- © The Mineralogical Society Of America
In the sulfide mineral assemblages commonly found in terrestrial rocks, the major elements are S with the metals Fe, Zn, Cu, Pb, and Ag and semimetals As and Sb. Minor elements include Te, Se; the metals Ni, Cd, Co, Mn and the semimetals Hg and Bi. Particular ore deposits can be characterized using specific subsystems containing these elements (e.g., McKinstry 1963). Previous reviews have summarized in detail the phase relations in binary, ternary, and higher-order systems. These include Barton (1970), the first volume in this series (Craig and Scott 1976), excellent chapters by Barton and Skinner (1967, 1979), and Vaughan and Craig (1997) in Barnes’ valuable compendium, and particularly the comprehensive volume by Vaughan and Craig (1978, chapter 8). Characteristics of a few important subsystems are briefly presented here, but our emphasis is on new results since 1980, with an emphasis on equations of state suitable for computer-assisted calculation of phase relations applicable to terrestrial ore deposits, and generally to assemblages quenchable from natural systems. Most of these new results focus on the properties of sulfide mineral solutions and phase relations in portions of the supersystem Ag2S-Cu2S-ZnS-FeS-PbS-Sb2S3-As2S3-Bi2S3-Au-S2.
Solid solutions of a few minerals in this multisystem constitute a significant fraction of many hydrothermal ores, particular when they are initially deposited. Some of these solid solutions are not quenchable in phase (e.g., (Ag,Cu)2S solid solutions) or composition (e.g., PbS-AgSbS2-AgBiS2 galena solid solution), their instability with cooling giving rise to a multiplicity of more nearly stoichiometric sulfides and/or an exceeding diverse suite of modular sulfosalts (e.g., Skinner 1966; Hall and Czamanske 1972; Anthony et al. 1990; Makovicky 1997; see also in …