THE FORM OF RHENIUM OCCURRENCE IN MOLYBDENITE FROM DEPOSITS OF DIFFERENT GENETIC TYPES
Molybdenite is the basic rhenium-bearing mineral. This mineral was studied in samples taken from the porphyre-copper family, quartz-vein-greisen ore deposits, etc. To investigate forms of rhenium occurrence in the molybdenite crystal structure there were used back-scattered electron (BSE) and EPMA methods (Electron Probe Micro-Analyzer «Camebax-microbeam»). Molybdenite samples were studied with help of raster images. The plates of molybdenite were orientated perpendicular and parallel to the sample surface. The following X-ray bands were used as analytical: Mo L βl,S K α,Re L α, and M α; overlaps with other element bands were taken into account. Cu 3VS 4(for S), CaMoO 4 (for Mo) and pure metallic rhenium (for Re) were used as standards. The limit of the Re detection in molybdenite was 0.04 %. To study forms of the rhenium occurrence in molybdenites, different morphological varieties of this mineral were investigated from Erdenet (Mongolia) and «Cape Pavlovicha» (Magadan region) porphyry copper deposits, and Chikoysky (Transbaikalia) quarz-vein-greisen deposit. Data of the microprobe analysis allow to suppose that distribution of Re in molybdenite crystals is irregular and connected, probably, with presence of the 3R polytype molybdenite inclusions in matrix of molybdenite of the 2H polytype.