Decoupling of Au and As during rapid pyrite crystallization

Geology ◽  
2021 ◽  
Author(s):  
Ya-Fei Wu ◽  
Katy Evans ◽  
Si-Yu Hu ◽  
Denis Fougerouse ◽  
Mei-Fu Zhou ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Secondary Ion Mass Spectrometry ◽  
Electron Backscatter Diffraction ◽  
Local Variation ◽  
Hydrothermal Systems ◽  
Central China ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Backscatter Diffraction

Gold (Au) is largely hosted by pyrite in a variety of hydrothermal systems, but the incorporation of Au into pyrite under disequilibrium conditions remains poorly understood. We integrate synchrotron X-ray fluorescence microscopy, electron backscatter diffraction, nanoscale secondary ion mass spectrometry, and laser ablation–multicollector–inductively coupled plasma–mass spectrometry to constrain the processes that sequester Au into zoned pyrite in the hydrothermal cement of breccia ores from the world-class Daqiao orogenic Au deposit, central China. Euhedral pyrite cores with oscillatory and sector zoning, variable δ34S values, and lower Au-As contents than the mantles are attributed to crystallization during oxidation of metal-depleted ore fluids with local variation in fluid conditions. The isotopically uniform colloform mantles are formed by pyrite crystallites separated by low-angle boundaries and are characterized by unusual decoupling of Au and As. Mantle formation is attributed to rapid disequilibrium precipitation from a metal-rich FeS2-supersaturated fluid. Incorporation of Au into the pyrite mantles was facilitated by abundant lattice defects produced by rapid nucleation. Gold-As–poor pyrite rims were deposited from an evolved ore fluid or other metal-depleted fluids. These results show that chemical variations recorded by fine layering within minerals can provide valuable insights into disequilibrium mass transfer and ore formation. The decoupling between Au and As in pyrite mantles indicates that As is not always a reliable proxy for Au enrichment in rapidly crystallized porous pyrite.

scholarly journals Further Characterization of the RW-1 Monazite: A New Working Reference Material for Oxygen and Neodymium Isotopic Microanalysis

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 583 ◽  
Author(s):  
Wu ◽  
Li ◽  
Ling ◽  
Yang ◽  
Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Reference Material ◽  
Inductively Coupled Plasma ◽  
Secondary Ion Mass Spectrometry ◽  
Hydrothermal Activity ◽  
Ionization Mass ◽  
Nd Isotopes ◽  
Inductively Coupled ◽  
The Matrix ◽  
Plasma Mass Spectrometry

The oxygen (O) and neodymium (Nd) isotopic composition of monazite provides an ideal tracer of metamorphism and hydrothermal activity. Calibration of the matrix effect and monitoring of the external precision of monazite O–Nd isotopes with microbeam techniques, such as secondary ion mass spectrometry (SIMS) and laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICPMS), require well-characterized natural monazite standards for precise microbeam measurements. However, the limited number of standards available is impeding the application of monazite O–Nd isotopes. Here, we report on the RW-1 monazite as a potential new working reference material for microbeam analysis of O–Nd isotopes. Microbeam measurements by electron probe microanalysis (EPMA), SIMS, and LA-MC-ICPMS at 10–24 µm scales have confirmed that it is homogeneous in both elemental and O–Nd isotopic compositions. SIMS measurements yield δ18O values consistent, within errors, with those obtained by laser fluorination techniques. Precise analyses of Nd isotope by thermal ionization mass spectrometry (TIMS) are consistent with mean results of LA-MC-ICPMS analyses. We recommend δ18O = 6.30‰ ± 0.16‰ (2SD) and 143Nd/144Nd = 0.512282 ± 0.000011 (2SD) as being the reference values for the RW-1 monazite.

