Home – Home – Jornals – Geography and natural resources 2016 number 6S

Quartzites from Bural-Sardyk deposit are considered to be a source of high purity quartz raw material. The contents of fluid inclusions (FI) in quartzite is therefore an important technical characteristic. Fluid inclusions were studied in quartz grains of the most clean varieties of quartzites of the «productive series»: dark grey, grey and light grey fine-grained quartzites, and «superquartzites». The microcryothermometric parameters were measured using Linkam THMSG-600 thermal/freezing stage (Center for Isotopic-Geochemical Studies, IGC SB RAS, Irkutsk). The distribution of fluid inclusions in quartz grains is irregular. Cross fractures in quartz grains contain fluids, form band clusters with dense concentrations and narrow chains that intersect each other, extending in parallel or spaced apart. Two-phase fluid inclusions are observed at room temperature. Fluids that are flat tened, isometric, rounded and complex in shape are nor rare. The fluid inclusions differ in size in various types of quartzites, while the pattern of the distribution and phase composition are the same. It is practically impossible to measure microthermometric parameters in some fluid inclusions because of their minu te size (less than 8 microns). The temperature of ice melting was measured in fluid inclusions with a well-defined liquid phase. The analysis results showed that the salinity of fluid (from 5 to 9 wt.% NaCl-eq.) and its density increase from ultrapure «superquartz ites» to grey quartzites, with the FI sizes increasing in the same direction. It was established, that «superquartzites» are character ized by higher P-T-values of their formation conditions as compared to those of light gray and grey fine-grained quartzites.