First Data on Formation Conditions of the Zhilnoye Au–Ag Epithermal Gold Deposit (Eastern Chukotka,Russia)

The first data on study of individual fluid inclusions in the Zhilnoye deposit have been obtained. It has been found that the gold-bearing quartz veins of the deposit were formed by heterogeneous hydrothermal fluids with low salt concentrations (0.2–3.6 wt% equiv. NaCl under intermediate temperature conditions of 246–350°C). The fluid pressure was 80–160 bar corresponding to 0.3–0.6 km depths of formation under hydrostatic conditions. The parameters of the mineral-forming fluids of the Zhilnoye deposit correspond to typical parameters of the fluids of epithermal deposits.     

Volcano-plutonic centers: Typomorphic (source-related) mineralization-controlling structures in volcanogenic belts: Northeast Russia

The volcanic structures in the volcano-plutonic belts in East Russia and the Cenozoic volcanic belts in Kamchatka exhibit vastly different levels of erosion. The volcanic structures in the Sea-of-Okhotsk-Chukchi volcanogenic belt reflect the structure at different depths in the system-forming typomorphic ore-bearing features (volcano-plutonic centers or VPC). We consider an example, viz., the Kakhovka VPC, which is situated in the Balygychan-Sugoi depression of the Sea-of-Okhotsk-Chukchi volcanogenic belt and contains the Dukat world-class silver-gold deposit. We demonstrate the importance of volcano-plutonic centers for mineralization.     

3D Doppler Tomography of the X-Ray Binary System Cygnus X-1 from Spectral Observations in 2007 in the HeII λ 4686 Å Line

The results of a 3D Doppler tomography analysis for the X-ray binary system Cyg X-1 in the HeII λ 4686 Å line are presented. Information about the motions of gaseous flows outside the orbital plane has been obtained for the first time. Line profiles obtained in June 2007 on the 2-m telescope of the Terskol Branch of the Institute of Astronomy (Russia) and on the 2.1-m telescope of the National Astronomical Observatory of Mexico were used. A detailed analysis of these spectral data is presented: the distribution of the data in time, distribution of orbital phases for the projections, comparison of the line profile shapes for the data from two observatories. The geometry of the total transfer function obtained in the reconstruction is considered. The possibility of applying the profiles obtained to realize 3D tomography is justified. The resolution of the constructed 3D tomogram in velocity space is 60 × 60 × 40 km/s for V _x , V _y , V _z . Fifteen cross sections for 15 different V _z values perpendicular to the orbital plane are presented. The intensity distributions corresponding to the velocities of gaseous structures in the binary system are obtained. The reconstruction was realized using the radio-astronomical approach, developed for solving problems in tomography with a limited number of projections.     

Golʼtsovoe Ag–Pb–Zn Deposit (Northeastern Russia): Geological Setting,Mineralogy, Geochemistry,and Ore Formation Conditions

Geology of Ore Deposits - The Gol’tsovoe Ag–Pb–Zn-deposit (1600 t silver in ores with an average grade of 1025 g/t Ag) is located on the southeastern flank of the Dukat mining...     

Gold deposits in dikes of the Yana-Kolyma belt

The ore-bearing dikes widespread in the Yana-Kolyma metallogenic belt vary in composition from granite porphyry to lamprophyres, gabbromonzonite, and dolerite. The dikes make up suites tens of kilometers in extent and up to 8–10 km wide or fields a few thousand square kilometers in area. Previously, the ore mineralization was traditionally referred to the gold-quartz type superimposed on dikes. However, isotopic and thermobarogeochemical data indicate that the mineralization is close to an intrusion-related gold deposit. A deep magma chamber could have been a source of sulfur in sulfides from beresites and quartz veins hosted in the Kolyma dikes. The deposits considered in the paper are permissive for large economic reserves with low and medium Au grades.     

Geochemistry and U-Pb geochronology of zircon in garnet amphibolites from Kamchatkskii Cape Peninsula,eastern Kamchatka

The paper presents the first data on the geochemistry and U-Pb SHRIMP geochronology of zircon from garnet amphibolites whose fragments are hosted by the sole of the ophiolite complex of Kamchatskii Cape, eastern Kamchatka. The zircons compose a homogeneous sampling, have relatively small sizes, are unhedral, have no oscillatory zoning, and possess practically no inclusions. The chemistry and photoluminescent characteristics of the zircons testify to their metamorphic genesis. The U-Pb SHRIMP dates of the zircons (81.4±9.6 Ma) indicate that the metamorphism of the amphibolite complex took place in Campanian time in the Late Cretaceous. These dates seem to correspond to the peak of the high-pressure metamorphism, which is thought to be related to the origin of an ophiolite complex of the suprasubduction type and its uplift within the Kronotskii Island arc.