pdf № 267, March

DOI: 10.19110/2221-1381-2017-3-3-13

The paper deals with geological and structural features, hydrothermal alteration, ore types of the Petropavlovskoe gold deposit located in the North of the Smaller Urals volcano-plutonic belt being the part of the Middle Paleozoic island arc system of the Polar Urals. The ore-controlling role of porphyry diorite bodies of the latest phase of intrusion has been detected. There are two ore types: gold-sulphide (main for the deposit) and gold-enriched gold-low-sulphide-quartz. The morphology and parameters of the gold-bearing mineralized zones and ore bodies are characterized. The Petropavlovskoe deposit can referred to the gold-porphyry type on the base of its structural and morphological, mineralogical and geochemical features. Such specific features include: spatial association of gold mineralization with the bodies of porphyry intrusive phases; stockwork structure of gold-bearing zones; volumetric character of ore-alteration zoning and ore component distribution.

Keywords: the Polar Urals, Petropavlovskoe gold-porphyry deposit, lode gold-sulfide mineralisation, linear-stockwork structure.

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DOI: 10.19110/2221-1381-2017-3-14-19

The data on the composition of primary fluid inclusions in corundum of Sutara deposit were first obtained by Raman spectroscopy using a Horiba LABRAM HR 800 spectrometer. Their primary fluid inclusions contained daughter diaspore crystals, which had not been previously detected in the inclusions of Sutara corundums (Jewish Autonomous Region, Russian Far East). Using Selector software based on thermodynamic calculations reaction: 1/2·Al₂O₃ + 1/2·H₂O = AlOOH = AlOOH we found that the formation diaspore at CO₂ fluid occurred at a temperature 305 °С and did not depend on pressure. In the H₂O–CO₂ fluid, the balance of corundum — diaspore shifted in the high temperature section and detected dependence on pressure. Thus, for the known temperature and the composition of H₂O-CO₂ fluid the diaspore inclusion in corundum may serve as geothermometer.

Keywords: corundum; primary inclusions, diaspore, metamorphism, Selector software.

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DOI: 10.19110/2221-1381-2017-3-20-27

The morphology and composition of the chromium-ferrum metacolloidal nodules from the white carnallite rocks of the Verkhnekamskoe Deposit were investigated. The white carnallite rocks were formed during a tectogenesis by recrystallization of hematite- and goethite-rich carnallite rocks in the presence of acidic hydrogen-containing brines. The brines composition is determined by radiation oxidation of the isomorphic iron (II) and a radiolysis of the crystallization water. It is assumed that the chromium precipitated from sulfate-chloride colloids and later the iron precipitated from chloride brines. Aging of colloidal clots led to the formation of the akaganeite and Cr-akaganeite with a covellite and native phase inclusions.

Keywords: Verkhnekamskoe Deposit, multicomponent colloids, akaganeite, Cr-akaganeite, Fe₁₅Cr₄Si, Cr₂Fe.

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DOI: 10.19110/2221-1381-2017-3-28-34

The results of studying the composition of the Мiddle Riphean metaclastic rocks from the South Timan are summarized in the article. Lithological features and geochemical parameters of sandy shales allow us to conclude that sedimentation occurred on the continental shelf in a shallow marine basin with weak hydrodynamic regime and seasonal climate variations. Sandy interlayers are dominated by mineral and rock fragments redeposited from eroded older metasedimentary rocks. They also contain slightly altered volcanic and pyroclastic material.

Keywords: Riphean, metaclastic rock, composition, clastic material, sedimentation conditions.

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DOI: DOI:10.19110/2221-1381-2017-3-35-38

At present, works, devoted to modern volcanism, hardly affect such a property of volcanic lavas as bubbling. In this article the first results of the study of the bubbling properties of the products of the Tolbachik Fissure Eruption 2012–2013 are given. Planometric methods for analyzing rocks from their images were used and statistical calculations were made. As a result, five types of lavas were identified — from the least porous — dense to the most porous scoria. The type of lava is porous-vesicular with a cumulative volume of cavities of 30–55 %. With increasing porosity-vesicularity, the size of the voids and the degree of their elongation are directly correlated.

Keywords: Tolbachik, volcanic eruption, porosity-vesicular lava.

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DOI: 10.19110/2221-1381-2017-3-39-44

Copper-nickel sulphide mineralization is widespread in gabbro-dolerite bodies of Pay-Khoy (Ugra Peninsula) and characterized by a large presence of noble metals. The studies using X-ray microtomography and Raman spectroscopy obtained new data on noble metals tellurides from the Savabeysky mineralization. Microtomography is useful to determine palladium tellurides and further microprobe investigation. The Raman spectra of noble metals (palladium and silver tellurides) tellurides were obtained for the first time for the copper-nickel sulfide from Pay-Khoy ores.

Keywords: Pay-Khoy, Savabeysky mineralization, tellurides of noble metals, Raman spectroscopy, X-ray microtomography.

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