Formation Of Kaolinite Research Articles

Patterns and origins of the porosity in the productive reservoirs of the upper part of the Chubut Group, southern flank of the Golfo de San Jorge Basin, Patagonia Argentina

The Mina del Carmen, Bajo Barreal and Cañadón Seco Formations bear the most important Cretaceous reservoirs in the southern flank of the Golfo de San Jorge Basin, in which the porosity is mainly secondary in origin. Primary porosity is about 4% in average and can be divided in intergranular and intercrystalline porosity, the former is better preserved where chlorite rim cement is abundant, and the second occurs among crystals of the clay cement (main kaolinite). Secondary porosity comprises dissolution of feldspar, ductile fragments, clay cements, lithic grains, and carbonate-zeolite cements.Dissolution of feldspar produces the formation of authigenic kaolinite and secondary porosity; this mechanism dominates in the western area of the southern flank due to sandstones show higher amounts of plagioclase grains, which were very reactive to diagenetic dissolution. Ductile fragments, composed of tuffaceous mudstones (probably of intrabasinal origin), were strongly deformed during the compaction reducing the primary porosity and closing the pore system. Nevertheless, in sandstones containing similar proportions of intrabasinal and extrabasinal clasts, some ductile grains suffered massive dissolution increasing the secondary porosity. Another source of secondary porosity comprises the dissolution of tuff fragments, and locally, carbonate and zeolite cements.The secondary porosity includes the types redistributional (RDS) and pervasive (PVS). This division can be related to previous diagenetic model for the Bajo Barreal Formation. In this way, redistributional secondary porosity is linked to the first and the second events of diagenetic dissolution, while the pervasive secondary porosity to the third dissolution event, which likely had a telogenetic origin.

The effect of modified Cu(II) kaolinite on interactions with rubberizing components

The interactions of modified Cu(II) kaolinite with rubberizing components, such as stearic acid (SA), zinc oxide (ZnO), sulphur (S) and benzothiazole (Btz) after heating to 150 °C cure temperature were investigated. More over the given prepared modified kaolinite was used for investigation of its effect in model rubber composites. Commercially calcined kaolinite (Kaol) was chemically treated using 0.5 M copper acetate solution in presence of NaOH solution. The modified resulting sample was designated as KCu sample. Different techniques such as Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction patterns analysis (XRD), thermogravimetry/differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM) were used to characterize kaolinite and KCu samples. The different techniques (mainly FTIR an XRD) demonstrated that the copper acetate treatment of kaolinite resulted in formation of monohydrate copper hydroxy acetate complex, which influenced the clay surface. XRD pattern and FTIR spectrum of the modified KCu proved that copper acetate treatment did not affect the clay structure significantly. High-temperature X-ray diffraction patterns analysis (HTXRD) was also used for investigate the interactions of modified KCu with rubberizing components. Heating process of KCu and SA without or with ZnO caused the formation of copper stearate and zinc stearate respectively and it let to the occurrence of the stretching vibrations of the carboxyl group (νCOO−). K-Cu2(OH)3Ac·H2O complex on the clay surface influenced the mutual interaction with benzothiazole and it can be seen in IR spectra involving stretching vibrations (νCH) of aromatic ring and the stretching vibrations of functional groups ν(N=CS) and ν(C=N). Finally, for the supplementation of the results, the model rubber composites, filled with kaolinite and KCu and ranged 5, 10 and 20 phr, were prepared. The effect of modified kaolinite on the curing characteristics (minimum torque – ML, maximum torque – MH, optimal vulcanization time – t90, coefficient of vulcanization rate – Rv) and mechanical properties (tensile strength at break – TSb, elongation at break – Eb and hardness) in sulphur-cured natural rubber (NR) composites was investigated. A low viscosity of the NR compounds was achieved throughout the kaolinite and KCu fillers used. The cure time increased by KCu dosing in amount of 10 and 20 phr. The decrease of the maximum torque (MH) value indicates a lower stiffness as well as the viscosity of the mixture at the end of vulcanization. However, the mechanical properties of the vulcanizates with KCu showed significant improvement of TSb and Eb, compared with standard and mixtures with non-modified kaolinite. The modified Cu(II) form of kaolinite had positive effect on the properties of rubber compounds in amount of 5 and 10 phr.

