Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite

Minerals

Benjamin Wade¹  Aoife McFadden¹  ClaireE. Lenehan²  Allan Pring²  NigelJ. Cook³ 

[1] Adelaide Microscopy, The University of Adelaide, Adelaide 5005, South Australia, Australia;College of Science and Engineering, Flinders University, Adelaide 5001, South Australia, Australia;School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide 5005, South Australia, Australia;

关键词: wurtzite;    sphalerite;    trace element substitution;    animas;    merelani hills;   

DOI  :  10.3390/min10020147

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown