Major Minerals Research Articles

P11-020-23 Associations Between Major and Trace Minerals Intake and Bone Health in Postmenopausal Women With Osteopenia

P11-020-23 Associations Between Major and Trace Minerals Intake and Bone Health in Postmenopausal Women With Osteopenia

The genesis of metamorphosed Paleoproterozoic massive sulphide occurrences in central Colorado: geological, mineralogical and sulphur isotope constraints

AbstractPaleoproterozoic massive Cu-Zn±Pb±Au±Ag sulphide deposits metamorphosed to the middle-upper amphibolite facies in central-south Colorado formed in a volcanic arc setting on the edge of the Yavapai crustal province. Previously published U-Pb ages on spatially related granitoids range from ∼1.9 to ∼1.1 Ga, while Pb isotope studies on galena from massive sulphides suggest mineralization formed at around 1.8–1.7 Ga. Some deposits in the Dawson-Green Mountain trend (DGMT) and the Gunnison belt are composed of Cu-Zn-Au-(Pb-Ag) mineralization that were overprinted by later Au-(Ag-Cu-Bi-Se-Te) mineralization. Sulphide mineralization is spatially related to amphibolite and bimodal, mafic-felsic volcanic rocks (gabbro, amphibolite, rhyolite and dacite) and granitoids, but it occurs mostly in biotite-garnet-quartz±sillimanite±cordierite schists and gneisses, spatially related to nodular sillimanite rocks, and in some locations, exhalative rocks (iron formations, gahnite-rich rocks and quartz-garnetite). The major metallic minerals of the massive sulphides include chalcopyrite, sphalerite, pyrite, pyrrhotite, and magnetite, with minor galena and gahnite. Altered rocks intimately associated with mineralization primarily consist of various amphiboles (gedrite, tremolite and hornblende), gahnite, biotite, garnet, cordierite, carbonate and rare högbomite. The Zn/Cd ratios of sphalerite (44 to 307) in deposits in the DGMT fall within the range of global volcanogenic massive sulphide (VMS) deposits but overlap with sphalerite from sedimentary exhalative (Sedex) deposits. Sulphur isotope values of sulphides (δ34S = −3.3 to +6.5) suggest sulphur was largely derived from magmatic sources, and that variations in isotopic values resulting from thermochemical sulphate reduction are due to small differences in physicochemical conditions. The preferred genetic model is for the deposits to be bimodal-mafic (Gunnison) to mafic-siliciclastic VMS deposits (Cotopaxi, Cinderella-Bon Ton, DGMT).

Chemical analysis and filtration efficiency of ceramic point-of-use water filters

Ceramic water filters (CWFs) are globally employed as a point-of-use water treatment technology. Although, there are no standards to regulate the use of these CWFs in developing countries, they are gaining acceptability for domestic water treatment. This study sought to assess and compare the efficiency of commercially available types of CWFs and to propose a consumer selection guide for the purchase and use of CWFs. The CWFs selected for the study were, Ball filter with activated carbon (BF + AC), Candle filter (CF), and Pot filter (PFcs) coated with colloidal silver. The elemental and mineral oxide composition of the selected CWFs were analysed with x-ray fluorescence method. Furthermore, the raw unfiltered water (from three different common sources), and the filtrates obtained with the CWFs were analysed for their physicochemical, metal ion removability, and microbial correction. The x-ray fluorescence analysis indicated that Al2O3 and SiO2 were the major mineral oxide compositions of the selected CWFs. These metal oxides were present in varying concentrations. The CWFs showed turbidity reduction of 74.28–99.40%, Mn and Fe reduction of 54.04–98.48% and 48.82–97.50% respectively. In addition, the total coliform reduction by the selected CWFs ranged from 2.31 to 76.97%. It was therefore observed from the results that, the efficiency of commercially available CWFs varied in the order BF + AC > CF > PFcs. BF + AC was the most efficient in both physicochemical and microbial correction of all water sources. CWF selection guide for consumers based on different sources of water which considered the physicochemical parameters, biological parameters and Water Quality Index was discussed. This has an implication for regulation and standardization of CWFs.

