, illite, kaolinite, and montmorillonite) in a native reservoir environment. Presented in this study as well is the effect of fluid salinity, composition, and oilfield operations on clay mineral surface charge development. Experimental results show that the surface charge of clay minerals is controlled by electrostatic and electrophilic interactions as well as the electrical double layer. Results from this study showed that clay minerals are negatively charged in formation brines as well as in deionized water, except in the case of chlorite, which is positively charged in formation water. In addition, a negative surface charge results from oilfield operations, except for operations at a high alkaline pH range of 10–13. Furthermore, a reduction in the concentrations of Na, Mg, Ca, and bicarbonate ions does not reverse the surface charge of the clay minerals; however, an increase in sulfate ion concentration does. Established in this study as well, is a good correlation between the zeta potential value of the clay minerals and contact angle, as an increase in fluid salinity results in a reduction of the negative charge magnitude and an increase in contact angle from 63 to 102 degree in the case of chlorite. Lastly, findings from this study provide vital information that would enhance the understanding of the role of clay minerals in the improvement of oil recovery.
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Taylor, R. K. y T. J. Smith. "The engineering geology of clay minerals: swelling, shrinking and mudrock breakdown". Clay Minerals 21, n.º 3 (septiembre de 1986): 235–60. http://dx.doi.org/10.1180/claymin.1986.021.3.01.
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AbstractSwelling, shrinking and physical breakdown processes are reviewed with reference to well-known mudrock and overconsolidated clay formations in the UK and USA. Swelling results from two processes: the equilibration of depressed porewater pressures following stress relief, and the physico-chemical (osmotic) response of component clay minerals. Expansion in Na-smectite, and to a lesser extent Ca-smectite, clays is governed by double-layer swelling, whereas in kaolinites it is purely a mechanical unloading phenomenon; illites show an intermediate response. Intraparticle swelling in mudrocks older than the Silurian in the UK, or Upper Mississippian in the USA, can be expected to be reduced because of the removal of expandable layers by burial diagenesis. Shrinkage, like mudrock breakdown, is restricted to the partly saturated zone. Suction pressure-moisture content curves of indurated mudrocks are shown to be different from mudrocks and clays with high proportions of expandable clay minerals. Classification of expansion potential based on activity ratio poses problems with indurated types, but with some modification of method reasonable predictions can be made. Controls on physical disintegration are identified as: (i) incidence of sedimentary structures and discontinuities, (ii) slaking (air breakage), (iii) expandable clay mineral content, especially smectite, and (iv) clay mineral fabric orientation. Exceptionally high exchangeable sodium percentages have been measured in Coal Measures rocks susceptible to breakdown.
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Yi-Kai, Geng, Jin Zhen-Kui, Zhao Jian-Hua, Wen Xin, Zhang Zhen-Peng y Wang Yang. "Clay minerals in shales of the Lower Silurian Longmaxi Formation in the Eastern Sichuan Basin, China". Clay Minerals 52, n.º 2 (junio de 2017): 217–33. http://dx.doi.org/10.1180/claymin.2017.052.2.04.
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AbstractThe present study examines the characteristics of clay minerals in shale gas reservoirs and their influence on reservoir properties based on X-ray diffraction and scanning electron microscopy. These analyses were combined with optical microscopy observations and core and well-log data to investigate the genesis, distribution characteristics, main controlling factors and pore features of clay minerals of the Lower Silurian Longmaxi Formation in the East Sichuan area, China. The clay mineral assemblage consists of illite + mixed-layer illite-smectite (I-S) + chlorite. This assemblage includes three sources of clay minerals: detrital, authigenic and diagenetic minerals. The lower section of the Longmaxi Formation in the Jiaoshiba area has sealing ability which resulted in abnormal high pressures during hydrocarbon generation which inhibited illitization. Therefore, an anomalous transformation sequence is present in which the mixed-layer I-S content increases with depth. This anomalous transformation sequence can be used to infer the existence of abnormal high pressures. The detrital components of the formation also affect the clay-minerals content indirectly, especially the abundance of K-feldspar. The transformation of mixed-layer I-S to illite is limited due to the limited availability of K+, which determines the extent of transformation. Three types of pores were observed in the shale reservoir rocks of the Longmaxi Formation: interparticle (interP) pores, intraparticle (intraP) pores and organic-matter pores. The clay-mineral content controls the development of intraP pores, which are dominated by pores within clay particles. For a given clay mineral content, smectite and mixed-layer I-S were more conducive to the development of shale-gas reservoirs than other clay minerals.
