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Copper mineralization in the Magadan oblast (Northeast of Russia) has been established in Middle–Upper Riphean quartz–chloritoid and chlorite shales of the of the Prikolymsky terrane. Compared to the upper crust, copper shales of the Oroek ore occurrence are noticeably enriched in a narrow range of trace elements: Cu, Ag, Au, Rh, and Se, with enrichment factors ranging from 10-fold (Se, Rh) to 100-fold (Ag, Au) and even 1000-fold (Cu) suggesting, apparently, their synchronous involvement in ore formation. In addition, the studied samples are slightly enriched in Cd, Li, Co, Zn, V, U, Sc, Y, and REE. Copper shales show relatively flat rare earth element (REE) patterns similar to the chondrite-normalized pattern and have no distinct positive or negative Eu anomalies and are dominated by light lanthanides. The Ce/Ce* and Eu/Eu* ratios indicate that ore formation proceeded under oxidizing conditions. The geochemical data we obtained show that the Riphean host rocks could serve as a source of trace elements and REE ore-forming fluids. In the ores, covelline and chalcocite are the main copper minerals; less common are roxbyite, idaite, nukundamite, spioncopite, chalcopyrite, silver-bearing (Ag about 1 wt %) bornite, and yarrovite, as well as native gold. Fluid inclusions in quartz suggest that copper mineralization was formed at temperatures of 212–190°C and a pressure of 1 kbar from hydrothermal solutions of medium salinity (from 13.8 to 12.4 wt % eq NaCl) and high density (0.95–0.98 g/cm3) saturated with chlorides of Ca, Mg, and K. The copper shales of the Prikolymsky terrane differ from sedimentary copper and copper shales of the African Copper Belt in low Co and Ni contents and from the Kupfershifer in low Pb and Zn contents. The results we obtained can be used for predicting new deposits. [ABSTRACT FROM AUTHOR]

Trachyrhyolite and comendite of the Pechalninskii ore field contain high potentially commercial concentrations of a number of rare metals and REEs. The enrichment coefficients vary from several (Zn, Ga, and LREEs) to tens (Be, Y, Zr, Nb, Rb, and HREEs) of times. The REE distribution is indicative of uniform enrichment in HREEs relative to LREEs at (La/Yb)N in the range of 0.16–1.01. All samples are distinguished by highly negative Eu anomalies with Eu/Eu* = 0.13. Based on a comparative analysis with similar world-known fields in alkali volcanic rocks, the Pechalninskii ore field could become an unconventional large-volume HREE source. [ABSTRACT FROM AUTHOR]

The paper presents data on quartz-hosted fluid inclusions in commercial ores of various type (veinlet−disseminated and vein) of the Verninskoe gold deposit. The ores of various types were found out to significantly vary in the values of some of their physicochemical parameters of the fluids and in the composition of these fluids. The fluids that formed the gold veins have a somewhat higher initial temperature (356–246°C), a higher density of carbon dioxide in gas inclusions (1.00–0.84 g/cm3), and a higher fluid pressure (3170–1390 bar) than those of the fluids that formed the veinlet–disseminated ores (330–252°C, 0.87–0.54 g/cm3, and 1960–570 bar, respectively). The fluids that formed the gold veins were enriched in CО2, Sr, Ag, Ga, Ge, Mn, Fe, Ni, Sn, Ba, and REE, whereas the fluids that formed veinlet–disseminated mineralization were richer in , Br, Sb, V, and Au. This situations may be explained by the interaction of the deep fluid with the terrigenous host rocks in the course of ore deposition. When vein quartz crystallized in relatively wide fractures, the fluid interacted with host rocks and changed not as much as when the veinlet−disseminated ores were formed in narrow fractures. The initial parameters of the fluid that formed the vein quartz were thus the closest to the characteristics of the fluid that transported the ore components, and the comparison of these data with the parameters of the fluids that formed the veinlet–disseminated mineralization demonstrates that they changed in the course of ore deposition. The mineral-forming fluids likely came from a deep-sitting source, and the mineral-forming processes may have involve granitoid-derived fluids. [ABSTRACT FROM AUTHOR]

The Kuroko-Type ores of Hotaidokh deposit are enriched in a wide range of elements, compared to the average contents of elements in the upper crust. The REE spectrum of ores is dominated by light 'hydrophilic' lanthanides of the 'yttrium' group. The ores are characterized by low REE total contents, sharp positive Eu anomalies, as well as δEu ≫ 1, δCe < 1, and the average ratio Y/Ho ~ 48.13. Such index values indicate the deposition of ore minerals from high-temperature hydrothermal fluids becoming cold in an oxygen-bearing depth of a seawater body when the redox conditions change. Consequently, the pyritepolymetallic ores of the Hotaidokh deposit were formed from ore-forming fluids of an exhalation-hydrothermal origin. It should be noted that the data presented in this work on the composition and distribution of a number of trace elements and REEs in Kuroko-type ores of this deposit were obtained for the first time. [ABSTRACT FROM AUTHOR]

Ores of epithermal Au-Ag deposits of the Okhotsk-Chukotka volcanoplutonic belt are characterized by enrichment in a wide spectrum of elements in relation to the average upper crustal values. The data obtained show that the host volcanic rocks are the most likely sources of minor elements and REEs for the fluids that formed epithermal Au-Ag deposits of the Okhotsk-Chukotka volcanoplutonic belt. [ABSTRACT FROM AUTHOR]

This paper is concerned with the geochemical features and conditions of generation for Paleozoic Au-Ag mineralization in the pre-accretionary Kedon (D) volcano-plutonic belt (KVB), which is situated within the Omolon cratonic terrane (Northeast Russia). We present new data on the compositions and concentrations of trace elements and rare-earth elements (REEs) in the host rocks and volcanogenic ores of epithermal Au-Ag fields. The ores are found to be enriched in a wide range of trace elements. The general features of the ores under study include a low level of REE concentrations, an obvious enrichment in light REEs, and considerable variations in europium anomalies, ranging from low negative to low- and strongly positive. Fluid inclusions were studied to show that the ore-forming solutions were hydrocarbonate potassium in composition. The mineral content of the fluid increases toward later, low-temperature phases of the mineralization. We found a tendency of potassium increasing from the earlier oreless quartz to productive quartz going to great depth, as well as a slow decrease in the concentrations of Na, Ca, and Cl. The productive quartz shows direct correlation in Ag-K and a reverse correlation in Ag-Na. The results indicate andesite magmas and meteoric water as the most likely sources of the fluids that have formed epithermal Au-Ag ores in the KVB deposits. [ABSTRACT FROM AUTHOR]

The satellite MITA, carrying on board the scientific payload NINA-2, was launched on July the 15th, 2000 from the cosmodrome of Plesetsk (Russia) with a Cosmos-3M rocket. The satellite and the payload are currently operating within nominal parameters. NINA-2 is the first scientific payload for the technological flight of the Italian small satellite MITA. The detector used in this mission is identical to the one already flying on the Russian satellite Resurs-O1 n.4 in a 840-km sun-synchronous orbit, but makes use of the extensive computer and telemetry capabilities of MITA bus to improve the active data acquisition time. NINA physics objectives are to study cosmic nuclei from hydrogen to iron in the energy range between 10 MeV/n and 1 GeV/n during the years 2000–2003, that is the solar maximum period. The device is capable of charge identification up to iron with isotope sensitivity up to oxigen. The 87.3 degrees, 460 km altitude polar orbit allows investigations of cosmic rays of solar and galactic origin, so to study long and short term solar transient phenomena, and the study of the trapped radiation at higher geomagnetic cutoff. [Copyright &y& Elsevier]