Proximate, Mineral and Sensory Analysis of Maize-Soybeans Composite Flour Biscuit Enriched With Edible Insect “Kanni”

Maize was fortified with soybeans flour and was enriched with edible insect “kanni”. Maize, soybeans and “kanni” were extracted and processed into raw dried flour. Appropriate quantities of maize, soybeans flour and “kanni” (on dry weight basis) were measured and mixed at different concentrations while 100% maize flour as control. Proximate, mineral and sensory analysis of biscuits made from the flour was determined. The proximate, mineral and sensory properties of maize-soybeans composite flour biscuit samples (A, B and C) were evaluated. The biscuits contained moisture (10.42-11.02%), protein (11.85-15.95%), ash (1.75-2.11%), fat (16.18-17.26%), fibre (2.52-4.36%) and carbohydrate content (49.95-56.00%), respectively. Major mineral contents in the biscuits were sodium, iron, zinc, potassium, magnesium and calcium of 40.95-73.25, 1.75-2.45, 1.22-1.53, 50.76-87.45, 8.15- 11.22 and 78.75-108.56mg/100ml, respectively. However, sample C (15% SB and 15% K) had the highest value of fibre, protein and carbohydrate content as well as highest mineral value of sodium, magnesium and iron. However, overall acceptability of sample C was significantly higher than others. This study reveals that the flour blend can be use for production of biscuits and can be a substitute for wheat flour in pastries.

Effect of nongenetic factors on milk compositional aspects and bacteriological quality in Tunisian Maghrebi dromedaries (Camelus dromedarius) reared under a traditional pastoral management system

This study was planned to evaluate the impact of nongenetic factors on physicochemical composition and microbial quality of milk from Maghrebi camels kept under traditional system in oasis areas of Tunisia. Milksamples from 69 animals were collected from lactating Negga over winter and summer. Animals belonging to private flocks were between 5 and 17.5 years of age, with parity numbers ranging from first to sixth. Samples were analyzed for basic composition and microbiological features according to standard methods. No significant association (P > 0.05) between physical characteristics and nongenetic factors has been observed. The maximum contents of total solids, protein, casein, and fat content were observed during winter. The third lactation was characterized with the highest content of total solids, protein, casein, and lactose; while the highest fat content was recorded in the second lactation. The highest levels of Ca, P, and K were recorded in the winter (P<0.01) whereas Na showed an opposite pattern (P<0.01). All major minerals were higher in milk from multiparous than primiparous camels, with maximum concentrations at the fourth lactation. The uppermost levels of mineral concentrations and chemical constituent were recorded in the age class of 7≤ age ≤ 9 years. The microbial analysis of raw milk which is affected by season, parity, and age showed higher overall contamination levels in all studied bacterial counts. The highest levels were observed in winter, among the multiparous and oldest Negga. The results highlighted the complete absence of the two dangerous pathogens Salmonella and CSR in all analyzed samples.

Interpretation of Hyperspectral Shortwave Infrared Core Scanning Data Using SEM-Based Automated Mineralogy: A Machine Learning Approach

Understanding the mineralogy and geochemistry of the subsurface is key when assessing and exploring for mineral deposits. To achieve this goal, rapid acquisition and accurate interpretation of drill core data are essential. Hyperspectral shortwave infrared imaging is a rapid and non-destructive analytical method widely used in the minerals industry to map minerals with diagnostic features in core samples. In this paper, we present an automated method to interpret hyperspectral shortwave infrared data on drill core to decipher major felsic rock-forming minerals using supervised machine learning techniques for processing, masking, and extracting mineralogical and textural information. This study utilizes a co-registered training dataset that integrates hyperspectral data with quantitative scanning electron microscopy data instead of spectrum matching using a spectral library. Our methodology overcomes previous limitations in hyperspectral data interpretation for the full mineralogy (i.e., quartz and feldspar) caused by the need to identify spectral features of minerals; in particular, it detects the presence of minerals that are considered invisible in traditional shortwave infrared hyperspectral analysis.

Effects of Glucosinolate-Enriched Red Radish (Raphanus sativus) on In Vitro Models of Intestinal Microbiota and Metabolic Syndrome-Related Functionalities.

