Periodico di Mineralogia

Geochronological and Petrogenesis of the Late Paleozoic Granitoids: in Sakarya Zone (Sarıcakaya-Türkiye)

2026-03-23T16:45:39+00:00

This study aims to elucidate the origin and geodynamic setting of the Late Paleozoic granitoid (Sarıcakaya magmatic complex) of the Sakarya Zone by examining its petrographic, geochemical, geochronological, and tectonic characteristics. Based on field and petrographic observations, the intrusive suite was identified as gabbro, diorite, granodiorite, granite, and pegmatite. Major and trace element analyses reveal that these rocks exhibit high K-bearing calcium-alkaline, metaluminous, and I-type granitoid characteristics. Major and some minor element discrimination diagrams indicate that plagioclase, hornblende, and biotite play a significant role in fractional crystallization. Discrimination diagrams (Th/Nb, Ta/Yb-Th/Yb, Nb/Y-Th/Y) indicate a crustally contaminated, subduction-modified, enriched mantle source. Increasing Zr/Nb ratios support these interactions and ongoing magmatic differentiation. Tectonomagmatic discrimination diagrams indicate that the samples are within the volcanic arc granite (VAG) domain. U-Pb zircon dating yields ages between 321.3±1.2 Ma and 323.6±0.9 Ma, corresponding to the Late Carboniferous and Early Carboniferous periods. Chondrite-normalized REE models show LREE enrichment relative to HREEs and a negative europium anomaly attributed to plagioclase fractionation or crustal assimilation. The data indicate that the magmatic rocks of Sarıcakaya represent the southward subduction of the Paleotethys Ocean during the Permian-Carboniferous period.

The role of calcium-based additives in extracting iron from red mud through carbothermic reduction

2026-02-26T11:03:33+00:00

Increasing aluminum demand has increased the red mud, a bauxite residue of the Bayer process. It contains valuable elements, such as iron, titanium, vanadium, and a small amount of rare-earth elements. Utilization of red mud is required to prevent environmental damage. In this work, the carbothermic reduction was followed by magnetic separation of red mud to extract iron. The effects of calcium-based additives, i.e., CaCl2 and CaF2, on recovery and metallization degree, as well as on phase transformation and morphology of iron particles in reduced pellets, were investigated. The red mud, coal, and additives were mixed homogeneously and pelletized into a diameter of 10 mm. The reduction process was carried out in a muffle furnace at 1050-1250 °C for 60 minutes. Furthermore, the reduced pellet was ground and a magnetic separation process was conducted to separate the iron metal from its gangue. The results showed that CaF2 performed better than CaCl2. The optimum result was obtained by adding 8% CaF2 and a 1.0 stoichiometric amount of coal to the carbothermic reduction of red mud at 1250 °C for 60 minutes. It generated iron grade, recovery, and metallization of 83.64%, 98%, and 93.5%, respectively.

Sodic amphibole zoning as a petrologic indicator of fenitisation in trachyandesites of the Lichi volcanics, Eastern Himalaya

2025-11-05T13:19:26+00:00

The vestiges of the Kerguelen plume-related magmatism that affected a large part of Eastern India during the Gondwana breakup are also preserved in the Eastern Himalaya. The Lichi volcanics, which are a consequence of the Kerguelen mantle plume activity, are exemplified by basalts, trachyandesites, and trachytes occurring in association with the Gondwana sediments of the Eastern Himalaya. Amphiboles are present in both the studied trachyandesites and trachytes; however, in the trachyandesites, the amphibole compositions range from sodic-calcic (richterite and katophorite) to sodic varieties (riebeckite and arfvedsonite). Sodic amphibole occurs as reaction rims that envelop the pre-existing sodic-calcic amphibole grains. The trachytes are sanidine-bearing, comprising numerous sanidine phenocrysts and are vesicular in nature. Geochemical characteristics of the studied rocks point towards the role of fractional crystallisation for the generation of trachyandesites and trachytes. The presence of calcite and zoned amphiboles along with high alkali contents (Na2O+K2O) and high Ba, Sr values indicate the post-magmatic alteration of trachyandesites by fenitising fluids. Hydrothermal alteration in alkaline complexes is driven by the process of fenitisation. Fenitising solutions enriched in Na, Ca, and volatiles (mainly CO2) have led to the replacement of sodic-calcic amphibole by sodic amphibole along with the crystallisation of calcite in the trachyandesites. The study attempts to understand the magma chamber processes responsible for the development of zoning characteristics in amphibole, the role of fenitisation, and the possible source of these fenitising solutions.

Evaluation of clay adsorption and plant-assisted nickel removal in ultramafic soils

2026-01-28T15:40:50+00:00

Nickel (Ni)-rich ultramafic soils present significant environmental and agricultural challenges due to the high bioavailability and toxicity of Ni. This study evaluated whether natural clay amendments could reduce Ni availability in ultramafic agricultural soils and consequently limit Ni uptake by the hyperaccumulator Odontarrhena chalcidica. Natural clays collected from Rubjekë (Durrës, Albania) were characterized by X-ray diffraction, showing a composition dominated by smectite (30%), illite (30%), and chlorite (34%). In batch adsorption experiments, Ni extracted from ultramafic soil of Tropoja was brought into contact with the natural clay from Rubjekë, where clays immobilized up to 95% of Ni with an adsorption capacity of 6.6 mg g-1 (R²=0.9993), following the pseudo-second-order model. An ex-situ pot experiment using Tropoja soil tested four clay doses (0-64 g kg-1). Clay amendment significantly reduced Ni availability, lowering Ni concentration in the soil solution by up to 80.4% and the bioavailable fraction to 15% of the initial value at the highest application rate. In the presence of Odontarrhena chalcidica and with soil amended with 1.07%-3.2% clay, Ni concentration in the soil solution decreased by 25.4-86.5%, while the bioavailable fraction declined by 12.3-19.4% in the first harvest. Furthermore, clay application markedly reduced Ni bioaccumulation in O. chalcidica while enhancing plant biomass production. Mineralogically active aluminosilicate clays effectively reduced Ni mobility and plant uptake while enhancing growth, demonstrating their potential as a sustainable solution for managing Ni-contaminated ultramafic soils.

