MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)

The paper examines mineralogy of noble metals and ore formation conditions at the Naily gold deposit (South Urals), which is hosted in pyrite-bearing talc-carbonate, chlorite-quartz-carbonate and quartz-carbonate metasomatites after serpentinites and rocks of a gabbrodiorite-plagiogranite complex. B...

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Main Authors: A.D. Smirnitskaya, E.A. Rozhkova, E.V. Belogub, K.A. Novoselov, M.V. Zabotina, M.A. Rassomakhin
Format: Article
Language:English
Published: South Urals Federal Research Center of Mineralogy and Geoecology UB RAS 2024-12-01
Series:Минералогия
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Online Access:https://journal.mineralogy.ru/wp-content/uploads/2025/01/2024_10_4_7.pdf
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author A.D. Smirnitskaya
E.A. Rozhkova
E.V. Belogub
K.A. Novoselov
M.V. Zabotina
M.A. Rassomakhin
author_facet A.D. Smirnitskaya
E.A. Rozhkova
E.V. Belogub
K.A. Novoselov
M.V. Zabotina
M.A. Rassomakhin
author_sort A.D. Smirnitskaya
collection DOAJ
description The paper examines mineralogy of noble metals and ore formation conditions at the Naily gold deposit (South Urals), which is hosted in pyrite-bearing talc-carbonate, chlorite-quartz-carbonate and quartz-carbonate metasomatites after serpentinites and rocks of a gabbrodiorite-plagiogranite complex. Based on microscopic and electron microscopic studies of polished sections and heavy concentrates, it is established that native gold and Au tellurides are the major Au minerals of veins, metasomatites after intermediate and felsic intrusive rocks and foliated serpentinites. Native gold occurs as: 1) inclusions in pyrite and rarely in chalcopyrite, 2) free particles associated with non-metallic minerals, which probably fill interstitions, 3) interstitial forms in pyrite aggregates often together with chalcopyrite, galena and sphalerite, and veinlets in hessite, 4) fine inclusions in tetradymite and 5) inclusions in limonite. Tellurides of noble metals include calaverite, petzite, hessite and an unidentified Ag and Pb sulfotelluride. Silver is also incorporated in acanthite and Hg-Ag-Sb-As, Pb-Bi-Ag and Cu-Ag-Pb-Bi sulfosalts. The Ag content of free native gold is 10–16 wt. % increasing to 20–24 wt. % in native gold in pyrite and in assemblage with hessite. Altaite, coloradoite and Ni and Pd tellurides are found in assemblages similar to noble metal mineralization. The formation temperature of chlorite from ore-bearing metasomatites is 339–392 °C. Fluid inclusions in quartz, calcite and albite are homogenized at a temperature range of 162–377 °C. The eutectic temperature (–23.5 °C) is typical of NaClKCl-H2O system. The ice melting temperature varies from –0.5 to –3.7 °C corresponding to salinity of 0.9– 6.0 wt. % NaCl-equiv.
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id doaj-art-6b8ff945da8e4343b7746319acb301a3
institution Kabale University
issn 2313-545X
2782-2044
language English
publishDate 2024-12-01
publisher South Urals Federal Research Center of Mineralogy and Geoecology UB RAS
record_format Article
series Минералогия
spelling doaj-art-6b8ff945da8e4343b7746319acb301a32025-02-06T10:44:08ZengSouth Urals Federal Research Center of Mineralogy and Geoecology UB RASМинералогия2313-545X2782-20442024-12-0110415017110.35597/2313-545X-2024-10-4-7MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)A.D. Smirnitskaya0E.A. Rozhkova1E.V. Belogub2K.A. Novoselov3M.V. Zabotina4M.A. Rassomakhin5South Urals Federal Research Center of Mineralogy and Geoecology UB RASSouth Urals Federal Research Center of Mineralogy and Geoecology UB RASSouth Urals Federal Research Center of Mineralogy and Geoecology UB RASSouth Urals Federal Research Center of Mineralogy and Geoecology UB RASSouth Urals Federal Research Center of Mineralogy and Geoecology UB RASSouth Urals Federal Research Center of Mineralogy and Geoecology UB RASThe paper examines mineralogy of noble metals and ore formation conditions at the Naily gold deposit (South Urals), which is hosted in pyrite-bearing talc-carbonate, chlorite-quartz-carbonate and quartz-carbonate metasomatites after serpentinites and rocks of a gabbrodiorite-plagiogranite complex. Based on microscopic and electron microscopic studies of polished sections and heavy concentrates, it is established that native gold and Au tellurides are the major Au minerals of veins, metasomatites after intermediate and felsic intrusive rocks and foliated serpentinites. Native gold occurs as: 1) inclusions in pyrite and rarely in chalcopyrite, 2) free particles associated with non-metallic minerals, which probably fill interstitions, 3) interstitial forms in pyrite aggregates often together with chalcopyrite, galena and sphalerite, and veinlets in hessite, 4) fine inclusions in tetradymite and 5) inclusions in limonite. Tellurides of noble metals include calaverite, petzite, hessite and an unidentified Ag and Pb sulfotelluride. Silver is also incorporated in acanthite and Hg-Ag-Sb-As, Pb-Bi-Ag and Cu-Ag-Pb-Bi sulfosalts. The Ag content of free native gold is 10–16 wt. % increasing to 20–24 wt. % in native gold in pyrite and in assemblage with hessite. Altaite, coloradoite and Ni and Pd tellurides are found in assemblages similar to noble metal mineralization. The formation temperature of chlorite from ore-bearing metasomatites is 339–392 °C. Fluid inclusions in quartz, calcite and albite are homogenized at a temperature range of 162–377 °C. The eutectic temperature (–23.5 °C) is typical of NaClKCl-H2O system. The ice melting temperature varies from –0.5 to –3.7 °C corresponding to salinity of 0.9– 6.0 wt. % NaCl-equiv.https://journal.mineralogy.ru/wp-content/uploads/2025/01/2024_10_4_7.pdfnaily depositmetasomatitesnative goldtellurides of noble metalssouth urals
spellingShingle A.D. Smirnitskaya
E.A. Rozhkova
E.V. Belogub
K.A. Novoselov
M.V. Zabotina
M.A. Rassomakhin
MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)
Минералогия
naily deposit
metasomatites
native gold
tellurides of noble metals
south urals
title MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)
title_full MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)
title_fullStr MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)
title_full_unstemmed MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)
title_short MINERALOGY AND ORE FORMATION CONDITIONS OF THE NAILY GOLD DEPOSIT (SOUTH URALS)
title_sort mineralogy and ore formation conditions of the naily gold deposit south urals
topic naily deposit
metasomatites
native gold
tellurides of noble metals
south urals
url https://journal.mineralogy.ru/wp-content/uploads/2025/01/2024_10_4_7.pdf
work_keys_str_mv AT adsmirnitskaya mineralogyandoreformationconditionsofthenailygolddepositsouthurals
AT earozhkova mineralogyandoreformationconditionsofthenailygolddepositsouthurals
AT evbelogub mineralogyandoreformationconditionsofthenailygolddepositsouthurals
AT kanovoselov mineralogyandoreformationconditionsofthenailygolddepositsouthurals
AT mvzabotina mineralogyandoreformationconditionsofthenailygolddepositsouthurals
AT marassomakhin mineralogyandoreformationconditionsofthenailygolddepositsouthurals