Том 9, № 3 (2023)
- Жылы: 2023
- Мақалалар: 5
- URL: https://journals.rcsi.science/2313-545X/issue/view/18832
Бүкіл шығарылым
Minerals and mineral assemblages
Glaukosphaerite from chromitites of the Voykar-Synya massif, Polar Urals – the first reliable find in Russia
Аннотация
Glaukosphaerite and mcguinnessite (carbonates of the rosasite-malachite group) are found in chromitites of the Burkhoyla area, which is located in the northern part of the Voykar-Synya ultramafic massif (Polar Urals). The minerals form green and bluish-green films, small crystals and spherulites (up to 0.3 mm) in cavities of weathered chromitites. This is the first reliable find of glaukosphaerite in Russia. The chemical composition of glaukosphaerite is as follows (wt %): 25.14 NiO, 0.44 CoO, 0.89 FeO, 34.45 CuO, 7.90 MgO, 21.65 CO2 (calc.), 8.86 H2O (calc.), total 99.33. The empirical formula calculated based on the cation sum is (Cu0.88Ni0.68Mg0.40Fe0.03Co0.01)2.00(CO3)(OH)2. The parameters of the monoclinic unit cell of glaukosphaerite calculated from the powder X-ray diffraction data are: a = 12.070(3), b = 9.363(2), c = 3.131(1) Å, β = 98.03(2)º, V = 350.3(3) Å3. The formation of these carbonates is related to supergene alteration of sulfides (pentlandite and bornite) in chromitites.
5-14
Сhemical features of dark miсas from calcite-nepheline-feldspar pegmatites of Ilmenogorsky alkaline block (South Urals)
Аннотация
The composition and structure of micas of the annite–phlogopite and siderophyllite–eastonite series in calcite-nepheline-feldspar pegmatites of the Ilmenogorsky miaskite block are studied. The composition of mica of the annite–phlogopite series depends on the formation conditions of pegmatites. The nepheline-feldspar pegmatite with a rock-forming calcite (mine no. 125) contains annite with higher Fe content (Ftot 0.67–0.73). A pegmatite with late calcite (mine no. 16) contains less ferruginous annite (Ftot 0.52–0.63) and phlogopite (Ftot 0.32–0.50). The mica of the annite-phlogopite series exhibits a direct correlation between the Fetotal and Al contents. The mica of the siderophyllite–eastonite series in calcite-nepheline-feldspar pegmatites formed later in assemblage with minerals of the pyrochlore group, baddeleyite, calcite, fluorite, magnetite and Nb-bearing rutile. The Fe content of micas affects the shift of the Raman bands in the studied Samples. Ferruginous siderophyllite, eastonite and their barium varieties are identified for the first time for the Ilmenogosrky-Vishnevogorsky complex.
15-25
Mineralogy of ore deposits
Bismuth minerals from Yugo-Konevo and Porokhovskoe tungsten deposits (South Urals)
Аннотация
A mineral assemblage including sulfosalts of the bismuthinite-aikinite (aikinite, bismuthinite, gladite, salzburgite, krupkaite, lindströmite, pekoite, friedrichite, hammarite), pavonite (makovickyite, cupromakovickyite, pavonite, dantopaite, mummeite), cupropavonite (cupromakopavonite, cupropavonite) and lillianite (lillianite s.s.) homologous series, as well as ángelaite, berryite, matildite, baksanite, ikunolite, tetradymite, hedleyite and native bismuth is identified in veinlet ores of the Yugo-Konevo and Porokhovskoe tungsten deposits (Chelyabinsk oblast, South Urals). The Bi minerals occur as individual grains or intergrowths in fluorite-muscovite-quartz veins with hübnerite and scheelite, inclusions in quartz and intersticial aggregates between pyrite, sphalerite and galena. Ángelaite, dantopaite, cupromakovickyite and cupromakopavonite are first found at the territory of Russian Federation and salzburgite, cupropavonite, makovickyite and mummeite are found for the first time in the South Urals.
26-49
Geochemical features of sulfides of the Aktash magnetite-polymetallic deposit, Western Karamazar, Tajikistan (LA-ICP-MS data)
Аннотация
The distribution of trace elements in sulfides from various ores of the Aktash magnetite-polymetallic deposit (Tajikistan) is studied using LA-ICP-MS method. Sulfides partly replace banded magnetite ores. Each sulfide type exhibits specific geochemical features. Galena from sulfide-magnetite ores contains the higher amount of elements of «high-temperature» association (Bi, Ag, Cu) than galena from pyroxene-sphalerite ores, which, in addition to Ag and Bi, also contains higher amount of elements of «medium-temperature» association (Se, Te, and Sb). Sphalerite from sulfide-magnetite and chlorite-pyrrhotite ores contains higher Fe, Cd and Mn amount than sphalerite from pyroxene-sphalerite ores, which is characterized by elevated Co and As contents. Pyrite is depleted in trace elements except for As, the content of which is maximum compared to other sulfides. The Ag, Se, Bi, Zn, Cd and Ni contents of chalcopyrite from chlorite-pyrrhotite ores are higher than in chalcopyrite from sulfide-magnetite and pyroxene-sphalerite ores. Chalcopyrite from pyroxene-sphalerite ores is characterized by elevated Pb, As, Ge, Te and Sb contents. Relatively high Co, Ni and Se contents are determined in pyrrhotite. In addition to Fe, Cu, Zn, Pb and Au, which form minerals in all types of ores, we suggest by-product extraction of following elements from complex sulfide-magnetite, chlorite-pyrrhotite and pyroxene-sphalerite ores (the Bi, Ag, Se and Te contents of galena and Cd content of sphalerite are shown in brackets): Bi (19520–24650 ppm), Ag (7907–9650 ppm), Se (397–606 ppm) and Te (276– 436 ppm) from galena concentrate and Cd (8525–27670 ppm) from sphalerite concentrate.
50-69
Discussions
Benard Cells – a possible mechanism of the formation of subaquatic and subfluidic stalactites
Аннотация
The mechanism of formation of stalactites in gravity field of the Earth during their formation in air and subaquatic and subfluidic (magmatic) systems is considered. If the systems represent the cavities in solid bodies with ambient capillary-porous space filled with liquids, then it locally yields the convective subsystems: the Benard cells fixed by the formation of stalactites. The phenomenon is illustrated on examples of malachite, goethite, chalcedony, quartz-feldspar and magnetite stalactites.
70-75