Major Minerals Research Articles

Mineralogy, geochemistry, and 40Ar/39Ar dating of hornblendite/amphibolite pods in Penjween Ophiolite of northeastern Iraq: Implications for petrogenesis and tectonics

Penjween ophiolite is one of the ophiolitic complexes of northeastern Iraq. The serpentinites within the Penjween Ophiolite hosts many pods of hornblendite and amphibolite, and dikes of diorite among many other igneous bodies. These pods have very sharp contacts with the surrounding mantle serpentinized harzburgites. The hornblendites and amphibolites are usually intimately intergrown together as extremely hard, dark green to black colored, fine-to medium-grained pods with ∼2 x ∼2 x ∼(0.5–1) m dimensions. This study presents petrography, mineral chemistry, whole-rock major and trace element geochemistry, and electron probe microanalyses (EPMA) for the major minerals in the studied rocks. The hornblendite is composed entirely of amphiboles (>99% vol.), meanwhile the amphibolite consists of comparable amounts of amphibole and plagioclase which occasionally occurs as layered rocks with banded texture. The diorite dikes are white in color and consist dominantly of coarse-grained plagioclase and less amphiboles. The amphiboles of these rocks belong to pargasite (Mg# 0.69–0.77) ─ edenite (Mg# 0.74–0.79) endmembers where pargasite is by far the predominant mineral; meanwhile the plagioclase is albite (Ab93.4An6.4Or0.2). The amphiboles are replacement products of pyroxenes indicated from the relict pyroxene within their crystals. The amphiboles are abnormally rich in various dust-like inclusions of transparent minerals like REE-rich epidote, rutile, zircon, apatite, titanite, and ore minerals like ilmenite, and pyrrhotite, oriented along the crystallographic axes and form distinct zones in the core of amphibole crystals. The geochemical characteristics of the studied hornblendite (MgO = 13.07%, Ni = 260 ppm, Mg# = 66.57) as well as the high Sc (33 ppm) and V (254 ppm) concentrations are collectively consistent with a mantle-derived, igneous origin. The primitive-mantle normalized trace elements spidergram showed enrichment (hump) in Ba, Th, U, La, Ce, Pb, and Sr, and depletion (trough) in Nb, Ta, K, and Ti. The chondrite-normalized REE diagram showed enrichment of LREE relative to HREE, indicated from the smooth and steady decrease in the negative slope from LREE towards HREE with a negligible Eu-anomaly. Various tectonic discriminating diagrams showed that the studied hornblendite, amphibolite pods and diorite dikes are of igneous fore-arc origin, formed from calc-alkaline and/or tholeiitic magma within an active continental margin setting. The 40Ar/39Ar laser age of hornblendite is late Paleocene (Thanetian) (57.8 ± 5.1 Ma) which might represent an event during the obduction between the oceanic fore-arc Island and the Arabian Plate during the Late Cretaceous/Paleocene period.

Interpretation of run-of-mine comminution and recovery parameters using multi-element geochemical data clustering

Multi-element (ME) datasets provide comprehensive geochemical signatures of an orebody and are commonly used to gain insight into the mineralogy, lithology, alteration patterns and to identify target-pathfinders. However, little effort is made in using these data to explain comminution or recovery characteristics. This paper describes an agglomerative hierarchical clustering approach applied to ME data from the Tropicana Gold Mine, Australia, and investigates the relationship between the resultant classes and run-of-mine comminution and recovery parameters. First, it is demonstrated how an industry scale ME dataset is prepared for clustering. The preparation consists of verifying the absence of interlaboratory and intralaboratory bias between measurements, centred log-ratio transformation (clr), normalisation and principal component analysis (PCA). Afterwards, the first case study indicate that the clustering separation is primarily driven by geochemical differences caused by major rock-forming mineral signatures (felsic vs mafic, alteration vs no alteration, chert or quartz lithologies, unmineralised vs mineralised material). This case study separates the ME dataset into five unmineralised and two Au-mineralised material classes. The second case study continues with the two identified mineralised material classes and further separates these samples into five new classes. These classes are explored geochemically and by using the spatial context (within domains) better matched with metallurgical test results. It is found that domain-related material class proportions assist in interpreting different processing proxies such as the Equotip hardness (Leeb), Bond Work index (BWi), Axb, and processing recovery and reagent consumption. Knowledge of the processing parameters per domain and class composition can be used to infer such characteristics in the absence of standard metallurgical tests. This new approach of gaining insights into comminution and recovery parameters through geochemical analysis demonstrates the benefit of the conceptualised material fingerprinting concept.

