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  Subjects -> GEOGRAPHY (Total: 493 journals)
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Mineralogia
Journal Prestige (SJR): 0.272
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  This is an Open Access Journal Open Access journal
ISSN (Print) 1899-8291 - ISSN (Online) 1899-8526
Published by Sciendo Homepage  [389 journals]
  • Pollution sources and metallic elements mobility recorded by heavy
           minerals in soils affected by Cu-smelting (Legnica, SW Poland)

    • Abstract: Heavy mineral particles are widely used in Earth science studies to show sediment provenance and weathering conditions. Such particles are particularly useful in polluted soils surrounding mining and smelting facilities because heavy minerals are common by-products of these activities and may accumulate in the soils. As such, the particles are suitable indicators of metallic element carriers and their stability in the soil environment. In this study, we analyze heavy mineral particles in two soils surrounding the active copper smelter (Legnica, SW, Poland). We show that particles associated with different smelting activities dominate the heavy mineral fraction. We note the general absence of sulfides in the fraction indicating that these minerals might have been entirely dissolved, but timing of this dissolution is uncertain (before or after deposition within soils). Currently, the carriers of potentially toxic elements are mainly secondary Fe oxides. Studies aiming at better estimation of the proportion of metallic elements contained in heavy mineral particles are needed to fully use the potential of these phases in polluted soil studies. We estimate that Pb contained in Pb-rich silicate glass constitutes <0.5% of the total Pb budget and Pb contained in secondary Fe oxides is over 1% of the total budget, but these are minimal estimates.
      PubDate: Mon, 19 Feb 2024 00:00:00 GMT
       
  • Geological and Mineralogical Analysis of Phosphorites in the Jebel Dhyr
           Syncline, Eastern Algerian Atlas

    • Abstract: The characterization of phosphorite features within specific North African sedimentary series remains incomplete. Hence, the primary aim of this research is to determine the composition of powder patterns and phosphatic allochem fragments within the Jebel Dhyr syncline, situated in northeastern Algeria. By focusing on this region, the study endeavors to investigate the mineralogical properties and geochemical aspects of Paleocene-Eocene phosphorites in the broader context of North Africa. The methodology employed encompasses geological, petrographic, geochemical, and mineralogical analyses of the rocks. To achieve this objective, we have employed various techniques including thin section analysis, atomic absorption spectrometry, and X-ray diffraction (XRD). The geological section across the Jebel Dhyr area has revealed a succession of horizontally layered rocks. These rocks consist of eight prominent phosphorite layers interspersed with carbonate formations. Additionally, occasional thin layers of flint can be observed within these carbonate layers. XRD analysis of the whole rock established the presence of apatite group minerals such as hydroxylapatite, fluroapatite, francolite, and dahllite. Other minerals identified include carbonates, quartz, zeolites, feldspar, clays, sulphides, and gypsum. XRD recordings on the phosphatic allochem grains (pellets, coprolites, intraclasts, and shark teeth) identified different mineral phases, with coprolites and pellets showing hydroxylapatite and fluorapatite, sometimes associated with dahllite, while granules of different forms revealed hydroxylapatite associated with fluorapatite or francolite. Teeth from the Jebel Dhyr phosphate beam showed the systematic presence of fluorapatite. This study provides valuable information for the comprehensive utilization of phosphorus resources in the Algeria-Tunisia border.
      PubDate: Fri, 29 Dec 2023 00:00:00 GMT
       
  • Minerals discovered in Poland – a review

    • Abstract: Among nearly 6,000 minerals approved by the International Mineralogical Association (IMA), 34 have been discovered on Polish territory. The article describes the history of these discoveries and the procedure for submitting and approving new minerals. It is noted that the vast majority of the new species found in Poland were described by or in cooperation with Polish mineralogists. Three minerals from the list were described in the 19th century, and seven in the 20th century, while most discoveries took place as early as the 21st century. This is a result of (i) the new equipment acquired by the Polish research units enabling accurate structural and chemical studies of minerals, and (ii) fruitful cooperation between mineralogists from Polish and foreign research centers. This is a very labour-intensive and time-consuming process that is not always successful. It is clear that the discoveries of new minerals are important not only for sciences but also for the economy. They provide information on the mineral-forming processes and are the source of valuable elements (e.g. Nb, Ta - nioboholtite, żabińskiite; Tl- thalliomelane and Sc- scandio-winchite, heflikite) that are often critical in modern industries.
      PubDate: Fri, 29 Dec 2023 00:00:00 GMT
       
