PETROLOGY OF MAFIC-ULTRAMAFIC KIZIR-BURLUKSKY MASSIF (NORTHEAST OF WESTERN SAYAN)

Abstract

The relevance of the research. Numerous intrusive mafic-ultramafic bodies have been established in the Western Sayan. Their formational affiliation and metallogenic specialization have not yet been fully clarified and constantly attract attention of both industrial and scientific organizations in relation to their metallogenic specialization in chromium, nickel, copper, and precious metals. To clarify their formation affiliation, we obtained the original results of a petrological study of the mafic-ultramafic Kizir-Burluksky massif, which allow us to identify the conditions for its formation, subsequent transformation during long-term evolution at the upper mantle – earth crust levels. Objects: mafic-ultramafic Kizir-Burluksky massif. It is located in the north-eastern part of the Western Sayan and, together with the Kalninsky and Ergaksky massifs, is an integral part of the potentially chromite-bearing massifs of the Amylsky ore region. Methods. Petrographic studies of ultramafic rocks were carried out with polarizing microscope AxioScope-40 Carl Zeiss. The chemical composition of silicate and ore minerals was determined by the method of X-ray spectrum microanalysis using a scanning electron microscope Tescan Vega II LMU equipped with an energy-dispersive spectrometer Oxford INCA Energy 350 and a wave-dispersive spectrometer Oxford INCA Wave 700. Results. According to a petrological study, the Kizir-Burluksky massif is represented mainly by extremely depleted dunites, formed in the upper mantle, at the levels of which they underwent intense high-temperature plastic deformations by intracrystalline translational slip with a subordinate role of syntectonic recrystallization. In crustal conditions, under the influence of later of gabbroid intrusives, the dunites underwent a high-temperature metasomatism with the formation of rocks of the verlite-clinopyroxenite association.

Keywords

• western sayan
• ophiolites
• ultramafic rocks
• dunite
• gabbroides
• petrography
• mineralogy