Apatite Minerals Research Articles

Nano zinc oxide and nano bioactive glass reinforced chitosan/poly(vinyl alcohol) scaffolds for bone tissue engineering application

The present study was to develop a hybrid chitosan-based bionanocomposite for potential bone tissue engineering applications. Chitosan (C)/Poly(vinyl alcohol) (P)/nano bioactive glass (B)/nano Zinc Oxide (Z) were fabricated by sol-gel assisted solvent casting method. In this method, several CPBZ nanocomposites have been studied by varying the ratios of nano ZnO (0.05%, 0.1%, 0.2%) to yield CPBZ1, CPBZ2 and CPBZ3 hybrid scaffolds. TEM, FESEM- EDAX, XRD and FTIR analyses were performed to characterize the macrostructure of CPBZ bionanocomposites. Nano ZnO of size 20 nm and nano bioactive glass of size 6–10 nm was synthesized and characterized by TEM analysis. The in vitro bioactivity studies confirmed the formation of apatite minerals that results in direct bone bonding implant. SEM revealed the macroporous structure with a pore size of about 10 µm and hydrophilic rough surface. The phase composition of nano ZnO embedded in CPBZ scaffolds was examined by XRD. The characteristic functional groups and the chemical interactions associated with the organic-inorganic phase were analyzed by FTIR. The results of mechanical studies by a universal testing machine (UTM) demonstrated an increase in the tensile strength and apparent density after the addition of nano bioactive glass and nano ZnO. The integration of nano Zinc Oxide in the polymer matrix increased the swelling ratio up to 298% and maintained the delayed biodegradation behavior around 38%, while the pH remained neutral (7.4). The antibacterial activity evaluated by Salmonella typhi and Enterococcus faecalis pathogens showed a better zone of inhibition for gram positive E. faecalis. The hemocompatibility study proves that the CPBZ nanocomposites are blood compatible and showed a hemolytic ratio of less than 2%. The results demonstrated that the prepared bionanocomposites could act as an extracellular matrix in osteogenic tissue engineering.

Study on Theory of Separation Efficiency of Twin-Spiral Separator in a Grinding-Separation Apatite Process

Study on twin-spiral separator in a grinding - separation apatite process is presented. The evaluation of separation efficiency of the solid - solid separator by gravity sedimentation such as settling tanks or by centrifugal such as cyclone, centrifuge equipment in chemical industry is necessary. This study shows a method to evaluate the separation performance of a separator using the theory of separation efficiency. The method has been applied to the twin-spiral separator in a grinding - separating process at Vietnam Apatite Mineral Processing Company.

Carbonate‐Associated Phosphate (CAP) Indicates Elevated Phosphate Availability in Neoarchean Shallow Marine Environments

AbstractPhosphorus is essential for cell biology, yet scarce in modern marine environments wherein free phosphate is consumed by life or titrated by calcium to form apatite minerals. The environmental conditions under which the early biosphere emerged and phosphorus was integrated throughout biochemistry is yet unknown. We measured the phosphate concentrations of 2.8–2.5 Ga shallow marine carbonate facies across six Neoarchean shelf‐ramp environments. We found that the P/Ca ratios of Neoarchean stromatolites, micrites, and crystal fans were >4‐fold to 12‐fold more enriched in carbonate‐associated phosphate than modern marine coral skeletons and abiotic Phanerozoic carbonates. Our results support the view that Archean productivity was limited by the availability of electrons rather than phosphate or other nutrients, and help explain why phosphorus is so central to the molecules, metabolisms, and bioenergetics observed in cells.

Dentin Biomodification with Flavonoids and Calcium Phosphate Ion Clusters to Improve Dentin Bonding Stability.