Mineralogy and genesis of Planosols under a semi-arid climate, Borborema Plateau, NE Brazil

Planosols, such as those found on the Borborema Plateau, NE Brazil, form an important class of moderately weathered soils that support subsistence agriculture in underdeveloped regions of Africa, Asia, and South America. Despite its socioeconomic importance, the genesis of this soil class has not yet been fully elucidated. This study was conducted with the aim of improving knowledge about the genesis of Planosols under a semi-arid climate. Three Planosol profiles on the Borborema Plateau in NE Brazil were collected, classified, and described morphologically, and the main physical and chemical attributes, the pedogenetic forms of iron oxides, and the mineralogical compositions of the sand, silt, and clay fractions were determined. The results indicate that: (a) parent materials richer in feldspar and biotite favor the formation of Planosols with a higher clay content; (b) the dissolution of primary minerals and the formation of clay minerals (known as the argillation process) are fundamental for the genesis of Bt horizons; (c) depth-drainage deficiency leads to hydromorphism, an associated gray color, and the formation of mottles; and (d) monosialitization and bisialitization processes (kaolinite formation and the formation of 2:1 clay minerals, respectively) prevail in Planosols located within landscape positions that have good and poor drainage, respectively. In addition, the present study shows that Planosols under a semi-arid climate can have a clay fraction consisting predominantly of kaolinite, and mineralogical alteration pathways similar to those described in soils under an analogous climate and geology in Northwest Africa; this refutes classical theories that soils with 2:1 clay minerals prevail in warmer and drier regions. This study thus provides greater knowledge about the attributes of Planosols in dry and poor regions and can be used as a reference in studies on the sustainable use and management of such soils.

Diagenesis and reservoir quality of sandstones in the Eocene Shahejie Formation, Raoyang Sag (Jizhong Depression), Bohai Bay Basin, China

Deeply buried (3.5–4.5 km) fan deltaic and braided deltaic sandstones of the Eocene Shahejie Formation are important hydrocarbon reservoirs in the Raoyang Sag of the Bohai Bay Basin (North China). An integrated approach incorporating petrophysics, thin‐section petrography, scanning electron microscope (SEM), cathodoluminescence (CL), and well log analysis was applied to investigate diagenesis, diagenetic minerals, and their impacts on reservoir quality. The sandstones of the Sha‐3 (the third Member of the Shahejie Formation) are dominated by lithic arkoses and arkoses with a low‐moderate compositional maturity and a moderate textural maturity. The pore systems are dominated by secondary pores resulting from dissolution of framework grains, micropores among authigenic clays, and minor amounts of primary intergranular pores. Chemically unstable framework grains such as feldspar and lithic fragments experienced alteration and resulted in formation of authigenic kaolinite. Dissolution and alteration of feldspars and rock fragments and pressure solution of detrital quartz grains were the main sources for quartz cements. Mechanical compaction and cementation by calcite, dolomite, quartz, kaolinite, and mixed‐layer illite/smectite destroyed primary pores, whereas dissolution of framework grains generated secondary pores. Five types of diagenetic facies are identified based on framework mineralogy, texture, diagenetic minerals, and pore systems. These comprise the following: (a) quartz‐cemented sandstone, (b) tightly compacted sandstone, (c) carbonate‐cemented sandstone, (d) clay‐mineral‐cemented sandstone, and (e) clean dissolved sandstone. Diagenetic processes and evolution sequences for the five diagenetic facies were reconstructed based on textural relationships from thin section, SEM, and CL studies. The reservoir quality evolution of various diagenetic facies is predicted by considering variations in grain size, sorting, shape, and matrix content of sandstones. This work, which investigates the diagenetic sequence of sandstones, will provide insights into reservoir quality prediction for low‐permeability sandstones with similar tectono‐depositional settings.