Reactive harzburgite and ultimate dunite formation as a result of boninite-like melt interaction: Petrological evidence from the Kırdağ ophiolite (Erzurum, NE Turkey)

In this study, the harzburgite-dunite suite in the mantle section of the Kırdağ ophiolite outcropping in the east of the Eastern Pontides (Erzurum, North-eastern Turkey) was examined in textural, mineral and whole-rock geochemical terms to interpret the mantle processes. Besides textural occurrences such as inclusions and exsolution lamellae, mineral and whole-rock geochemical properties provided clear evidence of melting and melt-peridotite interaction processes during harzburgite-dunite generation. The Fo-numbers of olivines and the Cr-numbers of spinels generally increased from the harzburgites to the dunites. In addition, the clinopyroxenes found only in the reactive harzburgite (Cr-number; up to 0.61) displayed depleted characteristics indicated high-degree partial melting and melt-rock interaction processes. The Cr-number, Mg-number, Fe3+-number, Al2O3 and TiO2 contents of the chromian spinels suggest that the harzburgite-dunite suite originated from depleted mantle with high-degree partial melting. The Fe3+ cation values of the chromian spinels were significantly higher in the dunites, suggests the alteration effects in oxidizing conditions. Also, the positive correlation between the Cr-numbers and TiO2 contents of the chromian spinels observed in the dunites show that the reaction between boninitic melt and harzburgite occurred in the supra-subduction zone. Although there is evidence from whole-rock major and trace element contents of the studied peridotite samples, some mobile elements were re-stabilized by serpentinization, and the general changes in these elements reflect the extensive characteristic features of mantle-derived peridotites. Considering the data as a whole, it can be said that the textural features, chemical diversity of the major minerals, and whole rock geochemical properties of this harzburgite-dunite assemblage are good examples for the interpretation of petrological processes and geotectonic implications in supra-subduction zones (SSZ).

Tracing The Source And Origin Of Earthenware Stove In Kelantan State Museum By Means Of Geochemical And Mineralogical Methods

This study applies geochemical and mineralogical methods to determine the source and origin of the raw materials used to manufacture the earthenware stove in Kelantan State Museum, Kota Bharu. The stove is claimed to be the most unique pottery made in Kelantan but details regarding its place of manufacture and technology are missing due to the poor recording and cataloguing system used by the museum in the past. Three analytical methods employed in this study were X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Thermogravimetric (TGA) analyses. The results of the analyses were compared with the compositional data of raw clay samples obtained from Sungai Galas and Tumpat, two well-known traditional pottery manufacturing localities in Kelantan. In addition, clay samples from Ulu Kelantan were also included in this study to check whether the stove has any similarity with the chemical contents of prehistoric pottery found in the Nenggeri Valley of Kelantan. The results of the analyses showed that the composition of the earthenware stove has closer similarity with the clay samples extracted from Sungai Galas compared to the samples from Tumpat and Ulu Kelantan. Major minerals found between the earthenware stove and clay from Sungai Galas are quartz, albite, muscovite, microcline and cordierite. Furthermore, Thermogravimetric analysis confirmed that the stove was fired below 600 °C, corresponding to the traditional bonfire-firing technique employed by the Mambong potters in Sungai Galas. On the basis of geochemical and mineralogical results, this study concludes that the earthenware stove in the Kelantan State Museum is a product of Kampung Mambong made of clay sourced from Sungai Galas and fired at low temperatures between 400 – 600 °C, probably using the open-firing technique.