The purpose of this study was to evaluate the effects of flavonoids and calcium phosphate ion clusters (CPIC) on dentin bonding stability. Seven experimental solutions were synthesized using icaritin (ICT), fisetin (FIS), silibinin (SIB), CPIC, and combinations of one of three flavonoids and CPIC (ICT + C, FIS + C, SIB + C). The experimental solutions were applied to demineralized dentin prior to the application of a universal adhesive. A group without any experimental solution served as a control. Dentin specimens pretreated with the experimental solutions were assayed using Fourier transform infrared (FTIR) spectroscopy. The microtensile bond strength (µTBS) and nanoleakage were evaluated at 24 h and after 10,000 thermocycles. FIS and ICT + C showed significantly higher µTBS than the control group at 24 h. CPIC, ICT + C, FIS + C, and SIB + C showed significantly higher µTBS than the control group after thermocycling. After thermocycling, silver infiltration into the hybrid layer and interfacial gaps was more noticeable in the control group than in the other groups. The FTIR spectra revealed the formation of apatitic minerals in the demineralized dentin in the flavonoid and CPIC combination groups. The pretreatment of demineralized dentin with flavonoids and CPIC improved dentin bonding stability. The flavonoid and CPIC combinations preserved dentin bond strength.

Arg−Gly−Asp peptide functionalized poly-amino acid/ poly (p-benzamide) copolymer with enhanced mechanical properties and osteogenicity

Poly-amino acid (PAA) is a promising biomaterial in biomedical engineering due to its similar amide bond structure to collagen and excellent biocompatibility, but the lack of osteogenic activity and inferior mechanical strength limit its long-term application in orthopedics. In this study, a poly-amino acid/poly (p-benzamide) (PAA-PBA) copolymer with high mechanical strength was designed and fabricated by the method of solution polymerization. The chain structures, thermal properties and mechanical properties of these polymers were evaluated and results showed that PBA greatly promoted the mechanical properties of PAA, and the copolymer performed the maximum mechanical strengths with compressive strength, bending strength and tensile strength of 123 MPa, 107 MPa and, 95 MPa, respectively. To increase the bioactivity of surface, a bioactive coating that consists of poly-(dopamine) (PDA) nanolayers and tripeptide Arginine-Glycine-Aspartic acid (RGD) on sulfonated PAA-PBA copolymer was created. A porous structure appeared on the surface after modification, the surface roughness and hydrophilicity of copolymer has been improved obviously after introducing PDA and RGD peptide coating. The in vitro bioactivity evaluation demonstrated that the RGD-functionalized sample showed a significantly improved ability to promote bone apatite mineralization, cell adhesion, proliferation and osteogenic differentiation. In a word, such a strategy of material synthesis and surface modification method shows a great potential for broadening the use of PAA in the application of load-bearing bone substitute biomaterials.

Enhancing the bioactivity of hydroxyapatite bioceramic via encapsulating with silica-based bioactive glass sol

Although hydroxyapatite (HA) bioceramic has excellent biocompatibility and osteoconductivity, its high chemical stability results in slow degradation which affects osteogenesis, angiogenesis and clinical applications. Silica-based bioglass (BG) with superior biological performance has been introduced into HA bioceramic to overcome this insufficiency; however, the composite bioceramics are usually prepared by traditional mechanical mixture of HA and BG powders, which tremendously weakens their mechanical performance. In this research, BG-modified HA bioceramics were prepared by the use of BG sol encapsulated HA powders. The results showed that introducing 1 and 3 wt% BG allowed the HA-based bioceramics to maintain the high compressive strength (>300 MPa), improved the apatite mineralization activity, and played an important role in cellular response. The bioceramic modified with 1 wt% BG (1BG/HA) remarkably enhanced in vitro cell proliferation, osteogenic and angiogenic activities. This present work provides a new strategy to improve the biological performance of bioceramics and the HA-based bioceramics with 1 wt% BG can be as a promising candidate material for bone repair.

