| Popis: |
The Kharaelakh intrusion is one of several sill-like, multiphase gabbroic intrusions that host world-class Ni-Cu-PGE deposits in the Noril’sk-Talnakh region. The sulfide ores of the Kharaelakh intrusion are characterized by elevated δ34S values (10–12‰) and high PGE concentrations (e.g., up to10 ppm Pt). The δ34S values require addition of crustal S with elevated isotope ratios such as evaporite-bearing country rocks (δ34S, ~20‰) and R factors (magma/sulfide mass ratios) of 2,000) if Pt content in the magma is similar to the values in the coeval, most undepleted lavas (~10 ppb). Such a discrepancy can be explained by sulfide resorption by a new flux of mantle-derived magma into a deep staging chamber to form PGE-enriched magma. Interaction of the PGE-enriched magma with evaporite-bearing country rocks in the plumbing system at higher crustal levels could have produced sulfide liquids with high PGE contents as well as elevated δ34S values. Mass-balance calculations indicate that |
