Hasil untuk "Mineralogy"

Minge Liu, Yazhou Yang, Yang Liu et al.

The near-Earth asteroid Kamo`oalewa, a quasi-satellite of the Earth and the target for sample return by China's Tianwen-2 mission, exhibits distinctive spectral characteristics. This study re-analyzes the visible and near-infrared reflectance spectrum of Kamo`oalewa published by B. N. L. Sharkey et al. (2021), obtained using the Large Binocular Telescope, to infer its mineral composition and space weathering characteristics. Spectral similarity analysis is performed by comparing the spectrum of Kamo`oalewa to the mean spectra of various types in the Bus-DeMeo taxonomy to make a preliminary constraint on the combined characteristics of surface mineralogy and space weathering effects. To further characterize the mineral composition, a detailed analysis of the 1 μm band center is conducted based on spectral data below 1.25 μm that have higher signal-to-noise ratios. Empirical models for normalized spectra are developed to estimate the Is/FeO content. The results suggest that asteroid Kamo`oalewa has higher olivine abundance than that of typical S-type asteroids and the Moon, exhibiting an immature to submature degree of space weathering. These findings enhance our understanding of the evolution of similar quasi-satellites and provide important implication for the future exploration of Tianwen-2 mission.

David R. Rice, Chenliang Huang, Jason H. Steffen et al.

We use the TRAPPIST-1 system as a model observation of Earth-like planets. The densities of these planets being 1-10% less than the Earth suggest that the outer planets may host significant hydrospheres. We explore the uncertainty in water mass fraction from observed mass and radius. We investigate the interior structure of TRAPPIST-1 f using the open-source solver MAGRATHEA and varying assumptions in the interior model. We find that TRAPPIST-1 f likely has a water mass fraction of 16.2% $\pm$ 9.9% when considering all possible core mass fractions and requires 6.9% $\pm$ 2.0% water at an Earth-like mantle to core ratio. We quantify uncertainties from observational precision, model assumptions, and experimental and theoretical data on the bulk modulus of planet building materials. We show that observational uncertainties are smaller than model assumptions of mantle mineralogy and core composition but larger than hydrosphere, temperature, and equation of state assumptions/uncertainties. Our findings show that while precise mass and radius measurements are crucial, uncertainties in planetary models can often outweigh those from observations, emphasizing the importance of refining both theoretical models and experimental data to better understand exoplanet interiors.

Frédéric Galliano, Maarten Baes, Léo Belloir et al.

This paper develops a few science cases, using the PRIMA far-IR probe, aimed at achieving several breakthroughs in our understanding of the dust properties and their evolution. We argue that the specific observational capabilities of PRIMA, namely its unprecedented sensitivity over the whole far-IR range and the possibility to obtain continuous spectra between wavelengths 24 and 235 microns, are essential to progress in our understanding of the physics of the interstellar medium and galaxy evolution. Our science cases revolve around observations of nearby galaxies. We discuss the importance of detecting the IR emission of the diffuse interstellar medium of these galaxies, including very low-metallicity systems. We also discuss the opportunity of detecting various solid-state features to understand the mineralogy of interstellar grains. Finally, we stress the unique opportunity brought by the possible simultaneous measures of both the dust continuum and the far-IR fine-structure gas lines. These science cases could be distributed in a few large programs.

Kubilay Kaptan, Sandra Cunha, José Aguiar

Recycled powder (RP) is the primary by-product generated during the reclamation process of construction and demolition waste (CDW). There is existing literature on the use of RP as supplemental cementitious materials (SCMs) in cement-based materials, but a comprehensive evaluation on the characteristics of RP generated from concrete waste has been missing until now. This paper critically reviews the use of RP from concrete waste in cement-based materials, as concrete waste makes up a significant amount of CDW and other components have designated recycling methods. In this sense, this study conducted a critical analysis on the use of RP as an SCM, using detailed literature research. The technology used for producing RP is detailed along with its chemical, mineralogy, and microstructural characteristics. Fresh-state properties in cementitious matrices with RP are introduced with the view of mechanical grinding, thermal activation, carbonation, chemical treatment, biomineralization, mineral addition, nano activation, and carbonation. The review highlights the significant potential of utilizing RP in cement-based materials. Specifically, RP can be advantageously utilized in the production of value-added construction materials.

