Сибирский федеральный университет

Тип публикации: статья из журнала

Год издания: 2022

Идентификатор DOI: 10.17223/25421379/23/7

Ключевые слова: "invisible" gold, geochemistry, la-icp-ms, pyrite, sovetskoe gold deposit

Аннотация: The results of studying the distribution of trace elements (LA-ICP-MS) in the pyrite of the Sovetskoye gold ore deposit (Yenisei Ridge, Russia) are presented. The Sovetskoye deposit is located in the northern part of the Yenisei Ridge and is one of the largest and most developed for a long time within the Yenisei gold province. The deposit belongs to the gold-quartz type, and the main sulfide mineral is pyrite. Until now, no information has been provided on the distribution of trace elements in the pyrite of the deposit. We have studied pyrite from the host shales, quartz veins and their selvages, as well as coarse-crystalline pyrite. Electron microscopic studies have shown that the content of iron and sulfur in the studied samples varies within (wt.%): Fe 42.67–48.47; S 50.61–55.04. The deficiency in the anionic and cationic parts for some samples is compensated by the presence of impurities of arsenic (0.48-3.02 wt.%) and cobalt (1.71–3.38 wt.%). Taking into account the isomorphism (Fe↔Co; S↔As), the S/Fe ratio averages 1.98, which indicates a high chemical stoichiometry of the mineral. A total of 67 point determinations of trace elements were performed using the LA-ICP-MS method. The most typical (~ 90 % analyzes) impurities are, ppm: Co ~ 0.2–1700.0; Ni ~ 1.8–1300; Zn ~ 1.2–80.0; Ge ~ 3.0–5.7; As ~ 1.4–3700.0; Se ~ 4.6–50; Pb ~ 0.1–390.0. More than 50 % of analyzes also contain, ppm: Cu ~ 0.6–1000.0; Ag ~ 0.2–10.0; Sb ~ 0.04-13.00; Bi ~ 0.1–25.0. In about one third of analyzes, Te ~ 1.0–7.0 ppm and Au ~ 0.1–1.3 ppm were found. In single analyzes are present, ppm: V ~ 0.1–5.0; Cr 7.0; Mn ~ 39.0–110.0; Ga ~ 0.3–1.2; In ~ 0.2–0.9; Sn ~ 0.2–0.6; W ~ 0.5-2.1; Tl ~ 0.1–0.3. Mo and Cd contents are below the detection limit in all analyzes. The "invisible" gold is enriched in pyrite from quartz veins (~ 0.56 ppm) and coarse-crystalline pyrite (~ 0.83 ppm). Mineral from selvages of quartz veins and host shales contains less Au (~ 0.15 and ~ 0.16 ppm). The position of the points of composition on the Au-As diagram below the line of structurally bound gold indicates its isomorphic nature. However, the established concentrations of the metal are not of industrial significance, and the bulk of the gold at the deposit is present in native form. The studied pyrite varieties are enriched in silver relative to gold (Au/Ag from 0.09 to 3.75), the excess of silver can be associated in the form of ultrafine particles of Au-Ag sulfides, or in the form of compounds with Te, Se, Sb, Bi. The most contrastingly studied pyrite varieties differ in the content of Se and As. Pyrite from the host shales is characterized by the highest As and Se contents. Pyrite from quartz veins contains minimal As concentrations. Coarse-crystalline pyrite occupies a region of low Se and As contents. Pyrite from selvage quartz veins has a variable composition. Based on the Se content in ore pyrite, the temperatures of mineral formation were established: pyrite from the host shales ~ 343 °C; coarse-crystalline pyrite ~ 417 °С; pyrite from quartz veins ~ 456 °С; pyrite from selvages of quartz veins ~ 439 °С. These parameters of mineral formation show a significant heterogeneity of the temperature field in the area of ore formation. Keywords:. © 2022, Geosfernye Issledovaniya. All rights reserved.

Журнал: Geosfernye Issledovaniya

Выпуск журнала: Vol. 2022, Is. 2

Номера страниц: 112-126

ISSN журнала: 25421379

Издатель: Faculty of Geology and Geography, Tomsk State University

• Silyanov S.A. (Siberian Federal University, Krasnoyarsk, Russian Federation)
• Sazonov A.M. (Siberian Federal University, Krasnoyarsk, Russian Federation)
• Lobastov B.M. (Siberian Federal University, Krasnoyarsk, Russian Federation)
• Shadrina D.A. (Siberian Federal University, Krasnoyarsk, Russian Federation)
• Tikhonova K.A. (Siberian Federal University, Krasnoyarsk, Russian Federation)
• Medvedev N.S. (Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russian Federation)

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