Gold–Telluride–Palladium Mineralization, a New Type of Mineralization in Gabbro-Dolerites of the Pai-Khoi Ridge (Yugor Peninsula, Russia)

Abstract

—Data on gabbro-dolerite pyrite–chalcopyrite–pyrrhotite, quartz vein sphalerite–chalcopyrite, and associated early and late gold–telluride–palladium mineralization of the Krutoi ore occurrence (Pai-Khoi Ridge, Yugor Peninsula) are presented. The early (magmatic) gold–telluride–palladium mineralization is represented by minerals of the ternary system Ag–Au–Cu, palladium antimonides and stibiotellurides, and platinum arsenides, and the late (hydrothermal) one, by minerals of the binary systems Au–Ag and Au–Pd as well as mercury, lead, and silver tellurides. Sudburyite and testibiopalladite have been first found in the Krutoi ore occurrence; moreover, testibiopalladite has been first discovered in the Pai-Khoi Ridge. Their chemical compositions and Raman spectra have been examined. The results of sulfide sulfur, oxygen, and carbon isotope studies of calcium-containing minerals of chalcopyrite–quartz veinlets suggest assimilation of the material of the host deposits by the ore-forming mantle fluids. The fluid inclusions in the veinlets are divided into nitrogen–methane and carbon dioxide–nitrogen according to the composition of the gas phase. It has been established that the mineral-forming fluids were poorly saturated with gas. Magnesium and calcium salts were predominant in them. The temperature of the formation of quartz in the chalcopyrite–quartz veinlets is close to 300–490 ºC, and sphalerite–chalcopyrite and associated late gold–telluride–palladium mineralization formed at temperatures not exceeding 260 ºC.

Cu and Au Mineralization of the Tolparovo Ore Occurrence: Evidence for the Formation of Redbed Copper Occurrences in Neoproterozoic Deposits of the Southern Urals

“…According to these studies, the temperature of the sphalerite-chalcopyrite paragenesis formation ranges between 230 and 350 °C, sometimes reaching up to 400 °C. [62,63]) and (b) compositions of Cu-containing native gold and silver (at %) from deposits/ore occurrences of various types (compiled according to [64][65][66][67][68][69][70]).…”

“…Together, these minerals are described, e.g., in the Sandaowanzi epithermal Au-Ag-Te deposit (Aihui District, Heihe, Heilongjiang, China), where they were deposited in the final stages of the hydrothermal process under oxidative conditions at a temperature of about 240 • C [81]. Hessite and empressite were also noted as part of the late gold-telluride-palladium mineralization in the gabbrodolerites of the Pay-Khoy Ridge (Yugorsky Peninsula, Nenets Autonomous Okrug, Russia) [67]. The formation temperature of silver tellurides in this ore occurrence does not exceed 260 • C.…”

“…It should be noted that native gold from the Tolparovo ore occurrence is chemically similar to that of rhodingites in mafite-ultramafite complexes and to gold, associated with gabbrodolerites (see Figure 8b). For example, similar gold compounds have recently been established as a part of a gold-telluride-palladium mineralization in gabbrodolerites of the Pai-Khoi ridge (Russia) [67].…”

“…In many cases, XRD studies show that Cu 3 Au 2 compounds are copperenriched cuproauride (cubic CuAu) or tetra-auricuprid (tetragonal CuAu) [64,95]. However, Cu-containing gold of such a chemical composition is often found in igneous deposits and the ore occurrences of gold [64,67,68,70]. It should be noted that native gold from the Tolparovo ore occurrence is chemically similar to that of rhodingites in mafite-ultramafite complexes and to gold, associated with gabbrodolerites (see Figure 8b).…”

“…Silver tellurides are characteristic of many epithermal gold-telluride deposits [81,[96][97][98] and are often found in deposits of other types (volcanic-hosted massive sulfide (VHMS), intrusion-related gold deposits (IRGD), etc.) e.g., [67,[82][83][84]99,100]. In metamorphogenic-hydrothermal and skarn deposits, gold and silver tellurides, in association with bismuth minerals (wittichenite and Bi-tellurides), are often noted as inclusions in hypogenic bornite [101].…”