Michal Šujan, Kishan Aherwar, Rastislav Vojtko et al.

The data included in this article specify the characteristics of the Upper Miocene fill of the Turiec Basin and served for reconstruction of temporal evolution of depositional systems in this intermontane basin located within the Western Carpathians (Central Europe). The borehole lithological log data were used to describe the stratigraphy of the Turiec Basin in geological sections and were gained in the Geofond archive of the State Geological Institute of Dionýz Štúr. The sedimentological data were acquired by field research applying facies analysis to nine outcrop sites. The outcrops served for grain size analyzes performed by sieving and laser diffraction, for geochemical analyzes using ICP-ES, ICP-MS and XRF, and for mineralogical analyzes of whole rock and clay fraction by XRD. Moreover, the muddy layers on outcrops served for collection of 31 samples for the authigenic 10Be/9Be dating. The geochronological data are presented by using five different initial ratios for calculation, determined within the Turiec Basin at the Late Pleistocene alluvial fan and river terrace sites as well as at two Holocene muddy floodplain sites. Another initial ratio data are gained from an Upper Miocene lacustrine succession dated independently by magnetostratigraphy in previous research. Finally, a summary of previously published strontium isotope data from the Turiec Basin is included. The interpretations of the data are provided in Šujan et al., (2023) Palaeogeography, Palaeoclimatology, Palaeoecology 628, 111746.

Goryachev Andrey, Kompanchenko Alena, Potapov Sergey et al.

Processing of Allarechensk technogenic deposit (Murmansk region, Russia) by the low-temperature roasting method in mixture with ammonium sulfate was carried out in a laboratory scale. The ore was grinded to various size classes, mixed with ammonium sulfate and the mixture was roasted in a muffle furnace under a static air atmosphere, varying the roasting temperature from 300 to 500 °C, roasting duration from 60 to 300 minutes. The roasted mixture was leached in heated distilled water with constant stirring for 40 minutes. Using a particle size class of -40 microns, a raw material to reagent ratio of 1:7, after roasting at a temperature of 400 °C at the water leaching stage the metals recovery was: Ni 91.5%, Cu 94.8%. Copper was extracted from the pregnant solution by the method of cementation on iron, and nickel was extracted by adding brucite (Mg(OH)2) to the solution.

Mykhaylo Plotnykov, Diana Valencia

Determining compositions of low-mass exoplanets is essential in understanding their origins. The certainty by which masses and radius are measured affects our ability to discern planets that are rocky or volatile rich. In this study, we aim to determine sound observational strategies to avoid diminishing returns. We quantify how uncertainties in mass, radius and model assumptions propagate into errors in inferred compositions of rocky and water planets. For a target error in a planet's iron-mass fraction or water content, we calculate the corresponding required accuracies in radius and mass. For instance, a rocky planet with a known radius error of 2% (corresponding to TESS detection best errors) demands mass precision to be at 5-11% to attain a 8 wt% precision in iron-mass fraction, regardless of mass. Similarly, a water world of equal radius precision requires 9-20% mass precision to confine the water content within a 10 wt% margin. Lighter planets are more difficult to constrain, especially water-rich versus water-poor worlds. Studying Earth as an exoplanet, we find a $\sim \pm5$ point "error floor" in iron-mass fraction and $\sim \pm7$ in core-mass fraction from our lack of knowledge on mineralogy. The results presented here can quickly guide observing strategies to maximize insights into small exoplanet compositions while avoiding over-observing.

Giovanna Rizzo, Roberto Buccione, Marilena Dichicco et al.