Origin of the subduction-related Tieli nephrite deposit in Northeast China: Constraints from halogens, trace elements, and Sr isotopes in apatite group minerals

Apatite, which is an excellent tracer of geological processes and magma evolution, can record a variety of information about melt and/or ore-fluid evolution by incorporating large amounts of trace elements. In this study, we conducted an in situ geochemical analysis of apatite from the Tieli nephrite deposit in Northeast China and evaluated the genetic mechanism along with the source. The apatite from the Tieli nephrite deposit in Northeast China is magmatic apatite characterized by positive Ce anomalies, negative or positive Eu anomalies, enrichment in light rare earth elements, depletion in heavy rare earth elements, and high F content. The apatite coincides with plagioclase crystallization with positive Sr-(La/Yb)N/(Sm/Yb)N correlations. The geochemical characteristics of the redox-sensitive elements (Eu, V, As, and Mn) in apatite indicate that the parental magma has a high oxygen fugacity between HM (Hematite–Magnetite) and NNO (Ni-NiO). The estimated F and Cl contents of the source area (average values of 1694 and 2328 ppm, respectively) are higher than the average values of the continental crust and primitive mantle, indicating a convergence process of halogens in the source area. The non-chondritic Y/Ho ratios of the apatite (3.34–53.64) imply that the magma interacted with a high volume of fluids. Combined with the findings of previous studies, the 87Sr/86Sr values in apatite suggest contributions from crust and mantle materials. Moreover, the positive correlation between Sr and 87Sr/86Sr may indicate that the subducted sediments altered by seawater were added into the magma chamber. Based on the above findings, the subduction of the Pacific Plate may supply source material and power for magmatism and mineralization in the Tieli nephrite deposit.

Effectiveness of mesoporous bioglass in drug delivery

Since the invention of bioactive glass 50 years ago, it has become a versatile material used in healthcare in a variety of applications and compositions. Bioactive glass has shown superior capabilities of drug delivery compared to traditional carriers. For example, time-released medications are less likely to reach toxic levels, while delivering a specific, therapeutic dose to a localized area. The objective of this paper is to investigate the properties and effectiveness of mesoporous bioglass (MBG) as a drug delivery carrier. A literature review of various polymer coated 45S5 Bioglass® loaded with vancomycin was analyzed to determine their drug release response. Since MBG continues to be a preferred carrier with numerous combinations; size, coating, doped with ions, medications, and other physical conditions, there is a need to understand more fully their effectiveness. For a given loading efficiency of 5-15% the burst release % for day 1 remained 15-30% for given surface area, pore volume and pore size of 3.5 to 5 nm. The mechanical properties summarized in this paper are compared with the drug release kinetics. In general, for a given fracture toughness and compressive strength, the ratio of Young’s modulus to bending strength around 250 determined poor apatite mineralization resulting in slow release. As this ratio increased the apatite mineralization and dissolution rate increased. Doping MBG with ions enhanced the drug efficacy to treat a particular condition, for example, silver. Polymer coated MBG exhibited slower dissolution rate than uncoated MBG. Dissolution time increased with the drug loading rate, drying time of the coating, multi-layer coats of drug and polymer for the drug studied in this paper to more than 50%.

Impact of geological origin on flotation separation of apatite from dolomite using β-naphthyl sulfonate formaldehyde condensate as depressant

Under the same flotation conditions, the floatability of apatite is different with respect to geological origin. In this study, we tried to establish the relationship between geological origin and the floatability of apatite from the aspect of chemical compositions. Apatite minerals from igneous, sedimentary metamorphic and sedimentary deposits have been selected for flotation tests and a series of analyses including zeta potential tests, adsorption measurements and XPS analysis. β-naphthyl sulfonate formaldehyde condensate (NSFC) was used as the depressant in this work owing to its low cost as well as its excellent selectivity towards dolomite mineral. The flotation results demonstrate that NSFC showed a strong affinity towards dolomite rather than apatite. However, under the same flotation conditions, the floatability of apatite is highly affected by geological origin. The floatability always follows this given order: sedimentary apatite＞igneous apatite＞sedimentary metamorphic apatite. Combined with the results obtained from zeta potential measurements and XPS analyses, the adsorption of NSFC on these apatite surface is specific adsorption. Moreover, the larger amount of replacement of calcium by iron on apatite surface could result in a stronger formation of chemical bonds between iron elements and sulfo groups, thereby enhancing the hydrophilicity of apatite and consequently reducing its floatability in response.

