Svaneti Gold Occurence (Kirar-Abakuri Ore Knot) and its Genesis

摘要

There is a potential opportunity of gold deposits discovery on the territory of Georgia, and first of all, along Svaneti ridge, at its western part within the Kirar-Abakuri ore knot. Here are known ore occurrences, which by geological, mineralogical and geochemical features belong to gold-quartz-low sulfide deposits. The article includes 1:50 000 scale geological maps of lukbra potential gold deposit and Kirar-Abakuri ore knot, and geological and mineralogical features of the deposit structure are taken into consideration. Here, at endocontact zone of the Middle Jurassic montsodiorite gold-bearing quartz veins are located. Montsodiorite crosses sedimentary rock of so-called "Dizi series" that experienced regional metamorphism of the greenschist facies. Sedimentary rocks are characterized by strong disturbance, milonitization and folding. The quartz-sericite-chlorite metasomatites and sulfide disseminations in sedimentary rocks are also observed. Directly in the contact zone of the Lukhra intrusion and the Dizi series quartz-biotite and quartz-biotite-andalusite association metasomatites are defined. In the apical part of the Lukhra intrusion three gold-bearing zones are revealed, gold content in one of them (the main zone with thickness of 14 m) varies within 8.89 - 7.48 g/t. The genetic conditions of Lukhra potential deposit formation are discussed in the paper. According to the authors, gold distribution, and concentration in pore waters and sulfide minerals took place at metagenesis stage. Further, under the influence of the mantle plumes (apparently montsodiorites are derivates of plumes), gold-bearing environment was developed as magmatic system. Magmatic melt saturated by fluid moves to the upper levels of the Earth's crust, where as a result of the pressure and temperature drop the vapor-gaseous mobilizate emissions. As a result of interaction of the mobilizate and metamorphogenic waters hydrosystem evolve. Over the time, it seems, in the Midlle-Upper Jurassic, flint-containing gel and sulfides discharged from the hydro system.