Characteristics and distribution of clay minerals and their effects on reservoir quality: Huagang Formation in the Xihu Sag, East China Sea Basin

The characteristics and distribution of clay minerals and their effects on reservoir quality in the Huagang sandstones in the Xihu Sag, East China Sea Basin were studied by using X-ray diffraction, casting thin-sections, scanning electron microscopy, electron microprobe analysis, fluid inclusion analysis, constant-rate mercury injection and nuclear magnetic resonance. Clay minerals consist of kaolinite, chlorite, illite and illite–smectite mixed layer (I/S); kaolinite forms from dissolved feldspars, chlorite occurs as clay coatings that are transformed from clay precursors owing to the flocculation of suspended detrital clays or the crystallisation of pore fluids, and illite forms from the illitisation of detrital smectite, authigenic kaolinite and K-feldspars. Clay distribution is controlled by sedimentary environments, burial history and lithologies. Typical reservoirs in the western sub-sag are thin and developed in braided river facies at relatively shallow burial depths with clays dominated by kaolinite. However, typical reservoirs in the central inversion tectonic zone are thicker and developed in a braided delta front facies at deeper burial depths with clays mainly consisting of chlorite, illite and I/S. High-quality reservoirs are characterised by coarse granularity, high quartz content and low clay content with widespread development of chlorite coatings that inhibit quartz cements at low temperatures. At higher temperatures, the high-quality reservoirs develop more pores providing growth space for quartz cements and result in the coexistence of chlorite coatings and quartz cements. The high-quality reservoirs are controlled by their lithological characteristics rather than chlorite coatings. Illite and I/S clays create severe damage to reservoirs by reducing the size and connectivity of pore-throats.

Pore-fluid-dependent controls of matrix and bulk thermal conductivity of mineralogically heterogeneous sandstones

For a variety of geothermal engineering applications, the only indirectly determinable matrix thermal conductivity (λm) is frequently used to convert the measured bulk rock thermal conductivity (λb) of air-saturated sandstones to water-saturated conditions. However, the necessary assumption that the absolute value of λm remains constant irrespective of the pore fluid present turns out to be not valid in practice and the explicit control factors on λm have not been demonstrated yet for different pore fluids. A pore fluid-controlled change in the λm value also questions the transferability of empirical proxy models for the estimation of water-saturated λb when they were calibrated on air-saturated samples. This study applies a multiple regression analysis to quantitative mineralogical composition data and porosity (Φ) to identify the controls of the λm for different types of pore fluids (water- vs. air-saturation). In addition, the differences in the calculated λm values resulting from different calculation methods or input data (theoretical geometric mean model or mineralogical composition data) are examined. We further test the suitability of different sandstone properties as potential proxies for the estimation of the λb, with respect to the pore fluid type. Differences in the absolute value of λm of sandstones from different measurement conditions (air- or water-saturated) are most probably related to the formation of authigenic kaolinite in the pore space, originating from the alteration of alkali feldspar. In addition, the thermal properties of the rock matrix are mainly controlled by the volume fractions of the high thermally conductive mineral fractions quartz and dolomite. Empirical models that have solely Φ or P-wave velocity (vp) as variables are not suitable for the prediction of water-saturated λb of sandstones. Instead, quantitative mineralogical data of high thermally conductive mineral phases such as quartz and dolomite have to be included. The easily measureable vp is proposed as a promising proxy for both pore fluid types tested: combined with the total quartz volume/porosity ratio for air-saturated sandstones, and combined with the quartz plus dolomite volume fractions for water-saturated sandstones.

