Fractional crystallization of monosulfide solid solution from sulfide liquids lead to the PGE enrichment in the Jinchuan Ni-Cu sulfide deposit, western China
Discordant lenses of Pt-Pd enriched zones (ores bearing
up to 1.0 ppm of Pt or Pd) have recently been identified in the
sulfide-bearing peridotite of the Jinchuan Cu-Ni-PGE
(Platinum group element) sulfide deposit, China.
Chalcopyrite, pyrrhotite, and pentlandite occur in both Pt-Pd
enriched zones and normal ores, but Cu-bearing minerals
such as cubanite and Bi-, Te-, and As-bearing minerals are
more abundant in the Pt-Pd enriched zones. Sperrylite is the
major Pt-host minerals in the Pt-Pd enriched zones
interstinally and occurs mainly as euhedral grains within
base-metal sulfides which occur among the cumulates of
olivine. PGE-enrichment is found only in sulfide-bearing
samples. In orebody # 1 and orebody 24, Rh, Ru, and Ir are
positively correlated, but a negative Ir-Pd and Ir-Pt
correlation. However in orebody 2 Rh, Ru, Pt, Pd and Ir are
positively correlated.
Taken together, the elemental correlations and
mineralogical data support a model for the origin of Pt-Pd
rich ores in Orebody 1 and Orebody 24 of the Jinchuan
deposit are consistent with fractional crystallization of
monosulfide solid solution from sulfide liquids on cooling;
The origin of Orebody 2 involves variable magma/sulfide
liquid mass ratios (R-factors).published_or_final_versio