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A comparative study of Au-Bi-siderite-sulfide Arkachan and Ag-Pb-Bi Mangaseyskoye deposits, Sakha(Yakutiya), Russiaтезисы доклада
- Авторы: Anikina E., Vikent’eva O., Bortnikov N.S., Gamyanin G.N., Prokof’ev V.Y.
- Сборник: Minerals, Rocks and fluids: alphabet and worlds of planet Earth. 2nd European Mineralogical conference
- Тезисы
- Год издания: 2016
- Место издания: Rimini, Italy
- Первая страница: 595
- Последняя страница: 595
- Аннотация: These deposits are hosted sedimentary rocks of Verkhoyansk fold and thrust belt. They are confined to an intersection of north-north-southern and north-eastern regional strike-slipe faults. A depositional sequence of ores, a composition of vein and ore minerals, fluid inclusions, REE distribution and stable isotopes (C, O, S) in minerals of Arkachan Au-Bi-siderite-sulfide and Mangazeyskoe Ag-Pb-Zn deposits have been studied. The Arkachan deposit was formed during 3 ore stages: main gold, silver–polymetallic, and silver–antimony stages. Three types of fluid inclusions (FI) in quartz and carbonates consisted of (I) liquid-rich H2O + CO2 ± CH4 + NaCl, (II) vapour-rich CO2 ± CH4, and (III) aqueous-saline solutions, are distinguished. The Thom and salinity of FI-I vary from 385 to 280°C and 18.8 to 26.2 wt.% NaCl equiv, respectively, those in FI-III range from 261 to 324°C and 3.7 to 9.5 wt.% NaCl equiv. The ����18O of quartz II changes from +13.6 to 16.3‰(SMOW); d18O and d13C of siderite vary from +13.6 to +17.7‰ (V-SMOW) and from –6.0 to –3.0 (VPDB), respectively. The range of ����34S from –5.7 to 16.0‰ (V-CDT) has been obtained for sulfides. Three types mineralizations are recognized at the Mangazeyskoe deposit: quartz-pyrite-arsenopyrite, quartz-carbonate-sulfide, silver-polymetallic. Fluid inclusions found in quartz and carbonates are subdivided in three types: (I) liquid-rich H2O + CO2, (II) vapour-rich CO2, and (III) aqueous liquid-vapour FI. Thom and salinity are in the range of 367-217°���� and 13.8-2.6 wt.% NaCl equiv in FI-I, 336-126°���� and 15.4-0.8 wt.% NaCl equiv in FI-III, respectively. The ����34S values of sulfide change from -7.4 to +7.1‰. The d18O and d13C values of carbonates vary from -9.1 to -2.9‰ (V-PDB) and from +13.5 to + 19.5‰ (V-SMOW), respectively. The deposits display common features: (1) three fluid types with a contrasting chemical composition, (2) there is evidence for fluid phase separation and fluid mixing, (3) isotope data suggest an involvement of magmatic fluid. The 40Ar/39Ar age of muscovite from Arkachan is 101.9±1.4 Ma. The U/Pb age of zircon from Mangazeyskoe deposit is 97.8±0.9 Ma. These events are presumably related to the formation of Okhotsk-Chukotka Andean-type active continental margins along the North Asia. An origin of hydrothermal systems is related to intrusions of granitoid stocks and dikes derived from mixed mantle–crustal magma. These processes are favorable for an association Sn, Ag-Pb-Zn and Au-Bi deposits related to granitoid magmatism within the West Verkhoyansk province.
- Добавил в систему: Прокофьев Всеволод Юрьевич