Gold-galenite-sphalerite-chalcopyrite-pyrrhotite ores of the small Precambrian deposit Lobash-1 are located, together with the pyrite-molybdenite ore occurrences, within the zonal aureole of Lobash granite intrusion. The final formation of this ore deposit was substantially influenced by the Svecofennian processes. The Lobash intrusive complex is represented by the fluorine-bearing Na-K granites and leucogranites, which formation was accompanied by the hydrothermal-metasomatic alterations: albitization and greise-nization of the granites, propylitization and biotitization of the host rocks. The gold-sulfide veinlet mineralization occurs within zones of cataclasis foliation and biotitization at the contacts of dacite, rhyodacite and granodiorite-porphyry dikes, in the north-eastern part of the area. Besides the sulfide mineralization, the ores contain the native gold, electrum and bismuth, hessite, and various bismuthotellurides. The Au : Ag ratio in the ores makes 1 : 3-4. The ore mineralization and metasomatites were formed under decrease of temperature from 520 deg C (paragenesis of garnet amphibolites) down to 320-270 deg C (parage-nesis of pyrrhotite and pyrite, formation of sphalerite), and to 170-270 deg C (native gold, electrum). The molybdenum ores were formed over the apical part of intrusion, at T= 400-230 deg C (Pocalov, Semenova, 1993).
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