  • New synthetic [LREE (LREE = La, Ce, Pr, Sm), Pb]-phosphate phases

    • Abstract: Search for inexpensive and efficient methods of critical raw materials recovery is of great importance across the world due to growing demand for green technologies. Formation and detailed characterization of new Pb- and Light Rare Earth Elements (LREE)-containing phosphates, compared to already described Pb- or LREE-containing phosphates, was described in this work. These phases were precipitated at experimental conditions similar to these used in a newly proposed coprecipitation route for REE recovery from aqueous solutions. The formation of La, Ce, Pr and Sm phosphates from aqueous solutions proceeded differently in the presence of Pb than in its absence. No rhabdophane group minerals, (REE,Ca,Th)(PO4)·nH2O were formed, which were the product of crystallization in the absence of Pb, as evidenced by the PXRD analysis of the control LREE phosphates. Instead, a new, distinct phase was formed, which is neither a ‘phosphoschultenite’, PbHPO4, with La, Ce, Pr or Sm substitution nor a rhabdophane with Pb substitution. This showed that PbHPO4 structure did not accept isomorphic substitutions of LREE elements and rhabdophane structures are reluctant to accept Pb substitutions. At the same time, the formation of a hitherto unknown crystalline phase was found to be a mixed (LREE,Pb)-phosphate. A lower pH caused higher crystallinity of phases, as confirmed by SEM and PXRD. FTIR spectroscopy showed the hydrous nature of the obtained phases, which was additionally confirmed by thermal analysis. Decreasing pH of the reaction solution resulted in a higher crystalline water content. Moreover, La-bearing phases contained more chemically bound water than other phases. A combined EDS analysis and ICP-OES led to the chemical composition of new Pb phases with La, Ce, Pr and Sm that can be expressed as La2Pb3(PO4)4·3.5H2O, Ce2Pb3(PO4)4·3.3H2O, Pr2Pb3(PO4)4·3.1H2O and Sm2Pb3(PO4)4·3.3H2O, respectively. These results give a better understanding of potential novel recovery pathways of REE from phosphate mineral sources or wastes.
      PubDate: Tue, 19 Dec 2023 00:00:00 GMT
       
  • Thorite inclusions in zircon of the monzogranite, Lower Nubia, SW Egypt

    • Abstract: This report presents the results of a petrographical and mineralogical (optical microscopy, BSE-EDS image analysis) study of zircon in samples from the Lower Nubian monzogranite. The mineral occurs as smaller grains (< 80 μm) in a fine-grained quartz-feldspar-matrix, coexisting with other accessory minerals including biotite, clinochlore, titanite, and britholite-(Ce). Zircon is also present within biotite and britholite-(Ce), suggesting that it started crystallization at about the same time as these two minerals. Two types of thorite inclusions within zircon are reported in this study. Type 1 is widely distributed throughout the zircon grain, forming crystallites of which each is typically < 1 μm in size. Type 2 is relatively larger (5-15 μm) and occurs only in one part of the grain. For the thorite inclusions, three possible origins are briefly discussed: (1) exsolution of thorite from zircon; (2) dissolution/reprecipitation of zircon; and (3) growth syngenetically with zircon. Of these potential hypotheses, the syngenetic growth model seems more favorable for zircon-thorite intergrowths than the other two hypotheses. Thorite inclusions and their host zircons seem to have grown from magma rather than hydrothermal or supercritical solutions. Here, they have primary textures and consistent chemical compositions that are consistent with whole-rock geochemistry.
      PubDate: Tue, 19 Dec 2023 00:00:00 GMT
       