Preparation of osteoinductive – Antimicrobial nanocomposite scaffolds based on poly (D,L-lactide-co-glycolide) modified with copper – Doped bioactive glass nanoparticles

The aim of this study was to explore the preparation of porous nanocomposite scaffolds with simultaneous osteogenic – antibacterial properties by incorporating copper – doped bioactive glass nanoparticles into Poly (D,L-lactide-co-glycolide) lactide:glycolide. Bioactive glass nanoparticles were synthesized by using sol–gel technique from the SiO2 – P2O5 – CaO – Na2O – CuO system. Poly (D,L-lactide-co-glycolide) lactide:glycolide nanocomposite scaffolds with different nanoparticle contents were prepared by combined lyophilization/salt leaching. The in vitro bioactivity of the scaffolds was assessed in simulated body fluid, and cell viability and osteogenic differentiation assays were performed with stem cells. Antibacterial activity of the materials was assessed against Staphylococcus aureus. Copper – dopped bioactive glass nanoparticles particles with ∼70 nm in size and relatively crystalline structure were synthesized. Porous nanocomposite scaffolds prepared with the copper – doped nanoparticles are cytocompatible, promoted the mineralization of bone-like apatite in simulated body fluid, and stimulated the osteogenic differentiation of stem cells as judged by an increased activity the enzyme alkaline phosphatase. The antibacterial activity exhibited by the nanocomposite scaffolds was not statistically superior to that of the neat polymer scaffold. Development of greater antibacterial activity in these nanocomposites would requires further research primarily related to the synthesis of more amorphous and soluble copper – dopped bioactive glass nanoparticles.

Fenites Naberezhne village (Kalmius river, Azov region)

In Eastern Azov (the village of Naberezhne, the left bank of the Kalmiusr river), the rocks, which mainly consists of minerals of the silica group (quartz, chalcedony), oxides and carbonates of Fe, Mn, Ca were found. They contain fluorite, as well as a small amount of acmite and ribeckite and an increased content of REE. These rocks are localized in the field of typical apogranitoid fenites, which are widely distributed in the Azov region. Oxide-carbonate-siliceous rocks are considered as the formation of the upper part of the fenitization column, where SiO2 was removed from fenitized granitoids and Fe, Mn, Ca, CO2, and REЕ, which are characteristic of carbonatites and related fenitizing fluids, were introduced. These oxide-carbonate-siliceous rocks, together with typical apogranitoid fenites, are the criteria for the search for carbonatites with apatite and rare earth mineralization.

Orthophosphate and alkaline phosphatase induced the formation of apatite with different multilayered structures and mineralization balance.

Mineralized collagen is a natural organic-inorganic composite. The combination of organic collagen and inorganic apatite to form different nanostructures is the key to producing bone substitutes with biomechanical properties that are as identical to normal bone as possible. However, the formation of apatite with different nanostructures during collagen mineralization is unexplored. Here, pyrophosphate (Pyro-P), as an important hydrolysate of adenosine triphosphate in the body, was introduced to prepare mineralized collagen under the regulation of alkaline phosphatase (ALP) and orthophosphate (Ortho-P). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results showed that mineralized collagen, which combined with different crystallinities and multilayered structured apatite, was successfully prepared. A combination of ion chromatography (IC), Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD), and thermogravimetry (TG) analyses revealed the crucial role of Ortho-P in the formation of multilayered flower-shaped apatite with different crystallinities and in the maintenance of mineralization balance. Mineralization balance is of great significance for maintaining normal bone morphology during bone regeneration. Overall, our results provide a promising method to produce new bone substitute materials for the repair of large bone defects and a deeper insight into the mechanisms of biomineralization.