A multi-analytical study on serpentinites in the ophiolite units (Calabria-Basilicata boundary, southern Apennines) was carried out on samples collected from a serpentinite quarry, locally called “Pietrapica”, which sitsin the Pollino UNESCO Global Geopark. Optical microscopy observations revealed the petrographic characteristics, ICP-MS was used to assess the chemical composition while EMPA mineral chemistry, Raman spectroscopy and X-Ray Powder Diffraction and were used altogether to trace the mineral composition of the rocks. Petrography revealed that serpentinites from Pietrapica quarry are essentially composed of serpentine group minerals, amphibole and carbonate minerals with lower abundances of talc and Cr-spinel. Raman spectroscopy and X-ray powder diffraction analysis clearly allowed to establish that carbonate minerals, serpentine and amphibole-like minerals, are the dominant phases, followed by 2:1 phyllosilicate. Electron probe microanalyses were carried out on different minerals in serpentinites samples including serpentine, amphibole, chlorite, clinopyroxene, magnetite, talc, quartz and titanite which are often associated with carbonate veins. Bulk geochemistry is dominated by major oxides SiO₂, MgO and Fe₂O₃ while the most abundant trace elements are Ni and Cr. Chemical analysis showed that some heavy metals in the studied serpentinites such as Ni and Cr, are beyond the maximum admissible limits for Italian normative for public, private and residential green as well as for commercial and industrial use representing a potential environmental concern. Anyway, some of these heavy metals have been recently listed by Europe as critical raw materials and therefore, the Pietrapica abandoned quarry could represent a new resource considering their economic potentiality.

Jiang Y., Kang J. T., Liao S. Y. et al.

The Chang'E 5 (CE-5) samples represent the youngest mare basalt ever known and provide an access into the late lunar evolution. Recent studies have revealed that CE-5 basalts are the most evolved lunar basalt, yet controversy remains over the nature of their mantle sources. Here we combine Fe and Mg isotope analyses with a comprehensive study of petrology and mineralogy on two CE-5 basalt clasts. These two clasts have a very low Mg# (~29) and show similar Mg isotope compositions with Apollo low-Ti mare basalts as well as intermediate TiO2 and Fe isotope compositions between low-Ti and high-Ti mare basalts. Fractional crystallization or evaporation during impact cannot produce such geochemical signatures which otherwise indicate a hybrid mantle source that incorporates both early- and late-stage lunar magma ocean (LMO) cumulates. Such a hybrid mantle source would be also compatible with the KREEP-like REE pattern of CE-5 basalts. Overall, our new Fe-Mg isotope data highlight the role of late LMO cumulate for the generation of young lunar volcanism.

R. V. Divya, G. Kumar, R. E. Cohen et al.

Germanates are often used as structural analogs of planetary silicates. We have explored the high-pressure phase relations in Mg$_2$GeO$_4$ using diamond anvil cell experiments combined with synchrotron x-ray diffraction and computations based on density functional theory. Upon room temperature compression, forsterite-type Mg$_2$GeO$_4$ remains stable up to 30 GPa. At higher pressures, a phase transition to a forsterite-III type (Cmc21) structure was observed, which remained stable to the peak pressure of 105 GPa. Using a 3rd order Birch Murnaghan fit to the experimental data, we obtained V0 = 305.1 (3) Å3, K0 = 124.6 (14) GPa and K0' = 3.86 (fixed) for forsterite- and V0 = 263.5 (15) Å3, K0 = 175 (7) GPa and K0' = 4.2 (fixed) for the forsterite-III type phase. The forsterite-III type structure was found to be metastable when compared to the stable assemblage of perovskite/post-perovskite + MgO, as observed during laser-heating experiments. Understanding the phase relations and physical properties of metastable phases is crucial for studying the mineralogy of impact sites, understanding metastable wedges in subducting slabs and interpreting the results of shock compression experiments.

