Formation Conditions of Host Rocks and Veins of Productive Deposits of the Astrakhan Gas–Condensate Field

Doklady Earth Sciences - One- (gas) and two-phase (aqueous solution plus gas) inclusions are studied in calcite taken from the Cheremshan horizon of the Bashkirian stage at a depth of...     

Selenium minerals in gold-bearing veins of the North Urals

The gold-bearing veins of the North Urals contain rare mineral selenium phases such as kawazulite, clausthalite, bohdanowiczite, volynskite, soucekite, naumannite, and eucairite, new for this region. They are largely observed as the finest inclusions in copper sulfides and closely associate with bismuth and tellurium minerals. Selenides were formed at the final oregenesis stages. Selenium was likely taken from the host rocks in the course of hydrothermal metasomatic processes initiated by granite intrusions.     

Conditions of the Formation of Unique Mineralization with Yushkinite V1 – xS · n[(Mg,Al)(OH)2] in Quartz–Calcite Veins,Pai-Khoi Ridge: Evidence from Study of Fluid Inclusions

Doklady Earth Sciences - The results of the study of fluid inclusions in quartz from quartz–calcite veins with unique yushkinite mineralization are reported. For the first time, it was proved...     

Growth condition of quartz crystals at the Zhelannoe deposit in the Nether-Polar Urals: Evidence from fluid and solid inclusions

The topography of various faces of quartz crystals indicates that the late growth of rock crystals occurred at a relatively slow rate, by the layer by layer mechanism activated by screw dislocations. The capture mechanism of gas-liquid inclusions by quartz at the deposit is identified, and gas-liquid and solid inclusions are examined in various quartz populations. The temperature of the mineral-forming processes is evaluated from the homogenization temperatures of the inclusions. Distinct quartz populations are determined to be formed under similar physicochemical conditions, at temperatures no higher than 260°C, which increased from earlier to later quartz populations. The quartz veins were produced by solutions of sodic-hydrocarbonate composition. The geochemical environment in which mineral-forming processes occurred at the Zhelannoe deposit was generally poor in fluid, and the inclusions are dominated by water and usually contain no more than 10 wt % carbon dioxide, strongly subordinated amounts of nitrogen and carbon monoxide, and no identifiable methane amounts.