New data on mineralogy of the Sugur copper deposit, South Urals

Abstract

The previous and new data on minerals and mineral assemblages of the Sugur copper deposit in Sugur Mountains of South Urals are summarized. The ores of the deposit host abundant calcite, andradite, diopside, magnetite, chromite and serpentine together with pyrite, chalcopyrite, chalcocite, pyrrhotite, millerite, and rare baddeleyite. The genesis of the deposit was previously considered both contact-metasomatic and hydrothermal. The new data allow us to attribute copper mineralization to a skarn-carbonatite system, which is locally recognized in the Karabash ultramafc massif.

Nature of Perovskite Mineralization of Silicate-Carbonate Veins in the Margins of Kusinsko-Kopanskaya Layered Intrusion (South Urals, Russia)

“…All studied perovskite crystals exhibit twinning. The twin structure of natural perovskites is a result of a phase transition from the cubic to the orthorhombic system [14,19]. This structure is visible in cross-polarized transmitted light (Figure 6a-c).…”

“…Since its discovery, the perovskite mineralization in the Nazyam mountains has been attributed to skarns, which formed at the contact between the Kusinsko-Kopanskaya intrusion and the dolomites of the Satka formation [11]. However, emerging evidence that highlights a significant divergence between the perovskite mineralization and the rocks of the Kusinsko-Kopanskaya intrusion has led to the proposal of alternative origins, specifically metamorphic [12] and carbonatitic [13,14].…”

“…However, perovskites predominantly shaped as octahedrons {111}, rhombododecahedrons {110}, and tetracubes {320} are much less abundant; only in the Perovskite mine, a single crystal of such shape was found. The biggest diversity of crystal shapes is observed for perovskites from the Perovskite and Akhmatov mines [14]. A complicated combination of octahedrons {111}, rhombododecahedrons {110}, several tetracubes {210}, {320}, {730}, {520}, tetragonal trisoctahedrons {211}, trigon trisoctahedrons {221}, and rare hexoctahedrons {543} are typical for perovskites from the perovskite-magnetite-clinochlore-clinohumite-calcite and perovskitemagnetite-diopside-clinochlore-calcite parageneses of the Perovskite mine.…”

“…The LREE profile of the studied perovskites is compatible with that of ultramafic alkaline rocks, and the HREE profile aligns with that found in kimberlites (Figure 9). Additionally, small < 0.5 sm metasomatic perovskite grains from the garnet-vesuvianite skarn at the Akhmatovaskaya mine were analyzed for comparison [14]. These analyses of grains are characterized with significant REE depletion, with levels often near the mass spectrometer's detection limit, producing a sawtooth-shaped curve (Figure 9).…”

“…Currently, three models explain the formation of perovskite mineralization: the "skarn" model, which suggests that mineralization occurs through magnesian skarns at the contact between the Kusinsko-Kopanskaya intrusion and dolomites [11]; the "metamorphogenic" model, proposing that perovskite mineralization results from regional metamorphism [12]; and the "carbonatite" model, which associates it with endogenous activity on the Western slope of the Southern Urals [13,14,18]. Recent U-Pb dating of perovskites from mineral mines, showing ages between 486-535 Ma [18], along with earlier TIMS dating results, contrasts sharply with the age of the Kusinsko-Kopanskaya intrusion (1379 ± 8 Ma [15]).…”