Structural and chemical discontinuities in pyrite
Deditius, A.P., Kesler, S.E., Utsunomiya, S., Reich, M. and Ewing, R.C. (2011) Structural and chemical discontinuities in pyrite. In: 11th SGA Biennial Meeting on Let's Talk Ore Deposits, 26 - 29 September, Antofagasta, Chile pp. 258-260.
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Pyrite, FeS2, the most common sulfide mineral in ore deposits, exhibits trace-element rich growth zoning that reflects chemical and/or textural changes during its formation (e.g., Large et al., 2008; Barker et al., 2009; Deditius et al., 2009a). TEM data, coupled with EMPA analyses, allow identification and characterization of structural and chemical discontinuities between growth zones in pyrite at the nanoscale. EMPA analyses and SEM observations of pyrite from high-sulfidation epithermal deposits (Yanacocha and Pueblo Viejo) reveal that highest concentrations of trace elements (Au, Ag, As, Pb, Cu, Sb, Ni, Te) coincide with porous growth zones that vary in thickness from ̴50 nm to hundreds of micrometers. HRTEM and HAADF-STEM observations show that the growth zones consist of nanolayers containing homo- or heterogeneously distributed As and Cu in single crystals of pyrite or randomly distributed (As,Au,Pb)-rich aggregates of nanoparticulate pyrite, with individual grains ranging from 8 to 900 nm in size. �False� growth zoning is formed by densely distributed crystalline or amorphous non-pyrite phases.
|Publication Type:||Conference Paper|
|Publisher:||Society for Geology Applied to Mineral Deposits|
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