Analysis of rock alteration in a hydropower engineering project, southeastern China

The characteristics of rock and mineral alteration of a rock mass related to a hydropower engineering project in southeastern China are analyzed and presented. Rock mass alteration is an important engineering geology challenge in the region; in this study, it is shown that the main types of alteration are albitization and formation of clay minerals. The main minerals in the altered rocks are plagioclase, K-feldspar, montmorillonite, illite, and kaolinite and the alteration processes were tracked using the interrelationships between K, Na, Ca, and loss on ignition during formation of illite, montmorillonite, and kaolinite. Laboratory testing of rock physical properties showed that water content, natural water absorption, and saturated water absorption in the altered rocks all gradually increase as the degree of alteration increases. However, rock mass density shows a decreasing trend with increasing alteration, and the degree of alteration exerts little influence on rock particle density. Rock disintegration tests show that the disintegration index decreases as alteration deepens.

Preparation of azobenzene-intercalated kaolinite and monitoring of the photoinduced activity

AbstractSystems consisting of layered structures and photoactive molecules have been studied extensively. The structures of resulting complexes may be controlled by UV–Vis radiation, which subsequently affects their materials properties. This study describes a synthesis route for obtaining a photoresponsive kaolinite intercalation compound. The material was prepared by co-intercalating azobenzene and benzylalkylammonium chlorides into a methoxy form of kaolinite. The resultant materials possessed large basal spacing values in the range of 45–55 Å. The UV–Vis and Fourier-transform infrared spectroscopy analyses confirmed the reversible photoisomerization of azobenzene upon exposure to UV and Vis radiation. This phenomenon was significantly influenced by the type and amount of co-intercalated molecules. Upon multiple trans–cis conversions, the azobenzene partially evaporated. For the first time, a kaolinite-based material was prepared that exhibited photochromic behaviour upon UV and Vis irradiation.

Neocrystallization of clay minerals in the Alhama de Murcia Fault (southeast Spain): implications for fault mechanics

AbstractTwo preferred textures were observed in the Alhama de Murcia Fault rocks: (a) foliated bands (>100 µm thick) rich in well-crystallized dioctahedral micas, quartz, hematite and dolomite; and (b) ultrafine-grained bands (<100 µm thick) made of patches composed of small mica crystals (<15 µm) and dispersed Fe-oxides. In both textures, kaolinite forms intergrowths or patches of randomly oriented crystals filling gaps or opening layers of presumably inherited detrital mica crystals, which is interpreted as an epitaxial growth from fluids. The Na/K ratio of mica crystals in the thin ultrafine-grained bands shows a wider range than the micas from the foliated bands including muscovitic, intermediate Na/K and paragonitic compositions. The absence of the 0.98 nm intermediate peak in the diffractograms indicates that the small micas are submicroscopically paragonite and phengite intergrowths. The d001 values of the K-dioctahedral micas in the <2 µm and whole fractions are clearly different from each other. The d001 values of micas of the <2 µm fraction are larger, indicating a higher K and lower Na content in the small micas. Their composition corresponds to lower temperatures, suggesting their growth during a genetic episode in the fault. The textural relationships indicate a late growth of kaolinite, probably due to the fluid–rock interaction along fault planes and fractures. The neoformed clay minerals might alter the stability of the fault plane. The absence of expandable clay minerals and the relatively high frictional strength of kaolinite under wet conditions might explain the observed velocity-neutral behaviour of this gouge and earthquake propagation towards the surface.

Chemical, physical, thermal, textural and mineralogical studies of natural iron ores from Odisha and Chhattisgarh regions, India

