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Karagaikul gold-porhyric ore occurrence (South Urals): geochemistry and petrogenesis of intrusive rock, composition of minerals of near-ore metasomatites and ores

S.E. Znamensky, A.M. Kosarev, G.T. Shafigullina

Original article

DOI https://doi.org/10.18599/grs.2022.3.16

187-196
rus.

open access

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The petrological and geochemical characteristics of intrusive rocks, sources of magmatic melts, as well as the composition of minerals of near-ore metasomatites and ores of the Karagaikul gold-porphyry ore occurrence located in the Main Ural fault zone in the South Urals have been studied. The content of petrogenic oxides was determined by the silicate method, rare elements – using ICP-MS analysis on a quadrupole mass spectrometer ELAH 9000. The composition of minerals was studied using electron microscopic analysis on a scanning electron microscope REMMA-202M. It was found that gabbro, gabbro-diorite and diorite of the ore-bearing dyke series of the Karagaikul ore occurrence are suprasubduction magmatites of normal alkalinity belonging to the transitional and calc-alkaline petrogenetic series. They were formed from fluid-saturated melts. The main source of melts for intrusive rocks was most likely spinel peridotites of the suprasubduction lithospheric mantle, previously metasomatized by aquatic fluids that arose during the dehydration of rocks of the subducting oceanic plate. The dykes underwent propylitization of the biotite-actinolite facies in a near-ore halo (paragenesis: biotite + actinolite + epidote + orthoclase + albite + quartz + chlorite + pumpelliite), and the host serpentinized ultrabasites – carbonatization (chromogenesis: dolomite + magnesite). According to the chlorite geothermometer, the temperature of propylite formation is 287–317 °С. Sulfide minerals in gold-bearing stockworks are represented by pyrite, chalcopyrite, galena, pentlandite, pyrrhotine, and violarite.
 
South Urals, gold-porphyry mineralization, dykes, diorites, suprasubduction mantle, propylites
 
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Sergey E. Znamensky – Dr. Sci. (Geology and Mineralogy), Chief Researcher, Institute of Geology of the Ufa Federal Research Centre of the Russian Academy of Sciences 
16/2 K. Marx st., Ufa, 450077, Russian Federation
 
Alexandr M. Kosarev – Cand. Sci. (Geology and Mineralogy), Leading Researcher, Institute of Geology of the Ufa Federal Research Centre of the Russian Academy of Sciences
16/2, Karl Marx st., Ufa, 450077, Russian Federation
 
Gulnara T. Shafigullina – Cand. Sci. (Geology and Mineralogy), Senior Researcher, Institute of Geology of the Ufa Federal Research Centre of the Russian Academy of Sciences
16/2, Karl Marx st., Ufa, 450077, Russian Federation
 

For citation:

Znamensky S.E., Kosarev A.M., Shafigullina G.T. (2022). Karagaikul gold-porhyric ore occurrence (South Urals): geochemistry and petrogenesis of intrusive rock, composition of minerals of near-ore metasomatites and ores. Georesursy = Georesources, 24(3), pp. 187–196. DOI: https://doi.org/10.18599/grs.2022.3.16