Using Process Mineralogy as a Tool to Investigate Blending Potential of the Pentlandite-Bearing Ores at the Nkomati Ni Mine in South Africa

The mineralogy and texture of Ni-sulfide ores at the Nkomati nickel mine are highly variable, and this results in often erratic nickel recovery at the mine. The variability of the ore presents an opportunity to study the influence of grind size on the flotation-based recovery of Ni in highly heterogeneous sulfide ores, which would be applicable to this ore type at many other mines worldwide. In view of this, a process mineralogy investigation was conducted on thirteen mineralogically and texturally different nickel-sulfide ores from the Nkomati Nickel Mine, with a view on the influence of grind size on the flotation performance of pentlandite. Ore types presented include medium- and high-grade variants of the bleb, disseminated, massive, semi-massive, and net-textured sulfide ores of the Main Mineralized Zone (MMZ), as well as disseminated chromite-rich nickel sulfide ore and massive chromitite ore of the Peridotitic Chromitite Mineralized Zone (PCMZ). Laboratory scale metallurgical test work, comprising of sequential grinding and bench-top flotation testing of the ores, was conducted in combination with quantitative mineralogical investigation of the flotation feed and associated flotation products, using a FEI 600F Mineral Liberation Analyzer. The ore types under consideration require a variety of grind sizes (i.e., milling times) in order to attain optimal recovery of nickel through flotation. This is predominantly controlled by ore texture, and also partly by the abundance of the major constituent minerals in the ore, being pyroxenes, base metal sulfides, and chromite. Liberation of pentlandite is directly correlated with grind size (milling time), which is also positively correlated with the level of nickel recovery through flotation. A grind size of P80 at 75 µm results in the highest concentrate nickel grades of 7.5–8.1% in the PCMZ ores’ types which is the current grind for the PCMZ ores at Nkomati. A grind size of P77 at 75 µm yields the best overall pentlandite liberation, Ni recoveries of 84–88% and grades of 5.3–5.6% in the MMZ ores. This holds the potential to produce the best overall pentlandite liberation, nickel grades, recoveries from blending the MMZ and PCMZ ore types, and milling the composite ore at a target grind of P80 at 75 µm.

Characterization of deposited dust and its respirable fractions in underground coal mines: Implications for oxidative potential-driving species and source apportionment

Oxidative potential (OP) is considered to be an efficient indicator of particulate matter (PM) to induce oxidative stress in the lungs and is increasingly considered to be a relevant health metric. In this study, two complementary OP assays were deployed, including dithiothreitol (DTT) and ascorbic acid (AA) assays, to investigate the potential toxicity (as generators of oxidative stress) of respirable fractions (DD4, < 4 μm) of deposited dust (DD500, < 500 μm) in underground low-S and low-pyrite coal mines in Henan Province, Central China. The OPDTT of DD4 is higher than that reported for other types of atmospheric PM, whereas the OPAA of DD4 is similar and/or slightly higher. Cross-correlation and multilinear regression analyses are applied using datasets of major mineral and geochemical patterns in the DD4 samples and the respective OP values to identify the major drivers for OP in respirable coal dust. Thereafter, the patterns of DD4 are compared with those of DD500 and the parent coals to determine the sources of OP-relevant substances. OPDTT is mainly governed by some trace elements (Sb, As, Li, B, Sr, and Pb) and minor minerals (anatase, quartz, siderite), and their synergistic effect may be one of the reasons for the high DTT consumption. For OPAA, quartz, total clay (sum of illite, kaolinite, tobelite, and clinochlore) and Ni, Cr, Co, Si, and S, play an important role in regulating the OPAA of pyrite-free DD4 samples. These OP-relevant substances have three sources: coal dust, which has a similar composition in DD4, DD500, and the parent coal (such as siderite and its associated elements); gangue dust, which does not occur in the parent coal but is widely detected in DD4 and DD500 (such as quartz, kaolinite, and relevant elements); and cement dust (from gunite galleries), which is mainly calcite- and calcite-associated elements.