  • Synthesis and solubility of hopeite Zn(PO)·4HO

    • Abstract: Minerals from the phosphate groups are used in environmental engineering as thermodynamically stable vehicles for heavy metals such as zinc. The hopeite Zn3(PO4)2·4H2O was synthesized and characterized by X-ray diffraction and scanning electron microscopy. The solubility of the hopeite was measured at 25°C. The average solubility product, log Ksp, for the reaction Zn3(PO4)2·4H2O ⇔ 3Zn2+ + 2PO43- + 4H2O at 25°C is –35.72 ± 0.03. The free energy of formation, ΔG°f,298, calculated from this measured solubility product is –3597.4 ± 1.0 kJ mol-1. The immobilization of zinc in the hopeite structure offers the possibility of developing an effective method for removing Zn from wastewater, water and soils.
      PubDate: Mon, 18 Dec 2023 00:00:00 GMT
       
  • Mass transfer and element redistribution during chloritization of
           metamorphic biotite in a metapelite: insights from compositional mapping

    • Abstract: Fluid-driven reactions are common in the upper crust, leading to mineral replacement and element redistribution on a kilometer to a micron scale. One common fluid-induced reaction is the chloritization of biotite. Chloritization can lead to the production of multiple phases, such as K-feldspar, titanite, and rutile, depending on local chemistry and fluid composition. Here, we compare different approaches to mass balance calculations using an altered garnet-bearing metapelite collected from Ny Friesland, Svalbard Archipelago, Norway. In the outcrop, amphibolite facies schists are cut by joints that acted as fluid pathways that led to the development of a narrow (~5 cm) alteration zone. Alteration involved the replacement of biotite by chlorite + K-feldspar ± rutile ± titanite. Mass balance calculations based on whole-rock composition and assuming immobile Zr indicate the addition of H2O, Si, Ti, Fe, or Mg and the removal of K or Ca. In contrast, mass balance calculated for the pseudomorphic replacement of Bt by Chl + Kfs ± Rt ± Ttn using X-Ray maps for three focused areas indicates the removal of Si or Ti rather than addition. Moles of product phase and elements gained or lost during this reaction varies between individual areas. This variation suggests that fluid heterogeneity and local chemistry governed the progression of the replacement reaction. All the product phases involved in the biotite breakdown are geochronometers and/or geothermometers, providing new opportunities for the petrochronology of fluid-induced reactions.
      PubDate: Mon, 06 Nov 2023 00:00:00 GMT
       
  • Synthetic zeolite derived from coal fly ash decorated with magnetic
           alginate bead: Application to detoxification of arsenic and vanadium

    • Abstract: Heavy metal toxicity is highly demanding and challenging to clean up the pollutants. To recover the issues mentioned above, we propose a hydrothermal synthesis of zeolite (NaX-UP). Further surface modification by poly-ethylenimine (PEI) could turn to be amine-modified zeolite nanosheets (zeolite NSs) possessed plenty of hydroxyl and amino groups (Al-O, Si-O-Si, Si-OH and NH2) on their surface, decorated with magnetic nanoparticles (Fe3O4 NPs), that are enabled to bridge with inter and intramolecular hydrogen bonding an additionally electrostatic interaction might be a significant role. Further, this can be converted into magnetic bead crosslinking with sodium alginate immersed in an excess calcium chloride solution. The-as formed Fe3O4 NPs decorated amine modified zeolite alginate bead denoted to be (Fe3O4 NPs decorated @PEI-zeolite NSs alginate bead) upholding a significant advantage would aim to clean up the anionic pollutants are [As(V) & V(V)] from an aqueous solution.
      PubDate: Wed, 16 Aug 2023 00:00:00 GMT
       
  • Metamorphic dolomitic marble-hosted talc from the Mulvoj area in the
           Western Pamir Mountains, Tajikistan