Structural and thermal behaviour of epoxy coatings on thermoplastic substrates modified with zinc borate

2026-01-16T11:01:23+00:00

This study examined epoxy coatings reinforced with zinc borate (ZnB) applied on thermoplastic substrates derived from mixed household waste. The study aimed to combine experimental characterization with microstructure informed finite element modelling to evaluate the thermal behaviour and predicted mechanical response of mineral-filled epoxy coatings on heterogeneous waste-derived thermoplastics. The novelty of the work lied in integrating formulation optimization, surface characterization and SEM-informed simulation to investigate how mineral additives influence coating morphology, thermal stability and stress distribution in epoxy-coated sustainable thermoplastic systems. A Box-Behnken experimental design was employed to analyse the effects of shellac-allyl starch mixture (SAM), zinc borate and halloysite on coating film thickness. The statistical model demonstrated strong predictive capability with an adjusted R² value of 0.9637. Thermogravimetric analysis indicated that the decomposition temperature increased from 357.68 °C to 369.57 °C corresponding to a 3.3% increase in thermal stability. Contact angle measurements decreased from 55.38° to 39.83°. Finite element simulations were conducted to evaluate the influence of coating morphology on stress distribution and deformation behaviour. Under tensile loading of 2150 N, the predicted maximum displacement decreased from approximately 1.47 mm in reference coating to about 1.42 mm in coating containing ZnB, corresponding to 3-4% reduction in deformation. The combined experimental and simulation-based approach provided insight into the behaviour of mineral-reinforced epoxy coatings designed for sustainable thermoplastic substrates.

WinEudclas, a Windows program for eudialyte-group minerals

2026-03-22T17:36:52+00:00

A Microsoft® Visual Basic software, WinEudclas, has been developed to calculate the chemical compositions of eudialyte-group minerals based on data obtained from wet-chemical and electron-microprobe analyses. WinEudclas currently evaluates 32 valid mineral species using the Commission on New Minerals, Nomenclature and Classification (CNMMC) of the International Mineralogical Association (IMA) nomenclature scheme for the eudialyte-group minerals, with the general formula [N(1)N(2)N(3)N(4)N(5)]₃M1₆M2₃M3M4Z₃(Si₉O₂₇)₂(Si₃O₉)₂Ø_4-6X1X2. The program recalculates and estimates the chemical formulas of eudialyte-group species based on 72 oxygen atoms, with the total of Si+Al+Ti+Zr+Hf+Nb+Ta+W = 29 atoms per formula unit normalization approach. WinEudclas operates in five stages: (1) it estimates cation and anion contents provided by input chemical data; (2) it determines the zirconium- and zirconium-titanium eudialytes; (3) it assigns the Ca-rich and Ca-poor eudialytes; (4) it specifies the eudialyte subgroups and eudialyte series along with various variants; and (5) it classifies the eudialyte-group species into an appropriate group and series such as ferrokentbrooksite subgroup and feklichevite series. WinEudclas allows users to: (1) enter up to 40 input variables for mineral-chemical analyses; (2) type and load multiple eudialyte group mineral compositions in the data entry section; (3) edit and load the Microsoft® Excel files used in calculating, classifying, and naming the eudialyte-group minerals, and (4) store all the calculated parameters in the output of a Microsoft® Excel file for further data evaluations. The program is distributed as a self-extracting setup file, including the necessary support files used by the program, a help file, and representative sample data files.

Flow-through dissolution of mineral fibres under lysosomal conditions

2026-03-08T17:06:44+00:00

Mineral fibre toxicity is widely considered to depend on their residence time in the lungs, and therefore on their biodurability. However, fibre dissolution is typically examined in closed batch systems, which evolve toward saturation and do not reproduce the continuous renewal of lung fluids. In this study, for the first time the dissolution behaviour of fibrous antigorite, chrysotile, and crocidolite was investigated in a flow-through system to better constrain their expected persistence in vivo. Flow-through experiments were conducted in simplified artificial lysosomal fluid (sALF) at pH 4.5 and 37 °C, with a flow rate of 0.047 mL min^-1. The concentrations of dissolved elements were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), while the incubated samples were analysed by powder X-ray diffraction (PXRD). Released Si was used to derive steady-state dissolution rates normalised to specific surface area. Fibrous antigorite and chrysotile show comparable Si-release rates of 1.03±0.02∙10^-10mol m^-2s^-1and 1.09±0.11∙10^-10mol m^-2s^-1, one order of magnitude higher than that of crocidolite (1.22±0.06∙10^-11mol m^-2s^-1). When differences in specific surface area are considered, the biodurability of fibrous antigorite is only slightly lower than that of crocidolite, and therefore, both fibres are expected to persist significantly longer in vivo compared to chrysotile.