The chemical, physical, thermal and texture properties of iron ores from different regions of Odisha and Chhattisgarh regions, India, have been investigated to understand the compositional variations of Fe, Al2O3, SiO2, S and P. They were analyzed for its susceptibility to meet the industrial requirements, for various iron manufacture techniques. Chemical analysis indicated that the majority of the iron ores is rich in hematite (> 90 wt%), poor in gangue (<4.09 wt% SiO2 and <3.8 wt% Al2O3) and deleterious elements (P<0.065 wt% and S<0.016 wt%) in all these iron ores found to be low. XRD peaks reviled that the gangue is in the form of kaolinite and quartz, and same was observed in Fourier transform infrared (FTIR) spectroscopy in the range of 914 to 1034 cm–1. The iron ores were found to have excellent physical properties exemplify with tumbler index (82 wt%–91 wt%), abrasion index (1.27wt%–4.87 wt%) and shatter index (0.87wt%–1.64 wt%). FTIR and thermal analysis were performed to assimilate the analysis interpolations. It was found that these iron ores exhibit three endothermic reactions, which are dehydration below 447 K with mass loss of 0.13 wt% to 1.7 wt%, dehydroxylation at 525–609 K with mass loss of 1.09 wt%–4.49 wt% and decomposition of aluminosilicates at 597–850 K with mass loss of 0.13 wt%–1.15 wt%. From this study, we can conclude that due to its excellent physico-chemical characteristics, these iron ores are suitable for BF and DRI operations.

Alterations of geochemical properties of a tight sandstone reservoir caused by supercritical CO2-brine-rock interactions in CO2-EOR and geosequestration

The geochemistry of a reservoir is of great significance for CO2 Enhanced Oil Recovery (CO2-EOR) and CO2 geosequestration operations. However, due to the massive diversity in mineralogy and physicochemistry of different reservoirs, the current data base is not yet sufficient to conclusively determine the alterations of geochemical prosperities when CO2 is injected especially for tight reservoirs. The attention of this work was given to a tight sandstone reservoir in Lucaogou formation of Jimsar sag (China). The interactions of reservoir rocks, formation brine and supercritical CO2 were extensively investigated under reservoir conditions (75 °C and 32 MPa) aiming to reveal possible mechanisms behind. The results showed that the dissolution of supercritical CO2 in the brine created an acidic environment (solubility = 0.94 mol/Kg), which induced the dissolution of minerals into the brine and their subsequent precipitation. The primary precipitants in this work were found to be iron minerals and kaolinite, as evidenced by Scanning Electron Microscopy and Energy Dispersion Spectrum (SEM-EDS) analyses. Moreover, the SEM-EDS observations have shown clear signs of mineralogical changes of the rocks with the preferred dissolution of K-feldspar, albite and ankerite. Kaolinitation due to the corrosion of K-feldspar and albite occurred during the CO2-exposure experiments. The mineral surface after exposure to CO2 was altered to be more water-wet as a result of mineral dissolution, kaolinite formation and surface corrosion.

Rare aluminium phosphates and sulphates (APS) and clay mineral assemblages in silicified hydraulic breccia hosted by a Permian granite (Velence Mts., Hungary) as indicators of a high sulfidation type epithermal system

Uncommon micrometer-sized aluminium phosphates and sulphates of the alunite supergroup (APS minerals) associated with clay minerals were found in a polymictic Permian granite hosted hydrothermal breccia in the Velence Mts. (Hungary). The mineral assemblage was studied with TEM, XRD, EMPA and FTIR with the aim of revealing the formation conditions and the genetic link to the hydrothermal processes that affected the granite host. Two breccia types were identified in the granite. In a polymictic, strongly silicified breccia type zoned plumbogummite was found in association with rolled tube-shaped halloysite and kaolinite. Calcium, barium and lead zonation of the plumbogummite and the Cl and S contents of the halloysite indicate the hypogene origin of this assemblage. Kaolinite, halloysite and plumbogummite form under acidic conditions at temperatures ≤150 °C in hydrothermal systems. APS minerals belonging to the woodhouseite solid solution series (s.s.s.) were detected in the matrix of argillic polymictic breccia beside the alunite in a kaolinite/dickite, illite rich matrix. Alunite and woodhouseite form under acidic conditions in hydrothermal systems. Kaolinite/dickite and illite also suggest acidic conditions and temperatures of ≥240 °C. The close vicinity of the studied breccias to hydrothermal centres hosted by Palaeogene andesitic volcanic series, the strike of the studied breccia veins as well as the similarities in the mineral assemblages imply that the brecciation is spatially and genetically related to the high-sulfidation epithermal systems of the Palaeogene magmatic-hydrothermal activity. In our model, strongly acidic and hot hydrothermal fluids entered into the granite along E-W trending faults that resulted in silicification, brecciation and the formation of APS minerals in association with clay mineral assemblages.