Assessment of Bioactive Compounds, Physicochemical Properties, and Microbial Attributes of Hot Air–Dried Mango Seed Kernel Powder: an Approach for Quality and Safety Evaluation of Hot Air–Dried Mango Seed Kernel Powder

The presence of carbon and nitrogenous compounds in mango processing by-products makes them excellent substrates for the biosynthesis of many microbial metabolites using fermentation processes. Pretreatment of the substrate with retention of crucial growth supporting compounds is vital for designing and optimizing fermentation media for enhanced production of desired metabolites. The present study investigated the effect of hot air drying (HAD) (50, 60, 70, and 80 °C) on the bioactive compounds, physio-chemical and mineral profile, fermentable sugar, and microbial safety of mango (cv. chausa) seed kernel powder. Results indicated that different drying temperatures non-significantly (P<0.05) affected the carbohydrates, starch (except at 60 and 80 °C), nitrogen, and protein content. The pH (except at 70 °C), total phenolics, and antioxidant activity decreased with an increase in drying temperatures. Inductively coupled plasma–optical emission spectrometry (ICP-OES) analysis revealed the increase in concentrations of majority minerals with incremental drying temperature. The microbial load of powdered seed kernel after 30 days of room temperature storage was within safe limits, as samples were devoid of food pathogens. Briefly, the study suggests HAD (at 70–80 °C) to convert mango kernels into stable powdered form for prolonged storage. The powdered kernels can be utilized in diversified food industry and as a feedstock (with safe storability, preserved bioactive, mainly carbon and nitrogen compounds) for biosynthesis of valuable metabolites via microbial fermentation route.

Geochemical partitioning and spatial distribution of heavy metals in soils contaminated by lead smelting

Heavy metals (HMs) pollution is a universal and complex problem at lead smelting sites. Further understanding on the distribution, coexistence relationship and occurrence form of multi-metals in soils should be taken prior to restoration on the contaminated sites. In this study, 222 soil samples in a typical abandoned lead smelting site were investigated to understand the spatial distribution and geochemical partitioning of HMs. The results showed that soil quality was seriously threatened by As, Pb and Cd, which expressed high spatial heterogeneity. Integration of sequential extraction, X-ray photoelectron spectroscopy and mineral liberation analysers were employed to qualify the geochemical partitioning of HMs. The data showed that Pb and As were mainly partitioned in the reducible phase and residue phase, where the maximum of As were 18% and 79%, and the maximum of Pb were 31% and 64%, respectively, whilst Cd was mainly partitioned with residue phase (about 25%) and weakly acid soluble phase (about 18%). Paulmooreite was the major important mineral host for Pb and As, whereas Cd predominantly existed in willemite. These minerals containing HMs could usually with Fe reside in the octahedral layer of clay minerals such as montmorillonite, and may also reside in the interlayer. Quartz, montmorillonite and goethite were closely associated with HMs minerals in contaminated soils, which limited vertical migration of HMs and potential risks to groundwater. The results enhanced the understanding of spatial distribution and occurrence behavior of HMs, whilst providing potential benefits to heavy metal stabilization and risks control at abandoned non-ferrous metal smelting sites.

Valorization of copper smelter slag through the recovery of metal values by a synergistic bioprocess system of bio‐flotation and bio‐leaching

AbstractSlag sample generated as solid waste from a copper plant in Southern Africa contains strategically important base metals like copper, nickel and cobalt. X‐ray diffraction and X‐ray fluorescence analysis confirmed the presence of fayalite (Fe2SiO4), silica (SiO2) and alumina (Al2O3) as the major mineral phases in the slag sample. The presence of alumina and silicate minerals in copper slag are the major obstacles in the recovery of base metals in mineral processing industries. The copper slag may be hazardous if abandoned to the environment but it may be a valuable resource if the metal values can be recovered. Hence, the present study focused on the application of a bio‐surfactant extracted from Lactobacillus fermentum bacterium as a bio‐collector in the flotation of the slag sample to reduce its silica and alumina content. Subsequently, the slag sample was subjected to bio‐leaching by Acidithiobacillus ferrooxidans bacterium for recovery of the metal values. Flotation batch experiments were conducted in 1 L scale Denver flotation cell and during the process, about 37.90% of silica and 22.82% alumina were removed from the slag sample. The findings from this study further revealed the effectiveness of the bio‐surfactant‐assisted flotation process on the bio‐leaching of base metals from the slag sample. Flotation of silica and alumina from the slag improved bio‐leaching performance and recovered about 74.0% of copper, 60.0% of nickel and 33.4% cobalt in the bio‐leaching process conducted at laboratory scale.