A nanostructured look of collagen apatite porosity into human mineralized collagen fibril

Bone tissue is a hierarchical material characterized at nanoscale by the mineralized collagen fibril, a recurring structure mainly composed of apatite minerals, collagen and water. Bone nanostructure has a fundamental role in determining the mechanical behavior of the tissue and its mass transport properties. Diffusion phenomenon allows to maintain an adequate supply of metabolites in the mechanisms of bone remodeling, adaptation and repair. Several analytical and computational models have been developed to analyze and predict bone tissue behavior. However, the fine replication of the natural tissue still represents a challenge. Insights on the structural organization at nanoscale and on the influence of apatite mineral crystals on the diffusion coefficient lead to outline the functional conditions for the development of biomimetic strategies for bone tissue engineering. Thorough understanding of bone nanostructure is essential to improve longevity of bioscaffolds and to decrease the risk of failure by controlling their mechanical and biological performance.

Geology, Petrographic Characteristics and Tectonic Structure of Paleoproterozoic basement of Kabul Block (North Eastern Afghanistan), Initial Findings

The Paleoproterozoic basement of Kabul Block is a cratonic basement in north eastern Afghanistan. Precambrian Kabul Block including metamorphic rocks only takes place at the base of the study area. The Neo-Proterozoic Welayati formation overlies the Paleo-Proterozoic Sherdarwaza formation with a tectonic contact, and they both overlay Khair Khana formation. In the region, Alghoi meta granitoid intruded into both Khair Khana and Sherdarwaza formations. The Khair Khana formation contains of granulites, granitic gneisses ve amphibolites. The mineral assemblages of granulites are plagioclase + quartz + K-feldspar + orthopyroxene + clinopyroxene (diopside/augite). Granitic gneisses are observed as hornblende gneiss, garnet-biotite gneiss and pyroxene-gneiss. Hornblende-gneisses include hornblende + quartz + K-feldspar mineral assemblage, garnet-biotite gneisses are evident with plagioclase + quartz + K-feldspar + biotite (red) + garnet mineral assemblage, and pyroxene gneisses include quartz + plagioclase + biotite + clinopyroxene mineral assemblage. Amphibolites consist of hornblende + plagioclase + quartz ± zoisite ± sphene ± ilmenite ± apatite mineral assemblage. The Sherdarwaza formation contains marbles, amphibolites, biotite gneisses, micaschists and migmatites. Marbles consist of calcites ± quartz ± apatite. In amphibolites, harnblende + plagioclase + quartz ± epidote ± zoisite ± garnet mineral assemblage are observed. Biotite gneisses include plagioclase + quartz + microcline + biotite ± sphene ± apatite ± zircon mineral assemblage. Micachists consist of quartz + plagioclase + microcline + biotite ± sphene ± apatite mineral assemblage. Migmatites include plagioclase + quartz + microcline +biotite ± sphene ± apatite mineral assemblage. Alghoi meta granitoid is generally observed as stocks and small masses, and sometimes it shows foliation. It consists mainly of meta granites. The meta granites that show granular texture include plagioclase + quartz + K-feldspar + biotite + hornblende. The Welayeti formation contains quartzite, kyanite-garnet-staurolite schist, garnet-mica schist, kyanite-garnet-mica schist and garnet-muscovite schist. Quartzite include quartz ± muscovite ± biotite. They are observed hornblende + quartz + plagioclase ± garnet ± epidote ± zoisite ± rutile ± magnetite in amphibolites. Kyanite-garnet-staurolite schists are evident with staurolite + kyanite + garnet + mica + biotite + quartz + plagioclase ± apatite ± epidote ± ilmenite ± monazite mineral assemblage. Garnet-mica schists and kyanite-garnet-mica schists include quartz + plagioclase + biotite + muscovite + kyanite + garnet ± chlorite ± apatite ± tourmaline ± sphene ± rutile. In garnet-muscovite schists, muscovite + quartz + plagioclase + garnet ± tourmaline ± apatite ± zircon are observed. The granulites in Kabul Block are together with granite gneisses, and they can be separated under one formation. Granulites show different mineral compositions, Usually, they are without garnet, in some cases they include garnet. The amount of plagioclase is higher in them according to other rocks. In some cases, the composition of granulites is very similar to that of quartz mangarites that indicates high temperature and pressure of the metamorphism process and shows that this block is related to a segment of Columbia and Rodinia supercontinents during Paleoproterozoic collisional events.