Extraction of ions of zinc and copper by modified kaolinite forms

A study was made on the extraction of zinc and copper ions by modified forms of kaolinite. The quantitative characteristics of the adsorption of zinc and copper ions are obtained. It is shown that kaolinite after alkaline and salt treatment increases the exchange capacity with respect to zinc and copper ions. The adsorption equilibrium was described using Langmuir and Freundlich models. The degree of extraction of zinc and copper ions from solutions was determined depending on their concentration at a constant mass of the adsorbent. It is shown that when kaolinite is modified by solutions of sodium chloride and sodium hydroxide, the adsorption capacity with respect to zinc and copper ions increases.

Fluid-rock interaction and dissolution of feldspar in the Upper Triassic Xujiahe tight sandstone, western Sichuan Basin, China

Abstract Secondary porosity in the Upper Triassic Xujiahe tight sandstone of the western Sichuan Basin is mainly the product of feldspar dissolution. In the Xu-4 Member, the upper reservoir of the Xujiahe Formation, feldspars are dissolved to a significant extent and observations indicate that nearly all feldspars have been dissolved completely, with only 1.73% content of feldspar remaining. In the Xu-2 Member, the lower reservoir, feldspars are well preserved; the current content of feldspar is 12.54% on average, and the secondary porosity derived from feldspar dissolution is less than 1%. Kaolinite occurs almost exclusively in the Xu-4, but it is nearly absent in the Xu-2. The K+ content in the Xu-2 is 3.3 times higher than that in Xu-4. The K+/H+ ratio in the Xu-2 is also higher than that in the Xu-4. These differences between the two reservoirs can be attributed to their distinguishing fluid-rock systems. The low K+ content and relatively high δ18O in the Xu-4 formation water are the result of intensive fluid-rock interaction in an open fluid-rock system. The upper Xu-4 is close to the overlying coal-measures of the Xu-5 from which organic acid flowed into the Xu-4. Meanwhile, K+ contained in sandstone migrated out to the mudstones. The resulting low K+/H+ ratio in the formation water of the Xu-4 was responsible for almost all the feldspar dissolution and kaolinite formation. In contrast, due to the relatively closed fluid-rock system in the Xu-2, K+ did not migrate into adjacent rocks and acidic fluids did not invade, which led to K+-rich formation waters maintaining a high K+/H+ ratio. Hence, K-feldspar was well preserved and kaolinite was completely transformed into illite. Therefore, in contrast to the Xu-2 tight sandstone, the Xu-4 sandstone has relatively higher secondary porosity, which favours the formation of better quality reservoirs.

Determination of the Settling Rate of Clay/Cyanobacterial Floccules

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction of clay particles with reactive, planktonic cyanobacterial cells to the sedimentary record is under studied. This interaction is a potentially major contributor to shale depositional models. Within a lab setting, the flocculation and sedimentation rates of these materials can be examined and measured in a controlled environment. Here, we detail a protocol for measuring the sedimentation rate of cyanobacterial/clay mixtures. This methodology is demonstrated through the description of two sample experiments: the first uses kaolin (a dehydrated form of kaolinite) and Synechococcus sp. PCC 7002 (a marine coccoid cyanobacteria), and the second uses kaolin and Synechocystis sp. PCC 6803 (a freshwater coccoid cyanobacteria). Cyanobacterial cultures are mixed with varying amounts of clay within a specially designed tank apparatus optimized to allow continuous, real-time video and photographic recording. The sampling procedures are detailed as well as a post-collection protocol for precise measurement of chlorophyll a from which the concentration of cyanobacterial cells remaining in suspension can be determined. Through experimental replication, a profile is constructed that displays sedimentation rate.