Zircon crystallization in low-Zr mafic magmas: Possible or impossible?

Zircon is a ubiquitous accessory phase that carries important isotopic and geochemical information. Experimental work indicates that zircon solubility in silicate melts increases exponentially with decreasing silica; accordingly, crystallizing mafic magmas would only precipitate zircon from the last drops of residual melts, likely of granophyric composition. However, this view is inconsistent with the abundance of syn-magmatic zircons in many mafic rocks, in which zircon often occupies textural positions compatible with early crystallization. Given that factors other than temperature and magma composition negligibly affect the solubility of zircon, its precipitation from mafic magmas must involve the formation of small zircon-saturated transient zones. Here we explored that possibility using 2D finite elements to model the crystallization of MORB melts confined in pores. We found that zircon-saturated volumes may form locally at the growing mineral-melt interfaces if the growth rate of a low KdZr mineral (<0.2) is much faster than the diffusion rate of the rejected Zr4+ away into the melt, thus leading to the precipitation of zircon in low-Zr mafic magmas. Local saturation close to interfaces growing in confined pores also explains the wide range of crystallization temperatures displayed by zircons of mafic rocks, the variety of their inclusions and textures, and in the particular case of the Atlantic seafloor, why syn-magmatic zircons are more common in troctolites and olivine gabbros than in the more evolved clinopyroxene or amphibole-rich gabbros. This mechanism can also account for the formation of other accessory phases composed of elements scarcely partitioned in major minerals.

Gemological Characteristics and Chemical Composition of a New Type of Black Jadeite and Three Imitations

Because of the increasing price of jadeite, many fake species have appeared on the market. We recognized three pieces of fake black jadeite that had been placed among real black jadeite. In this study we conducted a mineralogical investigation of the three fakes and the real jadeite by using FTIR and XRD techniques; in addition, we performed in situ major, minor and trace element chemical characterization based on EPMA-WDS and LA-ICP-MS techniques. The three imitations have different components, dominated by katophorite (97%), augite (66%) and anorthite (97%). In contrast, the real jadeite sample contains more than 99% jadeite. Unlike previous reports on black jadeite, the dark omphacite exsolution around the jadeite cleavage is the chromogenic factor in the present study, whereas the black color of the imitations comes from light absorption by major melanocratic minerals and widespread fine graphite. We propose that 2–4 sharp bands between 600 and 800 cm−1 of FTIR and the 2.42 and 2.49 Å peaks of XRD can be used to discriminate black jadeite from imitations. Even though natural jadeite deposits are being exhausted, materials of the three natural imitations were determined not to be suitable for jewelry due to low hardness, widespread occurrence and unknown injury of the radioactive elements thorium and uranium. Otherwise, they could enhance value and be ideal for large-sized ornaments of fine design.

Machine Learning Investigation of Clinopyroxene Compositions to Evaluate and Predict Mantle Metasomatism Worldwide

Plain Language SummaryClinopyroxene is a major mineral in Earth's upper mantle. Previous studies have attempted to discriminate between reactions modifying the mantle by plotting clinopyroxene major and trace element compositions in two‐dimensional (2‐D) diagrams. However, these 2‐D methods show poor accuracy when applied to global datasets. Therefore, we suggest a machine learning approach to evaluate clinopyroxene compositional data in higher dimensions. Our results demonstrate that machine learning can significantly improve the accuracy of clinopyroxene compositional predictions over classical methods utilizing elemental ratios. Furthermore, the application of our algorithm to a global clinopyroxene dataset suggests that mantle metasomatism is globally widespread.