An ab-initio study on the thermodynamics of disulfide, sulfide, and bisulfide incorporation into apatite and the development of a more comprehensive temperature, pressure, pH, and composition-dependent model for ionic substitution in minerals

AbstractThe mineral apatite, Ca10(PO4)6(F,OH,Cl)2, incorporates sulfur (S) during crystallization from S-bearing hydrothermal fluids and silicate melts. Our previous studies of natural and experimental apatite demonstrate that the oxidation state of S in apatite varies systematically as a function of oxygen fugacity (fO2). The S oxidation states –1 and –2 were quantitatively identified in apatite crystallized from reduced, S-bearing hydrothermal fluids and silicate melts by using sulfur K-edge X-ray absorption near-edge structure spectroscopy (S-XANES) where S 6+/ΣS in apatite increases from ~0 at FMQ-1 to ~1 at FMQ+2, where FMQ refers to the fayalite-magnetite-quartz fO2 buffer. In this study, we employ quantum-mechanical calculations to investigate the atomistic structure and energetics of S(-I) and S(-II) incorporated into apatite and elucidate incorporation mechanisms.One S(-I) species (disulfide, S22−) and two S(-II) species (bisulfide, HS−, and sulfide, S2−) are investigated as possible forms of reduced S species in apatite. In configuration models for the simulation, these reduced S species are positioned along the c-axis channel, originally occupied by the column anions F, Cl, and OH in the end-member apatites. In the lowest-energy configurations of S-incorporated apatite, disulfide prefers to be positioned halfway between the mirror planes at z = 1/4 and 3/4. In contrast, the energy-optimized bisulfide is located slightly away from the mirror planes by ~0.04 fractional units in the c direction. The energetic stability of these reduced S species as a function of position along the c-axis can be explained by the geometric and electrostatic constraints of the Ca and O planes that constitute the c-axis channel.The thermodynamics of incorporation of disulfide and bisulfide into apatite is evaluated by using solid-state reaction equations where the apatite host and a solid S-bearing source phase (pyrite and Na2S2(s) for disulfide; troilite and Na2S(s) for sulfide) are the reactants, and the S-incorporated apatite and an anion sink phase are the products. The Gibbs free energy (ΔG) is lower for incorporation with Na-bearing phases than with Fe-bearing phases, which is attributed to the higher energetic stability of the iron sulfide minerals as a source phase for S than the sodium sulfide phases. The thermodynamics of incorporation of reduced S is also evaluated by using reaction equations involving dissolved disulfide and sulfide species [HnS(aq)(2−n) and HnS(aq)(2−n); n = 0, 1, and 2] as a source phase. The ΔG of S-incorporation increases for fluorapatite and chlorapatite, and decreases for hydroxylapatite, as these species are protonated (i.e., as n changes from 0 to 2). These thermodynamic results demonstrate that the presence of reduced S in apatite is primarily controlled by the chemistry of magmatic and hydrothermal systems where apatite forms (e.g., an abundance of Fe; solution pH). Ultimately, our methodology developed for evaluating the thermodynamics of S incorporation in apatite as a function of temperature, pH, and composition is highly applicable to predicting the trace and volatile element incorporation in minerals in a variety of geological systems. In addition to solid-solid and solid-liquid equilibria treated here at different temperatures and pH, the methodology can be easily extended to different pressure conditions by just performing the quantum-mechanical calculations at elevated pressures.

Crystal-chemical and morphological interpretation of the biocompatibility of compounds in a Ca-Na-Bi-fluorapatite system.

This work is devoted to the study of the features of isomorphism in compounds of a Ca-Na-Bi-P-O-F system with a crystalline structure of the mineral apatite, as well as its effect on the biocompatibility of substances in relation to human cells in an in vitro model. A Ca10-2xBixNax(PO4)6F2 system (x = 0, 1, 2, 3, 4, and 5) is characterized by continuous isomorphism, which follows from the minimum deviations of the unit cell parameters from the Vegard and Rötgers rules. The refinement of the crystal structure showed that the cations are unevenly distributed between the 4f and 6h positions of the crystal structure of apatite: the bismuth ions are predominantly localized in the 6h position, while the sodium ions are concentrated in the 4f position. A standard MTT test of the biocompatibility of compounds with x = 1, 2, 3, and 4, and at x = 1 showed an anomaly in the form of an increased relative cell growth rate. This paper discusses the possible crystal-chemical and morphological reasons for this phenomenon.

