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X-ray photoelectron spectroscopy and Raman microscopy of a ferroan platinum crystal from the Kondyor Massif, Russian Far East
摘要： X-ray Photoelectron Spectroscopy was used to study a ferroan platinum crystal from the Kondyor Massif, Russian Far East. Prior to the X-ray Photoelectron Spectroscopic analyses, the nature of the crystal was confirmed by X-ray diffraction. The survey scan showed mainly the presence of Pt and Fe, with smaller amounts of O and Si. The high resolutions spectra of the Pt 4f and Fe 2p showed 18.3 atom% Fe in the crystal, which puts the composition on the lower boundary for ferroan platinum and confirms earlier analyses using other methods such as Scanning Electron Microscopy-Energy Dispersive X-ray analysis/microprobe. The binding energy of the Pt 4f5/2 was 74.0 eV and Pt 4f7/2 70.5 eV, while the Fe 2p3/2 for metallic Fe was observed at 707.2 eV. The Fe 2p3/2 for metallic Fe was significantly sharper than that of Fe 2p3/2 at 710.7 eV associated with surface material. The Raman spectrum was dominated by the Pt–Pt stretching mode at 253 cm?1. Changed orientation resulted in the observation of two bands at 127 and 139 cm?1, interpreted as being due to stretching modes of two Pt–Pt bonds with the third bond to Fe and Pt fixed. The presence of Ca-Fe-Al-Mg-Si-O on the surface was probably associated with the presence of a clinopyroxene. These minerals can be expected since the crystal came originally from a clinopyroxenite-dunite matrix. The spectra showed a variety of interferences, e.g. Al 2p with Pt 4f, Mg 2p with Fe 3p, and Ca 2p1/2 with Mg Auger, making exact determinations of the ratios of these elements difficult.
关键词： surface chemistry,platinum group minerals,X-ray photoelectron spectroscopy,Raman spectroscopy,Platinum
更新于2025-09-23 15:23:52
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Micro-Raman Study of Thermal Transformations of Sulfide and Oxysalt Minerals Based on the Heat Induced by Laser
摘要： The minerals in the hydrothermal and cold seep system form at di?erent temperatures and show responses to the laser power to varying degrees. Here, we focus on the heat-induced by laser to study thermal transformations of the chalcopyrite, covellite, pyrite, barite, and aragonite based on Raman spectroscopy. Chalcopyrite mainly transforms into hematite, and covellite mainly transforms into chalcocite with the increase of laser power. Interestingly, comparing with the previous study, the pyrite can transform to the marcasite ?rstly, and form hematite ?nally. We also ?nd that high-temperature opaque chalcopyrite is more likely to occur thermal transformations due to the smaller absolute energy di?erence (|?E1|) based on the frontier orbital theory. In contrast, the oxysalt minerals won’t transform into new components under high laser power. However, the structure of the barite has been destroyed by the high laser power, while the more transparent aragonite is not a?ected by the high laser power due to the laser penetrates through the transparent aragonite crystal and causes little heat absorption. Finally, we established the minimum laser power densities for thermal transformations of these minerals formed under di?erent environments. The above study provides a simple way to study the thermal transformations of minerals by the local heat-induced by laser and also enlightens us to identify the minerals phases precisely.
关键词： Raman spectroscopy,laser,power densities,oxysalt,sul?de minerals,thermal transformations
更新于2025-09-23 15:19:57
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Comparative identification of citrus huanglongbing by analyzing leaves using laser-induced breakdown spectroscopy and near-infrared spectroscopy
摘要： In this work, laser-induced breakdown spectroscopy (LIBS), near-infrared spectroscopy (NIR), and LIBS joint NIR (LIBS–NIR) were investigated for the identification of citrus huanglongbing (HLB). The content of minerals like calcium (Ca), zinc (Zn), and potassium (K) was obtained by atomic absorption spectroscopy (AAS). The spectra of LIBS, NIR, and LIBS–NIR were operated by discriminating analysis (DA) and multi-layer perception (MLP). The results of AAS and Kolmogorov–Smirnov Test (K–S test) showed that the Ca and Zn decreased significantly in HLB infected leaves, but K is not significantly influence by HLB. The LIBS–NIR combining with MLP-PCA had highest diagnostic accuracy of 89.5% and 95.7% in training and test set, respectively. These results proved that joint spectrum of LIBS–NIR is a feasible method to identify citrus HLB.
关键词： laser-induced breakdown spectroscopy,minerals,identification,citrus huanglongbing,near-infrared spectroscopy
更新于2025-09-23 15:19:57
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Ge/Si Partitioning in Igneous Systems: Constraints From Laser Ablation ICP‐MS Measurements on Natural Samples
摘要： Mineral/melt and intermineral Ge/Si exchange coef?cients for nine common rock‐forming silicate minerals were determined by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA‐ICP‐MS). Ge/Si mineral/melt exchange coef?cients were found to vary by up to a factor of 10. In ma?c and ultrama?c systems, Ge/Si mineral/melt exchange coef?cients are less than 1 for plagioclase (0.48) and olivine (0.72), close to 1 for clinopyroxene (1.17) and orthopyroxene (1.07), and greater than 1 for garnet (2.69). In felsic and silicic systems, the Ge/Si mineral/melt exchange coef?cient is less than 1 for quartz (0.23), plagioclase (0.67), and potassium feldspar (0.67) but much greater than 1 for biotite (4.80) and hornblende (3.95). We show that early, olivine‐dominated fractionation of primitive basalts does not fractionate Ge/Si signi?cantly, but subsequent cotectic crystallization of plagioclase and pyroxene can increase the Ge/Si ratio from 6 × 10?6 to 7 × 10?6. We show that the only way to decrease Ge/Si during magmatic differentiation is by crystallization of hornblende or biotite (though biotite is typically a late crystallizing phase), consistent with hornblende being a major fractionating phase in hydrous intermediate magmas. The high compatibility of Ge in hornblende makes this element, in conjunction with Si, a potentially useful approach for distinguishing between hornblende and garnet in the source regions of intermediate magmas. The high compatibility of Ge in micas suggests that Ge/Si systematics may also be useful in understanding the origin of ultrapotassic magmas, which are often thought to derive from phlogopite‐rich sources.
