Chemical and Os-Isotopic Composition of Ru–Os Sulfides from the Verkh-Neivinsky Dunite-Harzburgite Massif (Middle Urals, Russia)

Resumo

This study presents new chemical and isotope data for Ru–Os sulfides and coexisting platinum-group minerals (PGMs) within primary assemblage derived from the Verkh-Neivinsky dunite-harzburgite massif. PGMs were studied using electron microprobe analysis, laser ablation and multiple collector-inductively coupled plasma-mass spectrometry. The obtained results are consistent with: (i) high-temperature formation of Ru–Os sulfides and coexisting Os-bearing alloys, (ii) presence of two contrasting sources in the ore formation (i.e., subchondritic and suprachondritic), (iii) resemblance of the initial Os-isotope composition in coexisting laurite and Os-bearing alloy, (iv) significant Os-isotope variations in individual PGMs from the primary assemblage, and (v) potential of using model ¹⁸⁷Os/¹⁸⁸Os ages of PGMs for geodynamic paleoreconstructions.