Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite
| Autor: | Claire E. Lenehan, Benjamin P. Wade, Allan Pring, Aoife McFadden, Nigel J. Cook |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
lcsh:Mineralogy lcsh:QE351-399.2 010504 meteorology & atmospheric sciences Base (chemistry) Chemistry Laser ablation inductively coupled plasma mass spectrometry Trace element Analytical chemistry Geology Electron microprobe engineering.material 010502 geochemistry & geophysics Geotechnical Engineering and Engineering Geology Epitaxy 01 natural sciences sphalerite animas trace element substitution Sphalerite wurtzite engineering merelani hills 0105 earth and related environmental sciences Wurtzite crystal structure |
| Zdroj: | Minerals, Vol 10, Iss 2, p 147 (2020) Minerals Volume 10 Issue 2 |
| Popis: | The nature of couple substitutions of minor and trace element chemistry of expitaxial intergrowths of wurtzite and sphalerite are reported. EPMA and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses display significant differences in the bulk chemistries of the two epitaxial intergrowth samples studied. The sample from the Animas-Chocaya Mine complex of Bolivia is Fe-rich with mean Fe levels of 4.8 wt% for wurztite-2H and 2.3 wt% for the sphalerite component, while the sample from Merelani Hills, Tanzania, is Mn-rich with mean Mn levels in wurztite-4H of 9.1 wt% and for the sphalerite component 7.9 wt% In both samples studied the wurtzite polytype is dominant over sphalerite. LA-ICP-MS line scans across the boundaries between the wurtzite and sphalerite domains within the two samples show significant variation in the trace element chemistries both between and within the two coexisting polytypes. In the Merelani Hills sample the Cu+ + Ga3+ = 2Zn2+ substitution holds across both the wurztite and sphalerite zones, but its levels range from around 1200 ppm of each of Cu and Ga to above 2000 ppm in the sphalerite region. The 2Ag+ + Sn4+ = 3Zn2+ coupled substitution does not occur in the material. In the Animas sample, the Cu+ + Ga3+ = 2Zn2+ substitution does not occur, but the 2(Ag,Cu)+ + Sn4+ = 3Zn2+ substitution holds across the sample despite the obvious growth zoning, although there is considerable variation in the Ag/Cu ratio, with Ag dominant over Cu at the base of the sample and Cu dominant at the top. The levels of 2(Ag,Cu)+ + Sn4+ = 3Zn2+ vary greatly across the sample from around 200 ppm to 8000 ppm Sn, but the higher values occur in the sphalerite bands. |
| Databáze: | OpenAIRE |
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