Single-crystal elasticity of (Al,Fe)-bearing bridgmanite up to 82 GPa

AbstractThermoelastic properties of mantle candidate minerals are essential to our understanding of geophysical phenomena, geochemistry, and geodynamic evolutions of the silicate Earth. However, the lower-mantle mineralogy remains much debated due to the lack of single-crystal elastic moduli (Cij) and aggregate sound velocities of (Al,Fe)-bearing bridgmanite, the most abundant mineral of the planet, at the lower mantle pressure-temperature (P-T) conditions. Here we report single-crystal Cij of (Al,Fe)-bearing bridgmanite, Mg0.88Fe0.1Al0.14Si0.90O3 (Fe10-Al14-Bgm) with Fe3+/ΣFe = ~0.65, up to ~82 GPa using X-ray diffraction (XRD), Brillouin light scattering (BLS), and impulsive stimulated light scattering (ISLS) measurements in diamond-anvil cells (DACs). Two crystal platelets with orientations of (–0.50, 0.05, –0.86) and (0.65, –0.59, 0.48), that are sensitive to deriving all nine Cij, are used for compressional and shear wave velocity (νP and νS) measurements as a function of azimuthal angles over 200° at each experimental pressure. Our results show that all Cij of singe-crystal Fe10-Al14-Bgm increase monotonically with pressure with small uncertainties of 1–2% (±1σ), except C55 and C23, which have uncertainties of 3–4%. Using the third-order Eulerian finite-strain equations to model the elasticity data yields the aggregate adiabatic bulk and shear moduli and respective pressure derivatives at the reference pressure of 25 GPa: KS = 326 ± 4 GPa, µ = 211 ± 2 GPa, KS′ = 3.32 ± 0.04, and µ′ = 1.66 ± 0.02 GPa. The high-pressure aggregate νS and νP of Fe10-Al14-Bgm are 2.6–3.5% and 3.1–4.7% lower than those of MgSiO3 bridgmanite end-member, respectively. These data are used with literature reports on bridgmanite with different Fe and Al contents to quantitatively evaluate pressure and compositional effects on their elastic properties. Comparing with one-dimensional seismic profiles, our modeled velocity profiles of major lower-mantle mineral assemblages at relevant P-T suggest that the lower mantle could likely consist of about 89 vol% (Al,Fe)-bearing bridgmanite. After considering uncertainties, our best-fit model is still indistinguishable from pyrolitic or chondritic models.

Romania’s Perspectives on the Transition to the Circular Economy in an EU Context

The main objective of the paper is to highlight Romania’s perspectives on the transition process towards the circular economy, in respect with the tendencies registered at the level of the European Union. To this end, our methodology involved the selection of four indicators, each one being viewed as representative for one area of interest specified in the circular economy monitoring framework established by the European Commission, namely: Generation of waste excluding major mineral wastes per domestic material consumption; Recycling rate of municipal waste; Circular material use rate; Gross investment in tangible goods—percentage of gross domestic product. On the basis of data series provided by the Eurostat database, our study employed a quantitative approach, by using the econometric analysis of time series. For each selected indicator, time series-specific approximation and prediction models were constructed; against this background, we were able to reveal accurate forecasts of the analysed variables, with respect to different time horizons. Detailed analysis of the data series resulting from the research proved that on the long run, there are favourable premises for improving Romania’s performance in adopting the circular economic model, on the basis of low values for the indicator “Generation of waste excluding major mineral wastes per domestic material consumption”, of an ascending trend for the indicator ”Circular material use rate” and of maintaining the values of the “Gross investment in tangible goods—percentage of gross domestic product” indicator above the EU-27 average.

Mineral Content and Antiurolithiatic Analysis of Horse Gram Flour

Macrotyloma Uniflorum is commonly known as horse gram. It is found in India, Africa, Australia, and Srilanka. It is reported to have pharmaceutical applications like antioxidant, anticancer, and anti-diabetic. The present paper provides the information about the utility of horse gram as a cheap source of mineral content with anti-urolithiatic property. The phytochemical analyses were also carried out to determine the presence of secondary metabolites. Horse gram powder contains macro nutrients and micro nutrients. Calcium is the major mineral content followed by potassium. The studies suggest that the utilized natural biomass could be tapped as a source of mineral and carbohydrates. Horse gram seed powder comprises of highest carbohydrate content followed by phenol, sterol, terpenoid, and protein. Bio encapsulated Ag nano particles showed highest dissolution of struvite stones as compared to aqueous and ethanol extracts. Hence it could be suggested as a major ingredient in functional food.