Thermodynamically stabilized β-CsPbI3–based perovskite solar cells with efficiencies >18%

Science ◽  
2019 ◽  
Vol 365 (6453) ◽  
pp. 591-595 ◽  
Author(s):  
Yong Wang ◽  
M. Ibrahim Dar ◽  
Luis K. Ono ◽  
Taiyang Zhang ◽  
Miao Kan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Solar Cells ◽  
Inductively Coupled Plasma ◽  
Secondary Ion Mass Spectrometry ◽  
Spectral Response ◽  
Perovskite Solar Cells ◽  
Ambient Conditions ◽  
Perovskite Layer ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

Although β-CsPbI3 has a bandgap favorable for application in tandem solar cells, depositing and stabilizing β-CsPbI3 experimentally has remained a challenge. We obtained highly crystalline β-CsPbI3 films with an extended spectral response and enhanced phase stability. Synchrotron-based x-ray scattering revealed the presence of highly oriented β-CsPbI3 grains, and sensitive elemental analyses—including inductively coupled plasma mass spectrometry and time-of-flight secondary ion mass spectrometry—confirmed their all-inorganic composition. We further mitigated the effects of cracks and pinholes in the perovskite layer by surface treating with choline iodide, which increased the charge-carrier lifetime and improved the energy-level alignment between the β-CsPbI3 absorber layer and carrier-selective contacts. The perovskite solar cells made from the treated material have highly reproducible and stable efficiencies reaching 18.4% under 45 ± 5°C ambient conditions.

scholarly journals Quantitative electron microprobe mapping of otoliths suggests elemental incorporation is affected by organic matrices: implications for the interpretation of otolith chemistry

2016 ◽  
Vol 67 (7) ◽  
pp. 889 ◽  
Author(s):  
A. McFadden ◽  
B. Wade ◽  
C. Izzo ◽  
B. M. Gillanders ◽  
C. E. Lenehan ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Electron Backscatter Diffraction ◽  
Growth Patterns ◽  
Otolith Growth ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Organic Matrices ◽  
Plasma Mass Spectrometry ◽  
Minimal Damage ◽  
Backscatter Diffraction

In an effort to understand the mechanism of otolith elemental incorporation, the distribution of strontium (Sr) and sulfur (S) in otoliths of Platycephalus bassensis was investigated in conjunction with otolith growth patterns. Optimisation of electron probe microanalysis (EPMA) quantitative mapping achieved both high spatial resolution (<3µm) and two-dimensional visualisation of the fine scale Sr and S distributions in otoliths of P. bassensis with minimal damage. Electron backscatter diffraction (EBSD) mapping confirmed that grain growth is aligned with the otolith c-axis, with grain orientation independent of both otolith elemental composition and growth patterns. Results showed a linear correlation between Sr and S distribution (R2=0.86), and a clear association with the otolith growth patterns determined by scanning electron microscopy. Further examination by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) showed that incorporation of Mg and Ba appeared independent of both S distribution and the growth patterns. The results suggest that element incorporation into the otolith is linked to the organic composition in the endolymph during mineralisation, and the organic matrices may assist, in part, the uptake of Sr. Thus, these findings may have significant implications for the interpretation of otolith Sr chemistry.

Determination of anionic groups in wood by time-of-flight secondary ion mass spectrometry and laser ablation-inductively coupled plasma-mass spectrometry

Holzforschung ◽  
2010 ◽  
Vol 64 (1) ◽  
Author(s):  
Elena N. Tokareva ◽  
Andrey V. Pranovich ◽  
Paul Ek ◽  
Bjarne Holmbom
Keyword(s):  
Mass Spectrometry ◽  
Cell Walls ◽  
Inductively Coupled Plasma ◽  
Secondary Ion Mass Spectrometry ◽  
Alkaline Treatment ◽  
Inductively Coupled ◽  
Tof Sims ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Anionic Groups

Abstract A novel method for labelling of anionic groups on wood surfaces was developed and applied to spruce and aspen wood sections in the native state, and after acid washing and alkaline treatment. The metal ions Mg2+, Cu2+, Sr2+, and Zn2+ were used as markers and their patterns of attachment to anionic groups were assessed by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Sr2+ was found to be a very suitable marker for labelling of anionic groups. In addition to ToF-SIMS, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used for semi-quantitative analysis of labelled anionic groups in wood samples. ToF-SIMS imaging of Sr2+-labelled anionic groups revealed abundant anionic groups in bordered pit tori and ray parenchyma cell walls in spruce wood. LA-ICP-MS revealed that the relative concentration of Sr2+ in tori of bordered pits was approximately eight-fold higher than in fibre cell walls. After alkaline treatment the concentration of anionic groups in the fibre cell wall was approximately three-fold higher than in the original acid-washed spruce. In aspen wood, anionic groups were located mainly in pits between vessels and contact ray parenchyma cells, in ray cell walls and in certain fibre wall layers.

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