A comprehensive overview on the origin of intrusive rocks and polymetallic mineralization in the Tongling ore-cluster region, lower Yangtze River Metallogenic Belt: Geological and geochemical constraints

The Tongling ore-cluster region is one of the most important Cu-Au polymetallic producers in the famous Lower Yangtze River Metallogenic Belt (LYRMB) in eastern China. The Cu-Au polymetallic ore deposits can be divided into four types, i.e., skarn, strata-bound hydrothermal, porphyry, and cryptobreccia, closely related to the Late Jurassic to Early Cretaceous magmatism. We summarize the geology of the Mesozoic Cu-Au deposits in Tongling, eastern China, and revisit the age distributions and geochemical characteristics of associated Mesozoic intrusions, by integrating a large number of published geochemical data (including major and trace elements for both early-stage and late-stage intrusions, whole-rock Sr-Nd-Pb isotopes, and zircon U-Pb age and Hf isotopes for early-stage intrusions), to reveal their sources and genesis.According to the U-Pb ages of intrusions, the main magmatic events in the area can be divided into two stages, i.e., 152–135 Ma and 135–124 Ma, respectively. The early-stage magmatism mainly produced Cu-Au mineralization-related dioritic intrusions, including pyroxene diorite-pyroxene monzodiorite, quartz diorite-quartz monzodiorite, and granodiorite, showing unobvious geochronological order. Geochemical data of Late Jurassic-Early Cretaceous intrusions from the early-stage magmatism suggest that they are all derived from a similar source composed of different proportions of slab-derived melt, metasomatized lithospheric mantle, and a lesser content of lower crust materials. Among them, the key differences lie in that more lower crust materials are incorporated in the source of intermediate-felsic rocks compared to intermediate-basic rocks. The late-stage magmatism produced a wide variety of rocks (diorite porphyry, syenite porphyry, granite porphyry, monzonite, and granite porphyry), which are related to Pb-Zn deposits. The late-stage igneous rocks may evolve from the early-stage rocks and have experienced fractional crystallization of apatite, ilmenite, and other minerals. Both early and late-stage magmatic events in the Tongling region were formed in the subduction setting, and corresponding to compression and extensional setting, respectively.Besides, the H-O isotopes of different kinds of minerals suggest that the ore-forming fluids of most ore deposits were mainly derived from the magma and mixed with a small amount of meteoric water in the late-stage mineralization. The S isotopes of sulfides show that the ore-forming materials come from the magma, accompanied by the addition of original sediments.

Health risk assessment of nitrate and fluoride toxicity in groundwater contamination in the semi-arid area of Medchal, South India

Hydrogeochemical controlling variables for the high rate of groundwater contamination in a shallow hard rock aquifer of the semi-arid region of Medchal District, Telangana State, South India, and its associated health risk to children and adults were studied in detail. A total of 56 groundwater samples were analysed for major ion chemistry in pre- and post-monsoon seasons in 2019 year. Spatial distribution, hydrochemical facies, water–rock interaction, health risk assessment, carcinogenic risk, and principal component analyses were carried out to assess the water quality. Spatial distribution of nitrate and fluoride concentrations, high values were observed in the northern, southern, central, and south-western parts of the region. In terms of NO3−, about 88% and 63% and for F− 45% and 32% of the groundwater samples are non-acceptable limits of nitrate 45 mg/l and fluoride 1.5 mg/l during pre- and post-monsoon seasons, respectively. Modified Gibb’s plot showed the majority of the area is dominated by rock dominance and evaporation mechanisms. Statistical analysis reveals that water chemistry is governed by weathering of feldspar minerals and the cation exchange reaction mechanism. The petro-graphical studies revealed the dominance of plagioclase, orthoclase, quartz, biotite, apatite, and hornblende minerals in the host rock. The factor analysis results reveal that the geogenic and anthropogenic activities contribute to groundwater chemistry. Health risk assessment was carried out by calculating the hazard quotient (HQ) on the basis of intake exposure of groundwater, as per the USEPA. Results were obtained for total hazard index value greater than 1 for adults and children, which causes non-cancerous health effects.