Mineralogy and geochemistry of lavas from the submarine lower caldera walls of Santorini Volcano (Greece)

Santorini Volcano, located in the central sector of the South Aegean volcanic arc, is one of the most active and potentially dangerous volcanoes in Europe. It has hosted Plinian eruptions over the last 350 ka of which at least four eruptions were accompanied by caldera collapses. Even though Santorini Volcano is considered a major threat, the main focus of research, thus far, has been on the comparatively young and subaerial deposits, whereas older stages of volcanism have been poorly studied. Our study focusses on samples from the submarine inner caldera walls and gives new insights into the early evolutionary stages of Santorini Volcano, contributing to a better understanding of its eruptive history and thus potential risks. The submarine lava successions were sampled along the inner caldera wall by a remotely operated vehicle (ROV) during R/V POSEIDON cruise 511 in 2017.The recovered lavas comprise two magmatic series, a low-K basaltic series overlain by a medium- to high-K series, which includes basaltic andesites, andesites and occasional dacites to trachytes. Major and trace element compositions and mineral zonation patterns suggest that fractional crystallisation and periodic magma replenishment were the dominant processes controlling magma evolution of both magmatic series. In addition, repeated magma mixing events played an important role, as indicated by zonation patterns in plagioclase and clinopyroxene ante- and phenocrysts. The thickness of the submarine lava successions (≥100 m) and the occurrence of similarly zoned plagioclase throughout indicate long-lived magma plumbing systems characterised by repeated differentiation and magma mixing. Furthermore, the incompatible element and radiogenic isotope ratios indicate a heterogeneous mantle source for Santorini magmas, which reflects the relative contribution of subduction (sedimentary) input and mantle wedge influx. A lava sample from the northern submarine caldera wall probably represents a deep level of the original Peristeria volcano. 40Ar/39Ar dating of andesite lavas from the southern submarine caldera produced ages of ~255 ka, whereas one basalt lava produced an age of 309 ± 30 ka. Interestingly, the new ages of both groups fall within an age gap in the volcanic history of Santorini Volcano. Even though it was not possible to unequivocally correlate the sampled submarine lava series to known subaerial units, the major and trace element compositions, and Sr-Nd-Pb isotopic compositions of our intermediate lavas show a strong similarity to subaerial lavas of Peristeria volcano, the second oldest major stage of Santorini volcanism. It however seems more likely that we have sampled a thus far unknown stage of volcanism at Santorini Volcano.

Low-grade chalcopyrite ore, heap leaching or smelting recovery route?

Chalcopyrite, the major mineral source of copper, is commonly treated pyrometallurgically, using froth flotation, smelting, converting and electrorefining processes. The ore treatment however is limited to the cut-off grade concentration below which the extraction is not economically viable. In this study a comparison of feasibility of the pyrometallurgical and hydrometallurgical treatment of low grade (0.23%–0.35% Cu), high content chalcopyrite (>90% CuFeS2) ore were studied from both technical and economic viewpoints. On a technical stance, the results of a pilot test on froth flotation of 100 t of low-grade ore are presented. The pilot test results confirm the generation of a Cu concentrate of a grade range 23.3–19.6% Cu with a copper recovery in the range 90.9–78.1%. For the hydrometallurgical treatment, bio heap leaching of 40,000 t of low-grade ore using agglomeration and aeration was proven to achieve a copper recovery of 32.6% for the chalcopyrite portion of the ore over 326 days of operation.On the economic side, the operating cost of the process per tonne of copper cathode for both processes were reported. The operating cost for the pyrometallurgical (PM) processing plant was calculated to be 1.4 times less than the hydrometallurgical (HM) processing plant. The sales revenue of the PM route was also higher than that of the HM route due to the byproducts credit. Capital cost estimates were made assuming that the current solvent extraction/electrowinning (SX/EW) facilities in a HM route and the current smelting and electrorefining plants in the PM route have enough free capacity to absorb the upstream outputs. Applying the copper extraction efficiencies of the pilot plants, the profitability indicators for both routes in treatment of 3000,000 t ore/year was studied. The impact of the interest rate was found significant in economic preference of the HM route over the PM route. This is due to the high capital cost of the mineral processing plant despite of the higher operating cost of the HM plant. The capital cost of the mineral processing plant can make the HM route feasible at interest rates higher than 27.5%. At discount rates lower than 27.5%, the PM route process is viable over the HM route at copper market price of US$9500/t. A drop in copper selling price to US$6000/t acts in favor of the HM route, making it feasible at interest rates higher than 22.4%. For a general scenario where the construction of SX/EW and smelter/refinery plants are required, the discount rate at which the net present value (NPV) of the two routes are equal has decreased from 27.5% to 17%. In this scenario, for discount rates higher than 17%, the HM route with 31% total copper recovery is more feasible than the PM route with 79% recovery.

