Crystal structural perfection and the associated properties of quartz as an indicator of vein vertical zoning: Example of the Verkhnealiinskoye gold deposit in Transbaikalia, Russia

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Research subject. A section of the V ore zone in the Verkhnealiinskoye gold deposit in Transbaikalia. Materials and methods. Samples of host rocks and ores from the core of exploratory wells, which cut the ore zone at depth intervals of 27–34; 57–104; 153–168; 285–293 m, were studied by the methods of chemical analysis, as well as determination of crystal structural perfection, phase α→β transition temperatures, and electrical resistivity of vein quartz. Results and conclusions. An increase in the degree of crystal structural perfection (CSP) of vein quartz in cross sections in the direction from the quartzification zone at the contacts to the axial parts of the vein from 59 to 73 (average 63) in the upper section, from 54 to 79 (average 67.2) in the lower-middle section, and from 86 to 93 (average 89.2) in the section below the wedging of the conductor was established. Over the entire depth range from 27 to 168 m, the average CSP value degree increases from 63 to 89.2. Similarly, although less clearly, phase (α→β) transition temperatures in quartz undergo changes; their connection with the CSP value was revealed. The electrical resistivity of vein quartz increases during the transition from the quartz zone to the quartz vein due to a decrease in the number of inclusions and impurities of hydromica and chlorite. The possibility of using the СSP value in combination with data on the content of gold, silver, and bismuth to assess the level of an erosion section of newly discovered gold manifestations is confirmed, both in individual undercuts by boreholes and in the form of dumps or bedrock outcrops of quartz veins.