Se and In minerals in the submarine oxidation zone of a massive sulfide orebody of the molodezhnoe copper–zinc massive sulfide deposit,Southern Urals

For the first time, extremely high Se and In contents were determined for the pinches of massive sulfide orebodies that are composed of small-clastic layered sulfide sediments transformed during submarine supergenesis. Se (clausthalite and naumannite) and In (roquesite) minerals were found. Hydrothermal chalcopyrite, a significant amount of which is present in the clasts of paleohydrothermal black smoker chimneys, was the source of Se. Most of the amount of In was contributed during dissolution of clasts of hydrothermal sphalerite, which is unstable in the submarine oxidation zone in the presence of oxidized pyrite.     

Jusa and Barsuchi Log Volcanogenic Massive Sulfide Deposits from the Southern Urals of Russia: Tectonic Setting, Structure and Mode of Formation

The Jusa and Barsuchi Log volcanogenic massive sulfide (VMS) deposits formed along a paleo island arc in the east Magnitogrosk zone of the Southern Urals between ca 398 and 390 Ma. By analogy with the VMS deposits of the west Magnitogrosk zone, they are considered to be Baimak type deposits, which are Zn‐Cu‐Ba deposits containing Au, Ag and minor Pb. Detailed mapping and textural analysis of the two deposits shows that they formed as submarine hydrothermal mounds which were subsequently destroyed on the sea floor under the influence of ocean bottom currents and slumping. Both deposits display a ratio of the length to the maximum width of the deposit >15 and are characterized by ribbon‐like layers composed mainly of bedded ore and consisting principally of altered fine clastic ore facies. The Jusa deposit appears to have formed in two stages: deposition of colloform pyrite followed by deposition of copper–zinc–lead sulfides characterized by the close association of pyrite, chalcopyrite, sphalerite, galena, tennantite, arsenopyrite, marcasite, pyrrhotite, bornite, native gold and electrum and high concentrations of gold and silver. The low metamorphic grade of the east Magnitogorsk zone accounts for the exceptional degree of preservation of these deposits.     

Rapid Polarized Emission Variability of Blazar S5 0716+714 in Optical Range

Astronomy Reports - The results of polarimetric observations of blazar S5 0716+714, carried out with the 6-meter BTA telescope of the Special Astrophysical Observatory of the Russian Academy of...     

Behavior of Trace Elements during Oxidation of Sphalerite of the Irinovskoe Hydrothermal Sulfide Field (13°20′ N,Mid-Atlantic Ridge)

Geology of Ore Deposits - The formation of present-day seafloor sulfide deposits is accompanied by their continuous oxidation and crystallization of insoluble Fe oxyhydroxides, which absorb metals...     

Influence of the Technical Ecosystem of the Electric Power Plant (Vladivostok) on the Phytoplankton of the Japanese Sea

Water Resources - The structure of phytoplankton of the Sea of Japan (Peter the Great Bay), located in the zone influenced by the technical ecosystem of Vladivostok thermal electric power station...     

Biomorphic textures in the ferruginous-siliceous rocks of massive sulfide-bearing paleohydrothermal fields in the urals

The work is dedicated to first finds of bacteriomorphic and microfaunal textures in the ferruginous-siliceous rocks that are widespread among volcanosedimentary complexes of the massive sulfide-bearing paleohydrothermal fields in the Urals. The bacteriomorphs are represented by: (1) single filaments with a diameter of 8–10 μm across and 80–90 μm long; (2) fascicles of branched or twisted-fibrous hematitequartz filaments 1–4 μm in diameter and up to 100 μm long; (3) microtubular textures, 20–30 μm across and up to 500 μm long, closely interlaced with thin hematite-quartz filaments (3–5 μm in diameter); (4)and hematite-quartz filaments (with the axial channel 1 μm across) formed by chains of elongated-oval lumps. These textures closely associate in the ferruginous-siliceous rocks with the fossilized tubular organisms (60–120 μm in diameter), tentaculites, remains of radiolarian skeletons, foraminifers, and others. It has been established that accumulation of various elements, such as Fe, Si, Ca, P, Mn, Ba, Ti, and K that are associated with biomorphic structures, was accompanied by the formation of their own mineral forms. Biomorphic textures in the gossanites (ferruginous-siliceous rocks forming haloes around destroyed massive sulphide mounds) differ from jasperites (not associating with sulfide ores ferruginouse-siliceous rocks), in terms of abundance, diversity, and development of tubular organisms and tentaculites. Biomineralization of different degrees of preservation in the Paleozoic ferruginous-siliceous rocks can indicate the microbial influence on geochemical processes during the decomposition of initial hyaloclastic sediments, which contain an admixture of sulfides and carbonates, under low-temperature conditions accompanied by the formation of iron and silica.     

Associations of trace elements in the sulfides of black smokers from the Broken Spur,Menez Gwen,and Snake Pit hydrothermal fields

Thorough processing of a huge amount of analytical data from Electron-Probe Microanalyses (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) allowed us to define several trace-element associations in sulfides from three hydrothermal vent fields at the Mid-Atlantic Ridge (Broken Spur, Menez Gwen, and Snake Pit). The presence of such association may indicate the occurrence of certain mineral phases at the micro- and/or nano-scales.     

Astrometric CCD observations of visual double stars at the Pulkovo Observatory

We present the results of 3489 astrometric observations for 361 visual double stars performed in 2003–2007 with the 26-inch refractor of the Pulkovo Observatory. The angular separations between the components (ρ) and the position angles (θ) are given. The errors in these quantities are, on average, 0″.009 for ρ and 0°.40/ρ for θ, where ρ is the separation in arcseconds.