Magmatic origin and petrogenesis characterization of syenite rock from Pakkanadu alkaline complex, Southern Granulite Terrain, India: Implication on emplacement and petrogenetic history

The present study mainly focused on understanding the magmatic origin and petrogenesis characterization based on the Petrography, major, trace and Rare Earth Element (REE) signatures in the alkaline syenite from Pakkanadu alkaline carbonatite complex. The alkaline plutons from South Indian granulite terrain are intruded along with Archaean epidote-hornblende gneisses. The study area was carbonatite complexes of Tamil Nadu and is characterized by a group of rock associations Carbonatite-Syenite-Pyroxenite - Dunite. From Harker various patterns Pakkanadu alkaline complex syenite showed increasing trends of SiO2, Al2O3, Na2O + K2O opposite to decreasing order of CaO, Fe2O3, MgO, TiO2, P2O5 and MnO trend, suggest fractionation of clinopyroxene, hornblende, sphene, apatite and oxide minerals and feldspar that ruled the fractionation. The concentration of trace elements enriched in Large Ion lithophile elements (LILE) (Ba, Sr, and Rb) elements and High Field Strength Elements (HFSEs) indicated that the dyke intrusion by differentiation of magma from a mantle source. Rare earth element (REE) distribution of Light rare earth element (LREE) enriched and High rare earth element (HREE) depleted pattern show strongly fractionated pattern with moderate Eu anomalies. Plots of tectonic discrimination diagrams of Pakkanadu samples fall in the field of syn-COLG field to the VAG syn- COLG field. For the first time, this type of study was carried out in the study region in a detailed manner. The present study significantly exposed the petrography, petrogenesis and magmatic origin process in the Pakkanadu alkaline carbonatite complex.

Occurrence and mechanism of uranium enrichment with a unique eolian sedimental environment in the Pengyang uranium deposit, Ordos Basin

The Pengyang uranium deposit is a recently discovered large-scale uranium deposit in the Lower Cretaceous Luohe Formation in the southwestern Ordos Basin, China, and this high content of active uranium in the ore suggests that the Pengyang uranium deposit is generally suitable for in situ leaching mining. In this study, the uraniferous sandstones from the Luohe Formation were analyzed in detail. The mineral symbiosis and uranium occurrence state were studied using scanning electron microscopy, energy spectral analysis, backscattering detection, electron probe microanalysis, and sequential extraction procedures for uranium. Results show that the uranium minerals are mostly disseminated, clustered, or veinlet, being distributed along the edges and in the pores between detrital grains, and they are usually closely symbiotic with anatase, pyrite, apatite, and clay minerals. The uranium minerals are mainly pitchblende, with a small amount of coffinite. The results of sequential extraction procedures reveal that the uranium in uraniferous sandstones mainly exists in two occurrence forms of uranium minerals and adsorbed uranium and that the proportion of minerals is significantly higher than that of adsorbed uranium. The contents of carbonate-bound uranium and organic-pyrite-bound uranium in medium- and high-grade samples increased notably. The formation of the Pengyang uranium deposit is closely related to the participation of reducing fluids such as oil and gas. The types and symbiotic relationships of altered minerals in the deposit indicate that ore-bearing sandstones have experienced a variety of fluid activities. Numerous alteration minerals, including anatase, pyrite, apatite, and clay minerals, in the uraniferous sandstone have played various roles in the complex mineralization process of adsorption, catalysis, reduction, and precipitation. In-situ S isotope of the colloidal pyrite shows that the biological process is of great significance to the enrichment and precipitation of colloidal pyrite and uranium. These may be the important mechanisms of uranium precipitation and enrichment.