Determination of the Settling Rate of Clay/Cyanobacterial Floccules.

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction of clay particles with reactive, planktonic cyanobacterial cells to the sedimentary record is under studied. This interaction is a potentially major contributor to shale depositional models. Within a lab setting, the flocculation and sedimentation rates of these materials can be examined and measured in a controlled environment. Here, we detail a protocol for measuring the sedimentation rate of cyanobacterial/clay mixtures. This methodology is demonstrated through the description of two sample experiments: the first uses kaolin (a dehydrated form of kaolinite) and Synechococcus sp. PCC 7002 (a marine coccoid cyanobacteria), and the second uses kaolin and Synechocystis sp. PCC 6803 (a freshwater coccoid cyanobacteria). Cyanobacterial cultures are mixed with varying amounts of clay within a specially designed tank apparatus optimized to allow continuous, real-time video and photographic recording. The sampling procedures are detailed as well as a post-collection protocol for precise measurement of chlorophyll a from which the concentration of cyanobacterial cells remaining in suspension can be determined. Through experimental replication, a profile is constructed that displays sedimentation rate.

Assessment of landfills vulnerability on the groundwater quality located near floodplain of the perennial river and simulation of contaminant transport

This investigation was carried out with the objective to understand the impacts of landfill leachate on groundwater quality. This study also explained the movement of trace metals in groundwater by using Visual MODFLOW/MT3D. It also delineates the various factors controlling the suitability of groundwater for domestic, agriculture and drinking purpose. The statistical assessment shows ~ 60.09% groundwater are in good condition, ~ 35.38% in poor condition and 4.53% in very poor condition. The spatial distributions of water quality index (LWQI) around landfills indicate landfills are in depleted condition. Hydrogeochemical classification indicates ~ 90.91% groundwater shows Ca–Na water-type cation facies and Cl− water-type anion facies. While 9.09% groundwater shows Ca–Na water-type cation facies and Cl−–SO42−–HCO3− anion hydrogeochemical facies. The mineral equilibrium diagram of groundwater has revealed that it is in equilibrium with silicate minerals and favors kaolinite formation. The saturation index indicates chrysotile (Mg3Si2O5(OH)4) (2.84), dolomite (CaMg(CO3)2) (0.45), ferric hydroxide (Fe(OH)3) (1.97–3.58), goethite (FeOOH) (7.86–9.47), hematite (Fe2O3) (17.73–20.95), hydroxyapatite (Ca5(PO4)3OH) (2.38–4.62), jarosite-K (KFe3(SO4)2(OH)6) (0.22–1.92), cerussite (PbCO3) (0.39), vivianite (Fe3(PO4)2·8H2O) (0.39) and willemite (Zn2SiO4) (0.35) are reactive mineral in groundwater aquifer of study area. The seasonal and temporal variation indicates anthropogenic influence. The calibration and validation of model show > 90% models correct with 95% confidence. The contaminant transport simulated in groundwater aquifer with the high accuracy (estimated standard error 0.049 m) for the large area (~ 300 km2). The trends of contour lines of trace metals concentration indicate; it will contaminate study area within few years of its release through the landfill.

A Qualitative Study of Airborne Minerals and Associated Organic Compounds in Southeast of Cairo, Egypt

This study is concerned with the identification of the mineralogical composition of dust fall samples collected from southeast of Cairo, Egypt. The mineralogical identification was conducted by means of the polarizing microscope, infra-red spectroscopy (IR), and X-ray diffraction (XRD). The relationship between the mineralogical composition of dust fall samples and 10 rock samples from the surrounding terrains were investigated. The major mineralogical species existing in the atmosphere of the study area are: carbonates mainly in the form of calcite in addition to the appearance of the dolomite form in traces overall the study area, but with considerable observation in the southern region; quartz which is less than calcite in its abundance; sulphates in the form of gypsum which may also be present as traces in the anhydrite form. Trace constitution of feldspars; clay minerals in the form of kaolinite, illite, and montimorillonite; and halite are also observable in the same samples. Organic compounds are present in the atmosphere of the area mainly as alkanes with presence of traces of phosphines. This study qualitatively shows the mineralogy of air particulate over rock processing area and the obtained results indicates that the main pollution source in the study area is the industrial activities with minor contribution of the natural sources, especially erosion and dust carried by winds from the surrounding terrains Cairo in the southern direction. This study provides useful results for the contribution of rock processing activities to the mineral composition of atmospheric particulates.