    • Abstract: Talc is crystallized in the metamorphic dolomitic rocks of the southwest Pamir mountains in the Mulvoj area, Tajikistan. Field studies show that talc is restricted to metamorphic dolomitic marble layers in the garnet-mica schist and gneiss. The layers are parallel to the original sedimentary bedding and schistosity of the metamorphic rocks. Petrography and whole rock geochemistry reveal calcite, tremolite, quartz and dolomite as the main mineral phases in the talc-bearing metamorphosed dolomitic rocks, while calcite is absent in the samples without talc. XRD studies show that talc samples are almost pure, and geochemistry indicates very low Fe and Cr and very high Mg contents. Geochemical features along with field observations clearly shows that Mulvoj talc is not originated from peridotite. Based on phase relations studies in the CaO-MgO-SiO2-H2O-CO2 system, the reaction between dolomite, quartz, and water at pressure greater than 2 kbar and temperature up to ~460°C and XCO2 up to 0.6 was the main talc forming reaction. Talc and calcite consuming reaction produced tremolite, dolomite and binary (CO2-H2O) fluid.
      PubDate: Wed, 09 Aug 2023 00:00:00 GMT
       
  • Britholite-(Ce) from the metaluminous granite of SW Egypt

    • Abstract: Optical microscopy and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analyses were used to characterize britholite-(Ce) of the metaluminous granite (Proterozoic) intruded into the Nubian Formation in southwestern Egypt and having a relatively high content of radioactive elements (potassium = 4.4 wt%, thorium = 52 ppm, uranium = 10 ppm). The britholite-(Ce) studied here incorporates light rare earth elements (LREE) including lanthanum, cerium, praseodymium, and neodymium as well as thorium. The mineral forms as tabular crystals in a fine-grained quartz-K-feldspar-plagioclase matrix, coexisting with other accessory minerals including biotite, zircon, clinochlore, titanite, and magnetite. Primary britholite-(Ce) usually includes titanite, zircon, and magnetite and is occasionally included in biotite. The inclusion of britholite-(Ce) in biotite suggests that the two minerals crystallized approximately coevally. Petrographical and SEM-EDS data indicate breakdown of the primary magmatic britholite-(Ce) in the samples. This study constitutes the first report for a sole presence of britholite-(Ce) as LREE phase in metaluminous granite samples from Egypt.
      PubDate: Thu, 06 Apr 2023 00:00:00 GMT
       
  • Chrysoprase – history and present

    • Abstract: The authors present the history of chrysoprase discovery and the progress of knowledge about this material over the millennia, based on the extended review of world literature. Tracing the oldest archaeological artifacts from before 9,000 years, the lens of history turns on a stone that has not been properly identified mineralogically for centuries. In the 1830s, chrysoprase was finally included into the chalcedony group and its green color was associated, very correctly, with nickel compounds dispersed in its structure. After all, the most current mineralogy of chrysoprase is presented on the basis of the results of modern analytical studies. These data clearly indicate that chrysoprase is a mixture of several SiO2 polymorphs with varying degrees of structural order (opal, chalcedony, moganite, quartz). This radically changes the previous taxonomy of chrysoprase and its position in current mineralogical and petrographic systematics.
      PubDate: Fri, 24 Mar 2023 00:00:00 GMT
       
  • Early Devonian sinistral shearing recorded by retrograde monazite-(Ce) in
           Oscar II Land, Svalbard