Y. Fuchs, C. Fourdrin, E. Balan

<p>Density functional theory is used to investigate the vibrational stretching properties of OH groups in ideal and chemically disordered dravite models. Different schemes of cationic occupancy are considered, including the occurrence of vacancies at the X site and Mg–Al inversion between the Y and Z sites. The harmonic coupling between different OH groups is found to be smaller than 1 cm<span class="inline-formula">⁻¹</span>, indicating that the OH stretching dynamic in dravite can be described by considering a collection of nearly independent single OH oscillators. Their harmonic stretching frequency is linearly correlated with the corresponding OH bond length and most of the bands observed in the experimental vibrational spectra can be interpreted as consequences of the cationic occupancy of the sites coordinated to the OH group. The <span class="inline-formula">^V</span>(OH) and <span class="inline-formula">^W</span>(OH) stretching frequencies are affected by the Mg–Al inversion and by the presence of vacancies at the X site. In this last case, the frequencies depend on the isolated or more concentrated character of the X vacancy distribution along the <span class="inline-formula"><i>c</i></span> axis. Based on theoretical stretching frequencies, new interpretations are proposed for some of the bands experimentally observed in synthetic samples of dravite and magnesio-foitite.</p>

A. Morlok, C. Koike, K. Tomeoka et al.

Mid-infrared (5 micron to 25 micron) transmission/absorption spectra of differentiated meteorites (achondrites) were measured to permit comparison with astronomical observations of dust in different stages of evolution of young stellar objects. In contrast to primitive chondrites, achondrites underwent heavy metamorphism and/or extensive melting and represent more advanced stages of planetesimal evolution. Spectra were obtained from primitive achondrites (acapulcoite, winonaite, ureilite, and brachinite) and differentiated achondrites (eucrite, diogenite, aubrite, and mesosiderite silicates). The ureilite and brachinite show spectra dominated by olivine features, and the diogenite and aubrite by pyroxene features. The acapulcoite, winonaite, eucrite, and mesosiderite silicates exhibit more complex spectra, reflecting their multi-phase bulk mineralogy. Mixtures of spectra of the primitive achondrites and differentiated achondrites in various proportions show good similarities to the spectra of the few Myr old protoplanetary disks HD104237A and V410 Anon 13. A spectrum of the differentiated mesosiderite silicates is similar to the spectra of the mature debris disks HD172555 and HD165014. A mixture of spectra of the primitive ureilite and brachinite is similar to the spectrum of the debris disk HD113766. The results raise the possibility that materials produced in the early stage of planetesimal differentiation occur in the protoplanetary and debris disks.

Ye Huang, Ye Huang, Xiu-Tong Li et al.

The microbial community of acid mine drainage (AMD) fascinates researchers by their adaption and roles in shaping the environment. Molecular surveys have recently helped to enhance the understanding of the distribution, adaption strategy, and ecological function of microbial communities in extreme AMD environments. However, the interactions between the environment and microbial community of extremely acidic AMD (pH &lt;3) from different mining areas kept unanswered questions. Here, we measured physicochemical parameters and profiled the microbial community of AMD collected from four mining areas with different mineral types to provide a better understanding of biogeochemical processes within the extremely acidic water environment. The prominent physicochemical differences across the four mining areas were in SO42−, metal ions, and temperature, and distinct microbial diversity and community assemblages were also discovered in these areas. Mg2+ and SO42− were the predominant factors determining the microbial structure and prevalence of dominant taxa in AMD. Leptospirillum, Ferroplasma, and Acidithiobacillus were abundant but showed different occurrence patterns in AMD from different mining areas. More diverse communities and functional redundancy were identified in AMD of polymetallic mining areas compared with AMD of copper mining areas. Functional prediction revealed iron, sulfur, nitrogen, and carbon metabolisms driven by microorganisms were significantly correlated with Mg2+ and SO42−, Ca2+, temperature, and Fe2+, which distinguish microbial communities of copper mine AMD from that of polymetallic mine AMD. In summary, microbial diversity, composition, and metabolic potential were mainly shaped by Mg2+ and SO42− concentrations of AMD, suggesting that the substrate concentrations may contribute to the distinct microbiological profiles of AMD from different mining areas. These findings highlight the microbial community structure in extremely acidic AMD forming by types of minerals and the interactions of physicochemical parameters and microbiology, providing more clues of the microbial ecological function and adaptation mechanisms in the extremely acidic environment.

