PGE geochemistry of carbonatites in Maoniuping REE deposit, Sichuan Province, China: Preliminary study

摘要

Concentrations of PGE and Au of seven carbonatite samples from the Maomuping REE deposit in China are reported (ppb): Ir 0.50similar to0.78, Ru 1.61similar to6.75, Rh 0.08similar to0.14, Pt 2.62similar to12.15, Pd 1.11similar to3.65 and Au 1.24similar to8.61, respectively. The primary mantle-normalized PGE distribution patterns reveal "swallow type" curve, with enrichment in Ru, Pt, Pd in comparison with Ir, Rh, and are similar to those of harzburgite in Dazhuka, Tibet, China. Nobles-metals reveal different trend with increase of Zr/Hf ratios. The preliminary study indicates that the overall PGE abundances of carbonatites are higher than the averages of MORB and OIB; the PGE of carbonatites underwent multi-source evolution. Fluids derived by metasomatism and subduction may transport PGE into carbonatite magmas. We suspect that besides the role of sulfides, volatile and alloys may modify PGE distribution patterns in carbonatite magma. [References: 56]