    • Abstract: The Southwestern Basement Province of Svalbard extends northward from Sørkapp Land in the south to Oscar II Land. In the north, the Müllerneset Formation characterized by polymetamorphosed Proterozoic sedimentary rocks crops out. In this study we used an integrated tectonic and petrochronological approach to gain an insight into the structural and metamorphic evolution of the unit and surrounding basement. The Müllerneset Formation consists of two separate tec-tonic blocks. NNW-SSE trending retrograde foliation is associated with mineral and stretching lineation and kinematic indicators consistent with left-lateral to oblique sinistral shearing in the western block. The eastern block is characterized by the opposite sense of shear that was overturned during the Eurekan event as evidenced by unconformably overlaying Carboniferous sedimentary rocks. Conventional geothermobarometry yields the prograde peak pressure metamorphic conditions of 6.6 - 7.1 kbar at 480 - 520°C followed by peak temperature at 5.1 - 5.9 kbar and 530 - 560°C. Subsequent retrograde greenschist facies overprint is related to left-lateral NNW-SSE trending shearing. Tiny monazite occurs within foliation or overgrows allanite-(Ce), thus is interpreted as growth along a retrograde path. Th-U-total Pb dating of monazite-(Ce) provided an early Caledonian age (ca. 450 Ma) and younger population of ca. 410 ± 8 Ma. This age is consistent with previously reported 40Ar/39Ar cooling ages (410 ± 2 Ma) of muscovite supporting a retrograde growth of monazite. Petrochronological evidence combined with structural observations suggests that the Müllerneset Formation has been tectonically exhumed in the Early Devonian due to the NNW-SSE trending left-lateral shearing. Coeval folding and thrusting in the remaining basement of Oscar II Land to the east indicate a transpressional regime of the deformation in the Early Devonian. Similarly oriented contemporaneous tectonic zones within the Southwestern Basement Province of Svalbard may account for the same set of shear zones dispersing the Ordovician subduction complexes along western Spitsbergen.
      PubDate: Tue, 03 Jan 2023 00:00:00 GMT
       
  • Experimental immobilization of Zn, Pb and Cd by additives to highly
           contaminated soils

    • Abstract: The immobilization effect of soil amendments on leaching and bioavailability of Pb, Zn and Cd in highly contaminated soils under industrial impact was studied by collecting the soils in the surroundings of Zn-Pb Smelter “Miasteczko Śląskie” in southern Poland as an example. Various amounts of four additives (phosphate fertilizer, limestone powder, bentonite rock and bog iron ore) were tested in laboratory experiments to compare the effectiveness of three dominant mechanisms of immobilization: precipitation of phosphates, pH increase, and sorption. The contents of metals before immobilization were determined by extraction in CaCl2, EDTA and aqua regia. Cadmium and zinc are mainly represented by soluble, bio-available forms extractable in CaCl2, while lead by potentially bioavailable speciations extractable by EDTA. Most effective in the immobilization of these metals were the amendments increasing soil pH: limestone powder and phosphate fertilizer. Bog iron ore and bentonite were less effective because the soil pH was too low for efficient cation adsorption.
      PubDate: Sat, 24 Dec 2022 00:00:00 GMT
       
  • MinPlot: A mineral formula recalculation and plotting program for electron
           probe microanalysis

    • Abstract: MinPlot is a MATLAB®-based mineral formula recalculation and compositional plotting program for electron microprobe analyses (EPMA). The program offers recalculation and structural formula assignment for 15 different mineral groups: Garnet, pyroxene, olivine, amphibole, feldspar, mica, staurolite, cordierite, chlorite, chloritoid, talc, epidote, titanite, spinel, and sulfides. MinPlot is a fast and easy to use command line program and requires no prior computer programming knowledge. Percent mass fractions of oxides are loaded from datafiles and the user answers simple prompts to select mineral type, normalization scheme, and plotting options. Recalculated mineral formulas are automatically saved as output files and plots may be further manually customized by the user prior to saving. MinPlot can perform thousands of calculations in seconds and the modular nature of the program makes it simple to add new calculation routines in future releases. Combined, these features make MinPlot a powerful and useful program for the processing of EPMA data.
      PubDate: Thu, 15 Dec 2022 00:00:00 GMT
       
  • Health risk assessment in the vicinity of a copper smelter: particulate
           matter collected on a spider web