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Williams, Lynda B. "Geomimicry: harnessing the antibacterial action of clays". Clay Minerals 52, n.º 1 (marzo de 2017): 1–24. http://dx.doi.org/10.1180/claymin.2017.052.1.01.
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AbstractA decade of research on clays that kill human pathogens, including antibiotic-resistant strains such as methicillin-resistant S. aureus (MRSA), has documented their common characteristics. Worldwide, ∼5% of clays tested to date are antibacterial when hydrated. Most antibacterial clays are from hydrothermally altered volcanics, where volcanogenic fluids produce minerals containing reduced metals. Ferruginous illite-smectite (I-S) is the most common clay mineral, although kaolins dominate some samples. Antibacterial clay mineral assemblages may contain other reduced Fe minerals (e.g. pyrite) that drive production of reactive oxygen species (H2O2, •OH, •O2−) and cause damage to cell membranes and intracellular proteins. Ion exchange can also cause loss of bacterial membrane-bound Ca2+, Mg2+ and PO43–.Critically important is the role of clays in buffering the hydration water pH to conditions where Al and Fe are soluble. A nanometric particle size (<200 nm) is characteristic of antibacterial clays and may be a feature that promotes dissolution. Clay interlayers or the lumen of tubular clays may absorb reduced transition metals, protecting them from oxidation. When the clays are mixed with deionized water for medicinal applications, these metals are released and oxidized.Different antibacterial clays exhibit different modes of action. The minerals may be a source of toxins, or by adsorption may deprive bacteria of essential nutrients. In the field, the pH and Eh (oxidation state) of the hydrated clay may help to identify potential antibacterial clays. If the pH is circum-neutral, toxic metals are not soluble. However, at pH < 5 or >9 many metals are soluble and the oxidation of transition metals increases the Eh of the suspension to >400 mV, leading to bacterial oxidation.Understanding the antibacterial mechanism of natural clay may lead to design of new treatments for antibiotic-resistant bacteria, with potential applications in wound dressings, medical implants ( joint replacements, catheters), animal feed stocks, agricultural pathogens, and production of antibacterial building materials. This research exemplifies how ‘geomimicry’ (copying geochemical processes) may open new frontiers in science.
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Warren, E. A. y B. Ransom. "The Influence of analytical error upon the interpretation of chemical variations in clay minerals". Clay Minerals 27, n.º 2 (junio de 1992): 193–209. http://dx.doi.org/10.1180/claymin.1992.027.2.05.
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AbstractUnderstanding the chemical variability of clay minerals depends on the analytical reliability of the techniques used. Uncertainties in clay mineral compositions were computed for common sources of analytical error such as those that arise from contaminant phases present in clay size-fractions in concentrations below the detection limit of routine XRD screening techniques, and the analytical limits of precision for TEM/AEM analysis. When plotted on standard diagrams used to represent clay mineral compositions, the calculated error envelopes were found to be of significant size, such that analyses of pure illites and pure smectites straddled the field for mixed-layered illite-smectites. In addition, on some diagrams random analytical errors resulted in linear trends identical to those caused by mixtures of two or more clay minerals. It follows that variations in the compositions of clay minerals reported in the literaure do not always necessarily represent the actual chemical variation of the minerals. As a result, current interpretations of clay compositional variations may not be as definitive as hoped.