Fluid regime of platinum group elements (PGE) and gold-bearing reef formation in the Dovyren mafic-ultramafic layered complex, eastern Siberia, Russia

• Published in: Mineralium deposita 2000-08, Vol.35 (6), p.526-532
• Main Authors: Konnikov, E. G., Meurer, W. P., Neruchev, S. S., Prasolov, E. M., Kislov, E. V., Orsoev, D. A.
• Format: Article
• Language: English
• Subjects: Fluid dynamics; Gas chromatography; Geochemistry; Geophysics; Gold; Mineralization; Mineralogy; Nickel; Platinum; Reef formation; Spectrometry; Sulfides
• ISSN: 0026-4598; 1432-1866
• DOI: 10.1007/s001260050259

The Dovyren layered dunite-troctolite-gabbro massif (northern Transbaikalia region, Russia) contains precious metal mineralization related to sparsely disseminated sulfides (Stillwater type). The distribution of gases trapped in micro-inclusions and intergranular pores of the Dovyren massif has been investigated. This type of study had previously only been undertaken on the traps or peridotite-pyroxenite-norite intrusions hosting copper-nickel sulfide deposits. A novel method of analyzing trapped gases, involving the grinding of samples under high vacuum at room temperature, was employed. A modified gas-chromatography and mass-spectrometry approach was used to analyze the composition of the extracted gases. The concentrations of reduced gases (CH^sub 4^ and H^sub 2^) are higher in inclusions trapped by silicate minerals, whereas oxidized gases (H^sub 2^O, CO^sub 2^) are less common. The content of reduced gases (H^sub 2^, CH^sub 4^, CO), N^sub 2^, He, radiogenic Ar, and C^sub 2^H^sub 6^ increases upward through the layered series of the massif. The distribution of all gases, especially methane and hydrogen, show peak concentrations coincident with the PGE and gold reef type horizons. A correlation of the gas peaks and noble metal contents appears to be related to their geochemical affinities. This conclusion is supported by the experimental modeling.[PUBLICATION ABSTRACT]