Mineralization characteristics of platinum group elements in Jinchuan Cu-Ni-PGE deposit

摘要

1) In the cumulus stage, because of relatively low S content,PGE mainly appear as PGE ligands in sulfide liquid and silicate melting. When cumulus minerals such as olivine and chromite grow, a small amount of PGE ligands are in cumulus minerals.2) During the crystallized stage, the sulfide separated from silicate melting, and sulfide liquid dropped down to the bottom of the chamber with heavy specific gravity. The sulfide liquid set into the interstital space between cumulus minerals, and then the sulfide minerals crystallize from sulfide liquid. Some PGE ligands were trapped in sulfide minerals as a tiny inclusion. And some PGE reacted with S to enter into the sulfide lattice, Ru, Rh,Ir, and Os enter crystallized sulfide minerals when sulfide crystallized in early stage. For example, there may be relatively large amount of Os, Rh ortiny inclusions in pyrrhotite and pentlendite. With lower Dpdbetween monosulfide solid solution (mss) and sulfide liquid, Pd favors sulfide rather than mss. So Pd occurs as a substitute in pentlendite, a slightly late stage of crystallized minerals.