H. E. Belkin, R. Macdonald, R. Macdonald

<p>The mineral occurrences, parageneses, textures, and compositions of Zr-bearing accessory minerals in a suite of UK Paleogene granites from Scotland and Northern Ireland are described. Baddeleyite, zirconolite, and zircon, in that sequence, formed in hornblende <span class="inline-formula">+</span> biotite granites (type 1) and hedenbergite–fayalite granites (type 2). The peralkaline microgranite (type 3) of Ailsa Craig contains zircon, dalyite, a eudialyte-group mineral, a fibrous phase which is possibly lemoynite, and Zr-bearing aegirine. Hydrothermal zircon is also present in all three granite types and documents the transition from a silicate-melt environment to an incompatible element-rich aqueous-dominated fluid. No textures indicative of inherited zircon were observed. The minerals crystallized in stages from magmatic through late-magmatic to hydrothermal. The zirconolite and eudialyte-group mineral are notably Y<span class="inline-formula">+</span>REE-rich (REE signifies rare earth element). The crystallization sequence of the minerals may have been related to the activities of Si and Ca, to melt peralkalinity, and to local disequilibrium.</p>

Mariana I. Rakhmanova, Andrey Yu. Komarovskikh, Yuri N. Palyanov et al.

For this study, 21 samples of colorless octahedral diamonds (weighing 5.4–55.0 mg) from the Mir pipe (Yakutia) were investigated with photoluminescence (PL), infrared (IR), and electron paramagnetic resonance (EPR) spectroscopies. Based on the IR data, three groups of diamonds belonging to types IIa, IaAB, and IaB were selected and their spectroscopic features were analyzed in detail. The three categories of stones exhibited different characteristic PL systems. The type IaB diamonds demonstrated dominating nitrogen–nickel complexes S2, S3, and 523 nm, while they were less intensive or even absent in the type IaAB crystals. The type IIa diamonds showed a double peak at 417.4 + 418.7 nm (the 418 center in this study), which is assumed to be a nickel–boron defect. In the crystals analyzed, no matter which type, 490.7, 563.5, 613, and 676.3 nm systems of various intensity could be detected; moreover, N3, H3, and H4 centers were very common. The step-by-step annealing experiments were performed in the temperature range of 600–1700 °C. The treatment at 600 °C resulted in the 563.5 nm system’s disappearance; the interstitial carbon vacancy annihilation could be considered as a reason. The 676.5 nm and 613 nm defects annealed out at 1500 °C and 1700 °C, respectively. Furthermore, as a result of annealing at 1500 °C, the 558.5 and 576 nm centers characteristic of superdeep diamonds from São Luis (Brazil) appeared. These transformations could be explained by nitrogen diffusion or interaction with the dislocations and/or vacancies produced.

Dmitrii A. Ganyushkin, Sofia N. Lessovaia, Dmitrii Y. Vlasov et al.

For the Altai Mountains’ region, especially the arid southeastern part of the Russian Altai, the data on glacier fluctuations in the Pleistocene and Holocene are still inconsistent. The study area was the Kargy River’s valley (2288–2387 m a.s.l.), a location that is not currently affected by glaciation and the glacial history of which is poorly studied. Field observations and geomorphological mapping were used to reveal the configuration of Pleistocene moraines. The relative dating method was applied to define the degree of weathering as an indicator of age. Three moraine groups of different ages (presumably MIS 6, MIS 4, and MIS 2) were identified based on a detailed investigation of their morphological features and the use of relative dating approaches. The latter were primarily based on weathering patterns. Data on the rock mineralogy, porosity, and specificity of biological colonization as an agent of weathering were obtained for the moraine debris. The studied moraines were composed of fine-grained schist, in which the specific surface area and fractality (self-similarity) were more developed in the older moraine. The growth of biota (crustose lichen and micromycetes) colonizing the rock surface led to rock disintegration and the accumulation of autochthonous fragments on the rock surface. Despite the fact that the initial stage(s) of moraine weathering affected by biota was fixed, the correlation trends of biota activity and moraine ages were not determined.

Zoltan Vaci, Carl B. Agee, Munir Humayun et al.