The gut microbiota profile is determined by diet composition, and therefore this interaction is crucial for promoting specific bacterial growth and enhancing the health status. Red radish (Raphanus sativusL.) contains several secondary plant metabolites that can exert a protective effect on human health. Recent studies have shown that radish leaves have a higher content of major nutrients, minerals, and fiber than roots, and they have garnered attention as a healthy food or supplement. Therefore, the consumption of the whole plant should be considered, as its nutritional value may be of greater interest. The aim of this work is to evaluate the effects of glucosinolate (GSL)-enriched radish with elicitors on the intestinal microbiota and metabolic syndrome-related functionalities by using an in vitro dynamic gastrointestinal system and several cellular models developed to study the GSL impact on different health indicators such as blood pressure, cholesterol metabolism, insulin resistance, adipogenesis, and reactive oxygen species (ROS). The treatment with red radish had an influence on short-chain fatty acids (SCFA) production, especially on acetic and propionic acid and many butyrate-producing bacteria, suggesting that consumption of the entire red radish plant (leaves and roots) could modify the human gut microbiota profile toward a healthier one. The evaluation of the metabolic syndrome-related functionalities showed a significant decrease in the gene expression of endothelin, interleukin IL-6, and cholesterol transporter-associated biomarkers (ABCA1 and ABCG5), suggesting an improvement of three risk factors associated with metabolic syndrome. The results support the idea that the use of elicitors on red radish crops and its further consumption (the entire plant) may contribute to improving the general health status and gut microbiota profile.

RELATIONSHIP BETWEEN TOBERMORITE AND CARBONATION IN LIGHTWEIGHT AERATED CONCRETE (AAC) BY RIETVELD ANALYSIS

Carbonation of lightweight aerated concrete (AAC) is a reaction in which Tobermorite, a major mineral, decomposes into calcium carbonate and silica gel, causing cracks in the AAC. It is important to understand the progress of carbonation in order to determine the maintenance and replacement time of AAC. In this study, Rietveld analysis was applied to AAC to quantify the major minerals including Tobermorite and to clarify the changes in the content of Tobermorite and calcium carbonate due to carbonation.

Geochemical and mineralogical evaluation of Libale iron- rich manganese deposit, North-central Nigeria

The iron-rich manganese deposits of Libale area is located within the basement complex of North-central Nigeria. Mineralogically, the major mineral phases are: goethite (Fe2O3.H2O), spessartine (Mn32+Al2(SiO4)3), hematite (Fe2O3), and quartz (SiO2), while minor mineral phases are orthoclase (Al2O3.K2O.6 SiO2), illite (KAl2Si3AlO10(OH)2), and manganite (Mn2O3.H2O) suggesting a trend of mineral assemblage attributed to the differential mineralization of the iron-manganese deposit that may have been caused by the geochemical tectonic activity during its formation. Geochemically, on average, the Fe2O3, SiO2, Al2O3, CaO, P2O5 content are 34.59 wt.%; 26.30 wt.%; 6.94 wt%, 2.60 wt%, 2.01 wt% correspondently while K2O and TiO2 are less than 1wt%. Suggesting oxide facies type for the deposit. The trace element composition of V (1040 ppm), Cr (100 ppm), Co (833.33 ppm), Cu (1740 ppm), Nb (1280 ppm), W (240 ppm), Ta (320 ppm) and Zr (302 ppm) were relatively high compared to Maro, Muro and Kakun BIFs in North-central Nigeria. Bivariate plot of Fe2O3 Vs. Al2O3, suggest enrichment of Fe2O3 but depleted in SiO2 and Al2O3, which possibly indicates replacement of precursor silica and kaolinite with goethite which are subsequently dehydrated to hematite. Al2O3-SiO2-Fe2O3 ternary diagram indicates Precambrian Banded Iron Formation (BIF) for the Libale iron- rich manganese deposits, this was confirmed by MnO Vs. FeO. Discriminative plots: FeO. SiO2 - (FeO + MnO) - Fe2O3 and Al2O3+ K2O + Na2O Vs. MnO + FeO confirmed mixed facies as the analyzed data plots between silicate facies and magnetic-silicate facies, this is linked to chemical association between Al2O3 and SiO2 for the iron-rich as it confirms a transitional grade of silicate facies to magnetite-silicate facies. SiO2 Vs. Al2O3 plot revealed hydrothermal and diagenetic processes for its deposition. The iron-rich manganese deposit is of low grade iron (Av. Fe=24.19%) characterized by ferruginous manganese (Av. MnO2=23.82%) based on the generalized percentages of element of major interest in assessing quality of iron and manganese ore, therefore, good for cast iron production.