    • Abstract: We used spider webs as a particulate matter (PM) sampler to assess the possible health risk to the inhabitants of Legnica city (Poland). We aimed to find out if it is a useful material and could provide reliable information. We selected two spider families (Agelenidae and Linyphiidae) whose webs structure enhances the PM accumulation. The collected particles were analysed using a Scanning Electron Microscope equipped with Energy Dispersive X-Ray (SEM-EDX) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) which provided morphological and chemical information and allowed to indicate possible sources of pollution. The results showed that PM10, the fraction of particles smaller than 10 µm, was dominated by the particles of natural origin, while fine fractions were composed of diverse anthropogenic particles, whose origin can be connected with the activity of the copper smelter and in smaller quantity with the road traffic. The carcinogenic and non-carcinogenic health risk was assessed for these pathways: inhalation, ingestion, and dermal, for children and adults. The non-carcinogenic risk was very high (Hazard Index: HI > 1) both for children (Cu, Ni, Pb, Cd) and adults (Cu, As, Pb, Cd). Moreover, high carcinogenic risk (>10-4) was found in most of the sampling points. The study shows that spider webs are useful in biomonitoring of PM and can also be used for health risk assessment. In the studied region, it was found that the possible negative impact of air pollution on human health exists.
      PubDate: Fri, 09 Dec 2022 00:00:00 GMT
       
  • Mineralogical and geochemical evidence for two-stage silicification of
           serpentinized peridotites from the Szklary Massif (NE Bohemian Massif)

    • Abstract: Previously unknown exposures of silicified serpentinites have been documented within the Szklary Massif, which is a fragment of the tectonically dismembered Central Sudetic Ophiolite (NE Bohemian Massif). On the basis of textural, mineralogical and chemical differences, two types of silicified serpentinites have been distinguished in this study (Type I and Type II). Type I is characterized by well-preserved primary minerals cut by numerous veinlets filled with microscale euhedral quartz crystals. Studied samples of Type I are enriched in silica (from 62 to 69 wt.% SiO2) and depleted in magnesium (from 10 to 19 wt.% MgO) in comparison to serpentinized peridotites from the Szklary Massif. Type II is almost exclusively composed of amorphous or poorly crystalline silica, with microquartz aggregates being the most abundant form. Silicified serpentinites of Type II show extremely high values of silica (from 83 to 90 wt.% SiO2) and low magnesium concentrations (from 4 to 8 wt.% MgO). Both types of silicified serpentinites have elevated content of REE and many other trace elements generally regarded as incompatible. We infer that the earlier silicification event was caused by the percolation of Si-rich hydrothermal fluids derived from igneous rocks, which intruded this area from ca. 380 to 330 Ma. A subsequent silicification event is the result of silica remobilization during intense chemical weathering under tropical conditions, which could have occurred between Late Cretaceous and Miocene.
      PubDate: Wed, 15 Jun 2022 00:00:00 GMT
       
  • High temperature transformation of iron-bearing minerals in basalt:
           Mössbauer spectroscopy studies

    • Abstract: The high temperature decomposition of basalt from Lower Silesia (Poland) was followed by Mössbauer spectroscopy investigation. The Fe content of the sample was ~9.0 at.%. The X-ray diffraction analysis shows that augite (37%) and olivine (12%) are major Fe-bearing mineral components. The sample also contains significant amount of anorthite (22%) and nepheline (17%). The sample was heated at various temperatures between 200°C and 1100°C for three hours. Up to a temperature of 500°C changes in contribution of Fe-bearing minerals are insignificant. Heating in the temperature range from 500°C to 1100°C leads to a systematic increase in contribution of iron oxides at the cost of contribution of silicate minerals, like augite and olivine. Mössbauer spectrum obtained after heating at 1100°C showed hematite as the main iron oxide phase. The ratio of Fe3+/Fetot in the non-heated sample was equal to 0.51 and after heating at 1100°C this ratio amounted to 0.89.
      PubDate: Sat, 28 May 2022 00:00:00 GMT
       
  • New minerals and the first mineral occurrences in the Kupferschiefer (U,
           REE, HgS, chloride minerals PtAs, Pt(Sb,Bi), PtBi), Poland, and their
           genetic meaning

