GEOCHEMISTRY, MINERALOGY AND SOURCES OF MATTER OF QUARTZ VEINS AND QUARTZITES, SOUTH BORSHCHOVOCHNY RIDGE (TRANSBAIKALIA)
A.M. Fedorov 1, G.A. Yurgenson 2, A.I., Nepomnyashchikh 1, A.P. Zhaboedov 1, M.D. Zimin 1, Z.I. Kulikova 1, V.A. Makrygina 1, O.I. Chachanagova 1, D.TS. Aurzhanaeva
1A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia.
2Institute of Natural Resources, Ecology and Cryology, Siberian Branch of the Russian Academy of Sciences, Chita, Russia.
3 N.L. Dobretsov Geological Institute, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Russia
Keywords: Transbaikalia, Borshchovichny Ridge, quartz veins, quartzites, geochemistry, fluid inclusions, oxygen isotopes
Abstract
Quartz veins and quartzites of the Unda quartz vein zone (southern part of the Borshchovochny Ridge) of the Argun block of the Mongol-Okhotsk fold belt have been studied using modern high-precision methods. The first detailed characteristics of mineralogical, petrographic and geochemical features of quartz of the Unda zone is given. Samples of vein quartz and quartzites taken at the tectonic contact between the igneous Middle-Late Jurassic granitoids of the Borshchovoсhny complex and overlying volcanogenic-sedimentary rocks of the accretionary complex of the Middle Jurassic age (Talangui Formation) are intensely deformed and mylonitized. Another part of quartz veins formed in metamorphic rocks located at a distance from the tectonized zone (Dzhidinsky section) are weakly granulated. The parameters of fluid inclusions in vein quartz in the Borshchovochny and Talangui sections were determined. Quartz veins and quartzites are genetically related to the host rocks and inherit their geochemical and isotopic features. As a result of deformation processes, the content and ratio of impurity elements in quartz veins and quartzites decreases and changes.
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