Study of Palaeoclimate Reconstruction Using Sediments and Micropaleontology in the Karankadu Estuary, Ramanathapuram District, Tamil Nadu, India

The study of sedimentary characteristics and paleontology is very useful in assessing the past environment of a study area. The Karankadu estuary study area is considered to be one of the most ecologically diverse in the Ramanathapuram district of southern India. The sedimentological and recent foraminiferal assemblages were studied using a drill core from the estuary. Foraminifera analyses, grain size analyses, heavy mineral analyses and XRD maps were prepared for the present study. A total of 30 species were identified from the following suborders: Rotalina, Lagenina, Mollusca, Miliolina, and Textularina. Grain size analysis identified the substrate as mostly silty clay. Heavy mineral analysis identified 90% of light minerals and 10% of heavy minerals. In XRD analysis, quartz and feldspar appeared as major minerals and garnet, zircon, hypersthene, magnetite and ilmenite as minor minerals. The present study shows that the environment is more diverse due to its quiet character and less responsive to hazardous events such as floods and waves.

Osteogenic Potential of Nano-Hydroxyapatite and Strontium-Substituted Nano-Hydroxyapatite.

Nanohydroxyapatite (nanoHA) is the major mineral component of bone. It is highly biocompatible, osteoconductive, and forms strong bonds with native bone, making it an excellent material for bone regeneration. However, enhanced mechanical properties and biological activity for nanoHA can be achieved through enrichment with strontium ions. Here, nanoHA and nanoHA with a substitution degree of 50 and 100% of calcium with strontium ions (Sr-nanoHA_50 and Sr-nanoHA_100, respectively) were produced via wet chemical precipitation using calcium, strontium, and phosphorous salts as starting materials. The materials were evaluated for their cytotoxicity and osteogenic potential in direct contact with MC3T3-E1 pre-osteoblastic cells. All three nanoHA-based materials were cytocompatible, featured needle-shaped nanocrystals, and had enhanced osteogenic activity in vitro. The Sr-nanoHA_100 indicated a significant increase in the alkaline phosphatase activity at day 14 compared to the control. All three compositions revealed significantly higher calcium and collagen production up to 21 days in culture compared to the control. Gene expression analysis exhibited, for all three nanoHA compositions, a significant upregulation of osteonectin and osteocalcin on day 14 and of osteopontin on day 7 compared to the control. The highest osteocalcin levels were found for both Sr-substituted compounds on day 14. These results demonstrate the great osteoinductive potential of the produced compounds, which can be exploited to treat bone disease.

Influence of geochemistry and topography on vegetation in tropical Nigeria: Geochemistry and soil thickness surpass topographic position

The influence of lithospheric parameters on vegetation varies from one location to another, regardless of the prevailing climatic conditions. Reliable scientific information on the vegetation-environment relationship is crucial to sustainable agriculture and natural resource management. Poignantly, such information is not readily available, particularly in resource-poor countries. In this study, we assemble spatially referenced datasets on vegetation pattern, topography, soil thickness and bedrock geochemistry. We subject the datasets to global and local spatial regression analyses on GeoDa 1.18 and MGWR 2.2.1 platforms. Our intention is to examine the influence of lithospheric parameters on vegetation patterns over a climatically homogenous basin in the rainforest belt, southwestern Nigeria. The results of our study show that the variation in vegetation pattern can be explained by soil thickness, topographic curvature, and bedrock concentrations of major minerals. Bedrocks’ KO2/Fe2O3 enrichment and soil thickness are the main lithospheric parameters that influence vegetation pattern in the study area. Bedrocks’ K enrichment is relatively high and less heterogeneous while P enrichment is very low and highly heterogeneous across the study area. Fe concentration is highly heterogeneous, with the highest enrichment recorded for schist and the lowest for gneiss. While the concentration of K is discriminately high in granitic rocks, the highest concentration of P is recorded for schist. Vegetation index is averagely higher on schist than on granitic rocks. Regression models show that bedrock geochemistry and soil thickness exert the greater influence on vegetation in the study area. Based on the available data, we observe that the study area’s greenery can self-rejuvenate if left undisturbed. Our data show that the study area could support a large pool of forest carbon stocking. This potential makes the study area suitable for the UN REDD + program in Nigeria.