    • Abstract: Main U minerals in the Lubin and Polkowice mines in decreasing order of abundance are: uraninite, brannerite, metazunerite, metauranospinite, uranospinite, thucholite, monazite-huttonite, coffinite, and becquerelite. All these minerals are associated mainly with noble metal mineralization at the redox interfaces. Main minerals of REE are: (i) brannerite, monazite-huttonite in Noble Metals Bearing Shale (NMBS), (ii) florencite in Mo-Re shales and (iii) minor phospates in Cu-black shales derived from oxidation of organic matter. The latter, however, are controlling no more than 1/5 of the REE budget. Chloride minerals and sulphates are ubiquitous phases associated with Cu sulphides. They are represented by chlorargylite, cotunnite and penfieldite. Halite and sylvite form cubic inclusions in gypsum, up to 3 mm in chevrel compound, where they occur together with thiosulphates, anna-bergite and erithrite and Ni-Co-diarsenides. Sylvite is most common in lensoidal accumulations of semi massive kaolinite + chalcocite + gypsum at the contact between black shale and the top part of white sandstone. Such lenses have been traced over a distance of up to 30 m in the Lubin West and Polkowice East mines. Sylvite and halite have been so far overlooked during investigations of the Kupferschiefer because of applying standard cuƫng and polishing procedures using water as a lubricant. The Au content in native gold may reach exceptionally up to 97.40 wt% in a dolomitic reef from the Lubin West Mine. Gold forms four characteristic micro to nano-textures. Organic matrix of thucholite indicates correlation of Pt-Ni-V suggesting substitution of Pt in tetrapyrrole ring. Sperrylite, geversite and insizwaite appear at the western perimeter of Cu-sulphide deposit, where the redox gradient is so strong that almost all organic matter is gone. Platinum has forms its own minerals trapped in microfractures in anilite-digenite-spionkopite-yarrowite-bornite composite grains present in the reddened NMBS. Celestine-barite solid solution is one of the main accessory minerals in the Kupferschiefer. It has Sr/Ba ratio around 2.5 and 7.5. Euhedral uraninite associated with celestine-barite yielded U/Pb age of 84 ± 1 Ma, based on four grains measurements.
      PubDate: Sun, 27 Feb 2022 00:00:00 GMT
       
  • Developing teamwork skills in a course on ore deposits

    • Abstract: Teamwork has distinct pedagogic advantages and is also an important transferable skill and the dominant mode of work graduates encounter in the workplace. However, students rarely become proficient in teamwork skills during their education. The goal was to test strategies to improve teamwork skills in a course on Ores deposits, MSc Earth Science, Uppsala University. A focus on team-work was established by presenting the collaborative practicals as a series of linked opportunities to work together, get feedback on the teamwork process and reflect on and evaluate the teamwork. During the collaborative PBL sessions sociograms were used to provide feedback. Criteria based evaluation was also used to evaluate task oriented and interpersonal skills. Sociograms and criteria based evaluation promoted behavioural changes that improved teamwork interactions.
      PubDate: Fri, 18 Feb 2022 00:00:00 GMT
       
  • Mesoarchean melt and fluid inclusions in garnet from the Kangerlussuaq
           basement, Southeast Greenland

    • Abstract: The present work reports the first anatectic melt inclusions found so far in the Mesoarchean basement in East Greenland. Using optical microscope observations and MicroRaman spectroscopy, we show that garnets in metasedimentary migmatite contain primary polycrystalline aggregates which can be confidently interpreted as former droplets of anatectic melt, i.e. nanogranitoids. In some cases, they coexist with coeval fluid inclusions under conditions of primary fluid-melt immiscibility. The re-evaluation of the metamorphic pressure and temperature conditions with up-to-date phase equilibria modelling, combined with the identification of nanogranitoids and fluid inclusions, suggests metamorphic peak equilibration and partial melting in presence of a COH-fluid at T ~1000°C and P > 7 kbar. To date, this is the oldest verified occurrence of nanogranitoids and fluid-melt immiscibility during garnet growth in a partially molten environment.
      PubDate: Mon, 14 Feb 2022 00:00:00 GMT
       
 
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