A Synopsize Report of the Various Perspectives of Urolithiasis and its Ethno-Medical Future

Kidney stone formation or urolithiasis is a complex process that results from a series of physicochemical events, including supersaturation, nucleation, growth, aggregation, and retention in the kidney. Urolithiasis affects about 10% of people in the Western world in their 70s. Epidemiological data show that calcium oxalate is the major mineral in most kidney stones.&#x0D; To date, great progress has been achieved in identifying metabolic risk factors that predispose to this complex condition, the most prominent of which is hypercalcemia. The unique genetic and epigenetic elements concerned in urolithiasis have remained largely unknown, thanks in part to the candidate gene and linkage techniques that have been available to date, which are inherently low in terms of their decision-making power and ability to assess modest outcomes in complicated traits.&#x0D; However, when combined with studies of rare Mendeliantypes of urolithiasis linked to various metabolic danger factors, those methodologies have shown organic pathways that appear to underpin the improvement of stones in the urinary system. Furthermore, despite substantial improvements in research into the biochemical and physical signs of kidney stones, therapeutic therapy medications are in short supply. Phytotherapy may be effective as an alternative or adjunctive therapy in the treatment of urolithiasis, according to data from in vitro, in vivo, and clinical investigations. This article discusses the various varieties of stones, as well as their characteristics.&#x0D; The varieties of stones, their composition, clinical evaluation, various surgical procedures for removal, treatment downsides, and several herbal medicine details giving therapeutic effects are all included in this review.&#x0D; Keywords: Urolithiasis, Epidemiological data, Diagnosis, Herbal drugs, Ethno medicines.

Thermal-Infrared Spectral Feature Analysis and Spectral Identification of Monzonite Using Feature-Oriented Principal Component Analysis

Rock spectral analysis is an important research field in hyperspectral remote sensing information processing. Compared with the spectra in the short-wave infrared and visible–near-infrared regions, the emittance spectrum of rocks in the thermal infrared (TIR) region is highly significant for identifying some major rock-forming minerals, including feldspar, biotite, pyroxene and hornblende. Even for the same rock type, slight differences in mineral composition generally result in varying spectral signatures, undoubtedly increasing the difficulty in discriminating rock types on the Earth’s surface via TIR spectroscopy. In this study, amounts of monzonite samples from different regions were collected in the central part of Hunan Province, China, and emission spectra at 8–14 μm were measured using a portable thermal infrared spectrometer. The experimental result illustrates 13 remarkable feature positions for all the monzonite samples from different geological environments. Furthermore, by combining the extracted features with the principal component analysis (PCA) method, feature-oriented PCA was applied to establish a model for identifying monzonite accurately and quickly without performing spectral library matching and spectral deconvolution. This study provides an important method for rock type identification in the TIR region that is helpful for the rock spectral analysis, geological mapping and pixel unmixing of remote sensing images.

Technology, geography, and diversification in a small mineral economy

When should a policymaker promote economic diversification in resource-rich regions? What are the necessary structural economic conditions for such policies to work? How compatible are regional and national strategies of diversification? This study focuses on the general equilibrium properties of policies that aim to diversify the economic structure of regions through productive linkages with the resource sector. Using Chile, a major mineral exporter, as a case study, and exploiting variation induced by the expansion of the mining industry and the commodity prices super-cycle, we analyze how a shock in the resource sector affects other sectors and regions through productive linkages. The results are utilized in simulating the economic conditions under which regional diversification is an optimal strategy for resource-based economic development. Our results support the need for a multiscalar approach for resource-driven economic development policies by showing that optimal outcomes of diversification policies on economic growth are found when policies combine regional, sectoral, and national strategies for development.