Diffusion of radioisotopes in Fe-montmorillonite relevant to geological disposal of HLW

Bentonite clay is proposed as backfill or buffer materials in the engineered barrier system for high-level nuclear waste (HLW) disposal in a deep geological repository (DGR). The major clay mineral of bentonite, montmorillonite (Mt), is expected to undergo alteration owing to its interaction with corrosion products from overpack/canister over a long period of time. As a typical and simple altered clay mineral, we used Fe(II)−Mt and Fe(III)−Mt for preliminary investigation on the diffusion behavior of various radioisotopes relevant to HLW. Instantaneous planar source method was used to determine the apparent diffusion coefficient (Da) using compacted (ρd = 1.6 g/cm3) and water saturated Fe−Mt. In Fe(III)−Mt, the Da values in m2/s for 137Cs+ = (3.9 ± 0.2) × 10−12, 133Ba2+ = (1.1 ± 0.6) × 10−12, 152+154Eu3+ = (2.2 ± 0.5) × 10−12 and 131I− = (5.5 ± 0.1) × 10−12. In Fe(II)−Mt, the Da values in m2/s for 22Na+ = (2.0 ± 1.2) × 10−11, 137Cs+ = (3.0 ± 0.4) × 10−12, 133Ba2+ = (1.4 ± 0.4) × 10−11, 152+154Eu3+ = (4.0 ± 0.7) × 10−12 and 131I− = (4.8 ± 1.0) × 10−12. In general, similar Da values are obtained for Fe(II)−Mt and Fe(III)−Mt. This is the first extensive study to report the diffusion behavior of radioisotopes in Fe−Mt.

Sediment flux and early diagenesis inferred from high-resolution XRF-CS data and iron and arsenic sulfides during the last 30 kyr in Lake Urmia, Iran: Implications for studies of hypersaline lakes

We analyzed by high resolution X-ray fluorescence core scanning (XRF-CS) the elemental composition of a 12.5 m long composite sediment core extracted from the hypersaline Lake Urmia (NW Iran). The main objective of the study was to reconstruct on a high temporal scale, the changes in sediment origin/inflow and water levels of Lake Urmia over the last 30,000 years. Combined with previously obtained results on 14C accelerated mass spectrometry (AMS) chronology, grain size and distribution of major minerals, albeit with a much lower temporal resolution than the XRF-CS data, this multi-proxy approach allowed recognition of specific hydrological changes and associated sedimentary processes in the Lake Urmia basin, including physical and chemical weathering, depositional fluxes and carbonate crystallization processes in lake water, and early diagenesis in anoxic bottom sediments. The high natural logarithm ratios (ln-ratios) of K/Ti, Ca/Ti and Sr/Ca, and low ln-ratios of Rb/Sr reveal increasing chemical weathering in the catchment area in conjunction with increasing authigenic carbonate precipitation in the lake. These findings reflect wet conditions, high lake levels and less saline water during the following intervals (i) 29.8–20.2, (ii) 15.2–13.3, (iii) 11.8–5.6 and (iv) 4.1–2.3 cal kBP. In contrast, the increasing ln-ratios of Rb/Sr associated with decreasing ln-ratios of K/Ti, Ca/Ti and Sr/Ca indicates enhanced erosion in the catchment area linked to drier conditions, lower lake levels and more saline conditions predominating at around 30–29.8 cal kBP, 20.2–15.2, 13.3–11.8, and 5.6–4.1 cal kBP. Based on the As-XRF-CS pattern and magnetic parameters we identified iron and naturally-occurring arsenic sulfides rarely reported from saline lakes, acting as specific indicators of anoxic conditions in the lake bottom environment. Moreover, XRF-CS data revealed short-lived periods with increasing chemical weathering in the catchment area at (i) 28.6–28.3, (ii) 27.3–27.1, (iii) 4.1–3.6 and (iv) 3.4–3.3 cal kBP, as well as increasing erosion at (i) 27.0–26.8, (ii) 26.3–26.0, (iii) 25.6–25.3 and (iv) 24.6–24.4 cal kBP. Overall, this study confirms the previously reported findings concerning the sediments of Lake Urmia as well as completing these, both by providing more details on the environment for the periods already identified and by highlighting events of short duration. In particular, the results reported here permit better definition of the processes of chemical weathering versus erosion in the catchment area, and of the oxygenation levels of the lake bottom. The close correlation of these long- and short-term changes with the North Atlantic climate system clearly indicates that the Lake Urmia area has been affected mainly by this system during the last 30 cal kBP.Over and above their value with regard to Lake Urmia, these new data fill an important gap in eastern Mediterranean/western Asia paleoclimate records as a whole, providing unique and continuous 30 cal kBP information on the possible driving mechanisms of the observed changes. These can be compared to existing data on paleoenvironmental and climatic changes on regional and global scales and can also be used in global circulation models.

