The Gold Mineralization of the Baranyevskoe Au-Ag Epithermal Deposit in Central Kamchatka

Abstract

The Baranyevskoe Au-Ag epithermal deposit of low-sulfidation (LS) type is located on the Kamchatka Peninsula in the Neogene-Quaternary Central Kamchatka Volcanic Belt, where Au-bearing quartz veins are usually accompanied by veinlet stockworks. Two economic associations are typical of the Baranyevskoe deposit. The first corresponds to gold-pyrite-quartz association with low-grade native gold (521–738‱) intergrown with pyrite. Some accessory Au-Ag minerals within the early association were also identified: acanthite AgS2, hessite AgTe2, lenaite Ag(Fe,Cu)S2, petzite Ag3AuTe2, utenbogardite Ag3AuS2 and unnamed Ag-Sb-As sulfosalts. The former Au-Ag minerals were most likely formed in the temperature range of 320–330 °C based on the study of arsenopyrite thermometers and fluid inclusions. The second, a gold-sulfosalt-quartz association, includes high-grade native gold (883-941‱) in intergrowth with chalcopyrite. Cuprous phases (bornite, chalcocite, heerite, native copper, Cu-Zn solid solutions), Bi-rich sulfosalts (aikinite PbCuBiS3, emplectite CuBiS2, witticenite Cu3BiS3), stannoidite Cu8Fe3Sn2S12, mawsonite Cu6Fe2SnS8), Au-bearing galena, Te-free and Bi-rich tetrahedrite-tennantite represent this association. Fluid inclusions in gold-sulfosalt-quartz association are characterized by homogenization temperature ranging from 226 to 298 °C, and salinity from 0.4 to 1.2 wt. % NaCl eq.

Au-Ag-Se-Te-S Mineralization in the Maletoyvayam High-Sulfidation Epithermal Deposit, Kamchatka Peninsula

“…Selenium atoms in the structure of sulfides substitute sulfur in sulfides and sulfosalts, even at low H 2 Se/H 2 S values, as observed in many low sulfidation epithermal deposits. In particular, it is typical for the Rodnikovskoye and, to some extent, the Baranievskoye deposits in Kamchatka [21,22].…”

Tolstykhite, Au3S4Te6, a new mineral from Maletoyvayam deposit, Kamchatka peninsula, Russia

“…Unlike other epithermal deposits of the Central Kamchatka volcanic belt, which belong to the low-sulfidation type, the Maletoyvayam deposit is assigned to the high-sulfide one (Sidorov et al , 2020; Tolstykh et al , 2018, 2020, 2022). The Maletoyvayam deposit is composed of andesites, tuffs and tuffaceous sandstones.…”

“…The main ore minerals include pyrite and gold. A detailed description of the Maletoyvayam deposit, its geology, geochemical features and mineralisation can be found elsewhere (Kalinin et al , 2012; Shapovalova et al , 2019; Sidorov et al , 2020; Tolstykh et al , 2018, 2020, 2022).…”

“…Herein, we provide the description of the third mineral of the above system coming from the same occurrence that we named tolstykhite (pronouncing: tol sty khait; cyrilic -толстыхит) in honour of Russian mineralogist Dr. Nadezhda Dmitrievna Tolstykh (Надежда Дмитриевна Толстых), born October 7 th , 1954, for her contributions to the mineralogy of gold and platinumgroup elements (PGE) and study of ore deposits. Dr. Sobolev Institute of Geology and Mineralogy, Novosibirsk, Russia and the author of numerous publications focused on the mineralogy, geology and geochemistry of noble minerals (see, e.g., Tolstykh et al, 2008Tolstykh et al, , 2009Tolstykh et al, , 2018Tolstykh et al, , 2019Tolstykh et al, , 2021. In addition, she is the discoverer and author of several noble minerals, including maletoyvayamite and gachingite mentioned above.…”

“…Dr. Tolstykh is the leading researcher at the Sobolev Institute of Geology and Mineralogy, Novosibirsk, Russia and the author of numerous publications focused on the mineralogy, geology and geochemistry of noble minerals (see, e.g. Tolstykh et al, 2008Tolstykh et al, , 2009Tolstykh et al, , 2018Tolstykh et al, , 2019Tolstykh et al, , 2020Tolstykh et al, , 2021. In addition, she is the discoverer and author of several noble minerals, including maletoyvayamite and gachingite mentioned above.…”