Alteration parameters affecting the Luxor Avenue of the Sphinxes-Egypt

Stone alteration in the environment is caused by various extrinsic disintegration agents, besides, their intrinsic properties “mineralogical composition, textures and internal structure”. Therefore, the purpose of the current study was to evaluate the weathering state affecting the Luxor Avenue of the Sphinxes by studying its chemical, mineralogical and physio-mechanical characteristics, in addition to morphological features. Scientific techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD), Petrographical microscopy (PM), Cathodoluminescence (CL), Environmental Scanning Electron Microscope (ESEM) and micro energy-dispersive X-ray fluorescence (μ-EDXRF) were used. The results showed that quartz represents more than 96% of the sandstones and the main cement of the grains is quartz overgrowth. Alteration and formation of kaolinite was clearly observed. Halite, sylvite and bischofite were the main salts that affected the statues representing approx. 78.40%. The study also provided information about the different deterioration factors affected the Avenue of the Sphinxes namely; burial environment, solar effects, soil moisture and groundwater. These caused some deterioration forms such as soiling & crusting, breaking down most of the statues heads, saturation forms, salt crystallizations and stone abrasion. Cleaning, desalination and consolidation using different materials and techniques, in addition to reducing the human anthropogenic impacts are recommended for future conservation of the Luxor Avenue of the Sphinxes.

Integrated study of Red Mediterranean soils from Southern Italy

Terra Rossa is a typical Mediterranean soil characterized by an association of the Mediterranean climate, high internal drainage (due to the karstic nature of the underlying hard limestone) and neutral pH conditions. The genesis of this soil is a controversial subject in terms of the origin of the parent material, from the residual underlying (carbonate/dolomite) bedrock and/or from external (aeolian dust) contributions. We apply an integrated approach (chemical, physical, mineralogical and geochemical) to nine soil profiles of terra rossa from Apulia region (southern Italy), in order to investigate the main soil properties relating to soil weathering and pedogenetic processes, as well as to acquire knowledge on soil-bedrock relationships and their origin. Results showed that these terra rossa were generally clayey, had colors (moist) ranging from 2.5YR to 7.5YR Munsell hues and a mineralogical composition of mainly kaolinite, illite/mica and Fe-oxides (hematite and goethite). The pedogenetic indices (Feo/Fed, Fed/Fet) exhibited a generally high degree of crystallinity of iron forms and soil weathering. The correlation between illite/kaolinite ratio and pedogenetic indices, as well as that of kaolinite and hematite with the Feo/Fed ratio indicated that weathering processes in the studied environments promoted the formation of both kaolinite and hematite from illite/mica minerals. Since the hematite/goethite ratio was generally higher than 1, rubification processes also occurred in these soils. The comparison of the geochemical composition of terra rossa with that of insoluble residues (obtained from the underlying limestone and dolomite rocks) indicated that a group of elements (such as Ti, Mn, Th) was more concentrated in terra rossa than in the insoluble residues, whereas another group (made up of Fe, K, Ca, Cr, Cu, Zr, Zn, Rb, Ni, As, Sr and Pb) was more concentrated in the insoluble residues than in terra rossa. The two groups of elements were considered to be different as a result of their having different sources, the first being allochtonous and the second mainly authoctonous. The additional correlation of Ti, Mn and Th with terra rossa clay content seemed to support the hypothesis of wind-blown long distance transport for these elements.