Northwest Africa (NWA) 11042 is a heavily shocked achondrite with medium-grained cumulate textures. Its olivine and pyroxene compositions, oxygen isotopic composition, and chromium isotopic composition are consistent with L chondrites. Sm-Nd dating of its primary phases shows a crystallization age of 4100 +/- 160 Ma. Ar-Ar dating of its shocked mineral maskelynite reveals an age of 484.0 +/- 1.5 Ma. This age coincides roughly with the breakup event of the L chondrite parent body evident in the shock ages of many L chondrites and the terrestrial record of fossil L chondritic chromite. NWA 11042 shows large depletions in siderophile elements (<0.01 times CI) suggestive of a complex igneous history involving extraction of a Fe-Ni-S liquid on the L chondrite parent body. Due to its relatively young crystallization age, the heat source for such an igneous process is most likely impact. Because its mineralogy, petrology, and O isotopes are similar to the ungrouped achondrite NWA 4284 (this work), the two meteorites are likely paired and derived from the same parent body.

Gabriel Nzulu, Per Eklund, Martin Magnuson

Gold-associated pathfinder minerals have been investigated by identifying host minerals of Au for samples collected from an artisanal mining site near a potential gold mine (Kubi Gold Project) in Dunkwa-On-Offin in the central region of Ghana. We find that for each composition of Au powder (impure) and the residual black hematite/magnetite sand that remains after gold panning, there is a unique set of associated diverse indicator minerals. These indicator minerals are identified as SiO2 (quartz), Fe3O4 (magnetite), and Fe2O3 (hematite), while contributions from pyrite, arsenopyrites, iridosmine, scheelite, tetradymite, garnet, gypsum, and other sulfate materials are insignificant. This constitutes a confirmative identification of Au pathfinding minerals in this particular mineralogical area. The findings suggest that X-ray diffraction could also be applied in other mineralogical sites to aid in identifying indicator minerals of Au and the location of ore bodies at reduced environmental and exploration costs.

B-G Andersson, Geoffrey C. Clayton, Kirstin D. Doney et al.

Continuum polarization over the UV-to-microwave range is due to dichroic extinction (or emission) by asymmetric, aligned dust grains. Because of both grain alignment and scattering physics, the wavelength dependence of the polarization, generally, traces the size of the aligned grains. Ultraviolet (UV) polarimetry therefore provides a unique probe of the smallest dust grains (diameter$<0.09μ$m), their mineralogy and interaction with the environment. However, the current observational status of interstellar UV polarization is very poor with less than 30 lines of sight probed. With the modern, quantitative and well-tested, theory of interstellar grain alignment now available, we have the opportunity to advance the understanding of the interstellar medium by executing a systematic study of the UV polarization in the ISM of the Milky Way and near-by galaxies. The Polstar mission will provide the sensitivity and observing time needed to carry out such a program, addressing questions of dust composition as a function of size and location, radiation- and magnetic-field characteristics as well as unveiling the carrier of the 2175Å extinction feature. In addition, using high-resolution UV line spectroscopy Polstar will search for and probe the alignment of, and polarization from, aligned atoms and ions - so called "Ground State Alignment", a potentially powerful new probe of magnetic fields in the diffuse ISM.

Keith D. Putirka, Siyi Xu

Prior studies have hypothesized that some polluted white dwarfs record continent-like granitic crust--which is abundant on Earth and perhaps uniquely indicative of plate tectonics. But these inferences derive from only a few elements, none of which define rock type. We thus present the first estimates of rock types on exoplanets that once orbited polluted white dwarfs--stars whose atmospheric compositions record the infall of formerly orbiting planetary objects--examining cases where Mg, Si, Ca and Fe are measured with precision. We find no evidence for continental crust, or other crust types, even after correcting for core formation. However, the silicate mantles of such exoplanets are discernible: one case is Earth like, but most are exotic in composition and mineralogy. Because these exoplanets exceed the compositional spread of >4,000 nearby main sequence stars, their unique silicate compositions are unlikely to reflect variations in parent star compositions. Instead, polluted white dwarfs reveal greater planetary variety in our solar neighborhood than currently appreciated, with consequently unique planetary accretion and differentiation paths that have no direct counterparts in our Solar System. These require new rock classification schemes, for quartz + orthopyroxene and periclase + olivine assemblages, which are proposed here.