Raman spectroscopy, assisted by X‐ray fluorescence and laser‐induced breakdown spectroscopy, to characterise original and altered mineral phases in the NWA 2975 Martian shergottite

AbstractA fragment of the NWA 2975 Martian meteorite, an enriched basaltic shergottite, was analysed to complete its geochemical characterisation performed 10 years ago. By this means, the feasibility of the employed techniques in a combined way for present and future space exploration missions can be tested. For this aim, Raman spectroscopy was used supported by micro energy dispersive X‐ray fluorescence (μ‐EDXRF) and laser‐induced breakdown spectroscopy (LIBS) for an accurate interpretation of molecular and elemental results. Raman spectroscopy results from two setups, InVia from Renishaw and RLS Simulator, were compared. The major minerals detected by Raman spectroscopy were pyroxenes (mainly augite, pigeonite and enstatite) and plagioclases (mainly shocked maskelynite). Raman spectroscopy allowed defining different metal compositions for these main minerals based on the secondary Raman spectroscopy bands in the 200–500 cm−1 region. In addition, other minerals were found such as merrillite, as well as pyrrhotite and apatite, in several veins and cracks of the meteorite, in agreement with the initial report by the Meteoritical Bulletin. Moreover, it should be highlighted that coesite was found for the very first time in this meteorite.

Textural and Chemical Characters of Lean Grade Placer Monazite of Bramhagiri Coast, Odisha, India

The present study aims to investigate the textural, mineralogical and geochemical characteristics of lean grade placer monazite from the Bramhagiri beach sand deposit to assess the possibility for its use in industrial applications. The bulk back dune sand deposit with 18 samples showed the elements uranium and thorium in traces, phosphorus and calcium in minor amounts, and alumina, silica and titanium in major amounts. Since apatite was absent in this placer deposit, P and Ca were attributed to monazite only. Based on the chemical analysis, it was established that the monazite mineral exists in this deposit. The monazite is generally below the −150- to +90-micron size range, and the concentration of the monazite mineral in the bulk back dune sand is around 0.01% by weight. The structural data and complete chemical analysis established that the monazite is Ce-monazite. The monazites with other heavy mineral sands of the Bramhagiri beach placer deposits were derived from the Eastern Ghats, which closely resembles the mineralogical composition of khondalite, charnockite, leptynite and pegmatite groups of rocks. The Eastern Ghats’ provenance appears to be the primary source for the heavy mineral assemblages of the Bramhagiri placer deposit. Thus, these monazite sands are derived from the granulite facies of metamorphic rocks such as khondalites and charnockites from the Eastern Ghats group of rocks. Garnet is the major mineral, following ilmenite and sillimanite. Zircon, rutile and monazite are minor minerals in the deposit. All these minerals are well liberated and have uniform shapes with variable densities and size ranges, with different magnetic, electrical and surface properties. Hence, the occurrences of these heavy minerals are of economic importance. Further, these minerals can be recovered individually for industrial applications.