关键词： igneous systems,magmatic differentiation,Ge/Si partitioning,rock‐forming silicate minerals,LA‐ICP‐MS
更新于2025-09-19 17:13:59
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In situ sequential U-Pb age and Sm-Nd systematics measurement of natural LREE-enriched minerals using single laser ablation multi-collector inductively coupled plasma mass spectrometry
摘要： In the present work, we describe a sequential U-Pb and Sm-Nd systematics measurement from natural LREE-enriched minerals by using a Neptune Plus MC-ICP-MS coupled with a 193nm excimer laser in a single shot. The MC-ICP-MS is equipped with zoom optics lens to bring ion beams into the collector coincidently. The key features allow rapid switching between U-Pb and Sm-Nd collector configuration, which is applied to simultaneously measure the U-Pb age and Sm-Nd isotope of common natural LREE-enriched minerals. The robustness and usefulness of the present protocol is investigated by using a series of well-characterized mineral reference materials (monazite, titanite, perovskite) with known U-Pb and Sm-Nd isotopic values, which demonstrate its potential and versatility in geochemistry and microanalysis for cosmochemistry.
关键词： U-Pb age,LREE-enriched minerals,Sm-Nd isotope,laser ablation,MC-ICP-MS
更新于2025-09-16 10:30:52
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UV-Vis spectroscopy
摘要： UV-Vis reflectance spectroscopy has been widely used as a non-invasive method for the study of cultural heritage materials for several decades. In particular, FORS, introduced in the 1980s, allows to acquire hundreds of reflectance spectra in situ in a short time, contributing to the identification of artist’s materials. More recently, microspectrofluorimetry has also been proposed as a powerful non-invasive method for the identification of dyes and lake pigments that provides high sensitivity and selectivity. In this chapter, the concepts behind these spectroscopic methodologies will be discussed, as well as the instrumentation and measurement modes used. Case studies related with different cultural heritage materials (paintings and manuscripts, textiles, carpets and tapestries, glass, metals, and minerals), which show the usefulness of UV-Vis reflectance spectroscopy and microspectrofluorimetry applied to the study of artworks, will also be presented.
关键词： glass,reflectance,microspectrofluorimetry,textiles,FORS,carpets and tapestries,paintings and manuscripts,minerals,non-invasive,metals,UV-Vis spectroscopy
更新于2025-09-10 09:29:36
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Bio-hydrometallurgy dynamics of copper sulfide-minerals probed by micro-FTIR mapping and Raman microspectroscopy
摘要： We report the μm-FTIR mapping and Raman microspectroscopic detection of bornite [Cu5FeS4]-, chalcocite [Cu2S]-, and covelitte [CuS]- bacterial interactions by a consortium of microorganisms consisted of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Acidithiobacillus caldus, Leptospirillum ferriphilum, Leptospirillum ferroodiazotrophum and Sulfobacillus thermosul?dooxidans. The absorption signals of amide I, K+-jarosite [KFe3(SO4)2(OH)6] and of the produced extracellular polymeric substances (EPS) from the mixed culture as a function of position on the surfaces of the bioleached bornite, chalcocite and covellite demonstrated their heterogeneity within the surface of the minerals. This reveals the high level of bio?lm, EPS, and jarosite biosynthesis on the surface of the minerals and might explain why they associate. To our knowledge this is the ?rst combined application of μm-FTIR mapping and Raman microspectroscopy for the bioleaching behaviour of bornite, chalcocite and covellite and the comparison with other bioleached systems such as chalcopyrite [CuFeS2] provides valuable information on the whole bio-hydrometallurgy Cu/Fe/S system. Both techniques provide spectrally rich, label-free, nondestructive visualizations of the bio-hydrometallurgy dynamics of copper sul?de minerals for processing and storage of large spectral data sets which are valuable for evaluation of copper containing minerals.
关键词： Micro-FTIR mapping,Copper sul?de minerals,Bio?lm formation,Jarosite biosynthesis,Raman
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Alteration Minerals Mapping Using MTMF and CEM Based on ASTER in Zedang Orefield of Tibet, China
摘要： Zedang copper polymetallic ore field, including several middle and large skarn-porphyry deposits for large metallogenic scale and special mineralized combination, locates in south rim of Eastern of Gangdise mountains in Tibet. Using the ASTER imagery and MTMF and CEM methods and field sample spectra, the alteration minerals of the Zedang ore field were mapped. From measuring the spectral of rock and mineral using SVC portable spectrograph, it derived consequence of exists some main alteration minerals. According to alteration minerals spectral feature, distribution map of alteration minerals is displayed using MTMF and CEM algorithm. Through compare analysis, it is considered that the CEM approach can suppress the background and extract more accuracy minerals than MTMF method in the high topographic relief area. The result is very important meaning for mineral prospecting.
关键词： Mineral Exploration,Zedang Orefield,Spectral Feature,Alteration Minerals,ASTER
更新于2025-09-04 15:30:14