Electron Microprobe and Raman Spectroscopy Investigation of an Oxygen-Bearing Pt–Fe–Pd–Ni–Cu Compound from Nurali Chromitite (Southern Urals, Russia)

Abstract

AbstractOne grain, about 100×80μm in size, occurring in chromitite associated with the layered sequence of the Nurali mafic-ultramafic complex (Southern Urals, Russia) was investigated by electron-microprobe analyses and Raman spectroscopy. The grain is characterized by a spotty, rugged appearance and chemical zoning from which two compositions were calculated: (Pt0.35Pd0.26Fe0.22Cu0.01Ni0.05)0.98O1.02and (Fe0.90Pt0.58Ni0.28Pd0.13Cu0.08Rh0.01)1.98O1.02. In the lack of X-ray data, Raman spectroscopy established the presence of a diffuse 500–700 band and a sharp peak at 657 cm−1of relative wavenumber that strongly resemble the Raman spectra of synthetic PtO and PdO (palladinite). It is concluded that the Nurali grain probably represents a platinum group element (PGE) oxide, and does not consist of a mixture of PGE alloys with Fe oxide or hydroxide as reported for other natural PGE-O compounds.