Radiation-induced alteration of sandstone concrete aggregate

This study investigates the alteration of felsic sandstone-type rock, which is used as a coarse aggregate in concrete, subject to the effects of gamma-ray and neutron irradiation. The effects of three gamma-ray doses (27, 55, and 108 MGy) and four neutron fluence levels (1.22, 2.19, 6.99, and 14.30 × 1019 n/cm2, E ≥ 0.01 MeV) were investigated. Quartz and albite were found to be the major rock-forming minerals, with microcline intermediates, chlorite, and muscovite as the minors. Gamma rays caused no significant changes to the physical properties of the sandstone aggregates, even at high doses (108 MGy). In contrast, neutron irradiation caused alterations that became more pronounced at higher neutron fluences. The solid was confirmed to expand through metamictization of the rock-forming minerals. Quartz and muscovite were the most affected phases, whereas albite and microcline intermediates were only slightly affected, and chlorite was almost unaffected. The decrease in density was measured by He and water pycnometry, and this value was almost reproduced by calculations using the rock-forming mineral composition of the pristine sample measured using X-ray powder diffraction/Rietveld analysis and the cell volume change of the major forming minerals. In addition, light optical microscopy and scanning electron microscopy images confirmed the presence of intergranular and intragranular cracks. Intergranular cracks appeared to have initiated from the quartz grains, which expanded significantly. The intragranular cracks were frequently observed in the albite and microcline intermediates. These cracks can be described as radial cracks starting from the expanding quartz, caused by enforced displacement for deformation consistency with quartz expansion. The crack area ratio quantified by SEM image analysis corresponds to the discrepancy of the volume expansion difference calculated by He or water pycnometry and dimensional change measurements. An evaluation of solid expansion and crack openings in aggregates is important to estimate concrete degradation.

Lattice-preferred orientation (LPO) of olivine and amphibole in amphibole peridotites and neighboring hornblendites from Gapyeong, South Korea and implications for seismic anisotropy

Amphibole peridotites and neighboring hornblendites are often found in subduction zones. To understand the effect of amphibole-rich rocks on seismic anisotropy in subduction zones, we studied the lattice-preferred orientation (LPO) of olivine and amphibole in amphibole peridotites and neighboring hornblendites in Gapyeong, South Korea. The major minerals of amphibole peridotites were olivine (31–51% in volume), amphibole (28–47%), and orthopyroxene (7–16%). Amphibole in amphibole peridotites showed relatively high SiO2 and low TiO2 and Na2O contents (S-type amphibole), indicating that it was formed under supra-subduction conditions. Amphibole in amphibole peridotites showed the type-I, type-II, and type-IV LPO, whereas amphibole in neighboring hornblendites showed the type-III and type-IV LPO. In the case of olivine, most samples showed a mixture of A- and B-type LPO, and one sample showed a mixture of B- and C-type LPO. Many serpentine inclusions were found in olivines. Fourier-transform infrared (FTIR) analysis of the samples showed that the olivines contained a large amount of water (∼29000–45000 ppm H/Si). We also found many dislocations in olivines. These observations indicate that samples showing a mixture of A- and B-type LPO and a mixture of B- and C-type LPO of olivine were deformed under water-rich conditions by dislocation creep. In amphibole peridotites, the P-wave anisotropy of olivine was relatively low (0.9–4.8%), whereas the P-wave anisotropy of amphibole was high (6.5–17.7%). The maximum S-wave anisotropy of olivine was also relatively low (0.87–2.89%), whereas the maximum S-wave anisotropy of amphibole was high (3.81–15.19%). In hornblendites, the P-wave anisotropy and maximum S-wave anisotropy of amphibole were high (6.9–13.6% and 4.27–10.61%, respectively). The P-wave anisotropy and maximum S-wave anisotropy of the amphibole peridotites were in the range of 2.6–8.4% and 1.73–7.30%, respectively. The seismic velocity and anisotropy pattern of amphibole peridotites were more similar to those of amphibole than those of olivine, indicating that the seismic properties of amphibole peridotites were more strongly affected by amphibole than by olivine. Furthermore, the seismic anisotropy of the mixture of amphibole peridotite and hornblendite in subduction zones was also found to be significantly affected by the amphibole LPO in hornblendite.

Paleozoic VMS-type stratiform mineralization overprinted by Mesozoic vein-type mineralization in the Yushui copper deposit, eastern Guangdong, South China

The South China hosts a number of stratiform deposit in Late Paleozoic depression, including the Yushui copper deposit (which has a Cu grade up to 53% with an average grade of about 3.5%) in the Yong-Mei-Hui depression. The genesis type of Yushui copper ore is highly controversial due to the influence of post mineralization tectonic and magmatic activities, which affects the exploration of the deposits. Yushui copper deposit is mainly composed of stratiform ore body and stockwork orebody in the footwall, with typical VMS-type deposit characteristics and its mineralization age of 308 Ma. Small amounts of vein-type ore body can also be seen in the hanging wall dolomite of the stratiform ore body, which mainly develops along the joints and faults, and the mineral assemblage includes chalcopyrite, bornite, galena, sphalerite, tetrahedrite, furutobeite, and rare earth minerals (xenotime and bastnaesite). Hydrothermal sericite is also developed when vein-type ore body cut the sandstone in the footwall of stratiform ore body. Pristine euhedral xenotime and bastnaesite crystals from the Yushui Cu mineralized of veins ore body yield LA-ICP-MS weighted mean 206Pb/238U ages of 162.5 ± 6.7 Ma (1 s, MSWD = 11.8) and 164.6 ± 5.3 Ma (1 s, MSWD = 9.5), respectively. Hydrothermal sericite yields a plateau 40Ar–39Ar age of 163.19 ± 7.60 Ma, which is consistent with the xenotime and bastnaesite U–Pb age, suggesting that the vein-type Cu mineralized is generically related to the Middle-Late Jurassic hydrothermal event. These ages indicate that in addition to the major Late Paleozoic mineralization events that formed VMS-type stratiform ore body, there were also small-scale hydrothermal vein-type ore body formed during the Middle and Late Jurassic mineralization events that did not cause major disruptions to the earlier stratiform ore body. Combining with the chronological research of other copper deposits in the southeastern coastal area of China, this article believes that these 170 ∼ 155 Ma deposits were all due to the crust-mantle interaction caused by changes in the subduction angle of the ancient Pacific plate. Our study suggests that the southeastern margin of the South China has potential for the exploration of polymetallic hydrothermal mineralization related to Middle-Late Jurassic magmatic rock.

Research on price transmission in Chinese mining stock market: Based on industry

The strong impact of COVID-19 on the global mining market has caused severe fluctuations in the prices of mineral products and mining stocks. Meanwhile, geopolitical conflicts have exacerbated risks in minerals trade and mining stock transactions. In the face of uncertainties in the international economic landscape and volatility of stock prices, China, as the world's major mineral trading country, has become increasingly linked between its stock market and the mining economy. To clarify the characteristics of mining stock price fluctuations and the evolution of the transmission relationships, and identify the key nodes and main paths of price transmission, we select 100 Chinese mining stocks from January 2019 to October 2022, distinguish them according to the industry category, and use Granger causality test, minimum spanning tree model and complex network analysis method to study. The results show that: (1) Chinese mining stock prices have risen significantly since 2020, and there has been a “decoupling” phenomenon within the stock market, that is, the linkage between some mining stocks has weakened. (2) The stock price fluctuation characteristics and transmission effects of different mining industries are obviously different. Precious metal minerals (PM) have the most dramatic changes in price fluctuations, the most prominent hedging characteristics, and the rapid price response ability, which is the first to accept price transmission. rare earth and rare metal minerals (RE) are sensitive to price fluctuations and are usually the “leader” of the transmission path. Bulk non-ferrous minerals (BNFM) have the most stable price fluctuations and are closely related to other stocks, which is a “transit warehouse” in the transmission path. (3) The price transmission mechanism of Chinese mining stock market has gradually stabilized, and the main transmission paths of “Coal→Agricultural minerals (Agri)→BNFM→Steel” and “PM, Core minerals for new energy (NEM), and RE→BNFM” have been formed in 2022.