Volume 26, 5, 2007 |
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V.V. Zigulyov, V.E. Kononov, B.V. Levin. Geological structure of the sedimentary cover, and evaluation of oil-and-gas potential of the Deryugin basin (Sea of Okhotsk) 3 A.S. Astakhov, V.V. Sattarova, A.I. Svininnikov, N.V. Astakhova, Ì.Ì. Domanov, M.V. Ivanov. Manganese metalliferous sediments in the Deryugin Basin (Sea of Okhotsk): chemical composition and geological settling 13 N.A.Kurentsova, T.I. Frolova, G.B. Udintsev, I.A. Roshchina. Rock material from the bottom of the Weddell Sea, South Ocean 32 A.P. Sorokin, L.V. Eirish, V.M. Kuz’minykh. Precious metal mineralization in carbonaceous formations (based on the research data from the eastern regions of Russia) 43 A.A. Sorokin, N.M. Kudryashov, A.B. Kotov. The age and geochemical peculiarities of the Early Mesozoic granitoids of the southern part of the Bureya terrane (Far East) 55 L.P. Plyusnina, G.G. Likhoidov, V.P. Molchanov, Zh.A. Shcheka. Modeling of gold transfer during listwenite and rodingite formation as exemplified by the Ust’-Dep ophiolite complex (Upper Priamurye) 67 V.Yu. Zabrodin. Paleogeography of the Bureya foredeep in the Jurassic period (Far East) 77 Ye.B. Volynets, S.A Shorokhova. Late Triassic (Mongugayan) flora of Primorye, and its location within coeval floras of Eurasia 88 Discussions N.A. Shilo. The Witwatersrand, and the problem of ore formation 101 Reviews V.S. Pushkar. Marine Pleistocene of the Russian coasts 112 Jubilees The 75th birthday of Vladimir G. Sakhno 114 The 70th birthday of Levin Boris Vul'fovich 116 V.V. Zigulyov, V.E. Kononov, B.V. Levin Geological structure of the sedimentary cover, and evaluation of oil-and-gas potential of the Deryugin basin (Sea of Okhotsk) Results of interpretation of the refraction seismic survey materials obtained by the Institute of Marine Geology and Geophysics in the Deryugin basin southern part are cited. The geological-geophysical model is given, and a scheme of the sedimentary cover evolution of the study area (Late Cretaceous - Pleistocene) is offered. The data testify to a high hydrocarbon potential comparable to the adjacent oil- and gas-bearing shelf of northeastern Sakhalin. A.S. Astakhov, V.V. Sattarova, A.I. Svininnikov, N.V. Astakhova, Ì.Ì. Domanov, M.V. Ivanov Manganese metalliferous sediments in the Deryugin Basin (Sea of Okhotsk): chemical composition and geological settling The results of the study of the chemical composition and location of manganese metalliferous sediments are cited. They make up a surface sediment layer up to 30 cm thick, up to 40 km wide and 180 km in extent in the central part of the basin along the East Deryugin suture zone; the latter limits the Deryugin sedimentary basin on the east. The sediments are enriched with respect to background sediments in Mn by 35 times, Au, Ni, Zn, Co by 3-5 times, and locally, in Mo, V, Ba, Cu, Pb, and Hg. Their formation is presumed to be determined by several processes: precipitation of manganese and some trace elements from the sea water plumes occasionally formed above the hot vents in the northern part of the basin; sedimentation from anoxic bottom waters that are formed above the eastern boundary of the Deryugin sedimentary basin, and early diagenetic migration of manganese into surface sediments. N.A.Kurentsova, T.I. Frolova, G.B. Udintsev, I.A. Roshchina Rock material from the bottom of the Weddell Sea, South Ocean The paper is devoted to the results of the Russian-German geodynamic research in the West Antarctic (1994-2005). In 2005 joint research on the project of the 50th RAE (Russian Antarctic Expedition) “Bathymetry of the South Ocean” was carried out in the Weddell Sea during ANT XX11-3 cruise of the r/v “Polarshtern”. This research contributes to establishing heterogeneity of the Weddell Sea bottom, processes of destruction, taphrogeny (oceanization) and sea-floor spreading. The destruction of continental crust is accompanied by magmatic activation. The oldest passive depression of the Weddell Sea was formed at the taphrogenetic stage. Magmatic substitution of continental crust by basic and ultrabasic mantle material is the main process in the transformation of the former attended by the formation of secondary oceanic crust and preservation of relics of continental crust. The driving force of the endogenic activity of the Earth is transmagmatic fluid flows emerging from the melt core and causing material transformations of the Earth’s crust and mantle. A.P. Sorokin, L.V. Eirish, V.M. Kuz’minykh Precious metal mineralization in carbonaceous formations (based on the research data from the eastern regions of Russia The issue concerning the relation between precious metal mineralization and carbonaceous rocks such as black shales and brown coals was considered. The authors’ conclusions on the phase syngenetic, epigenetic and metamorphogenetic origin of gold-bearing deposits in the black shale formations and on the syngenetic and epigenetic precious metals accumulation in brown coals were confirmed. Data on the supply of gold and platinum metals to brown coals of the Upper Amur Region and Maritime Territory due to the destruction of the adjacent ore sources in the Cenozoic are given. The problem requires further investigation. The recommendations on the search for precious metals are also offered. A.A. Sorokin, N.M. Kudryashov, A.B. Kotov The age and geochemical peculiarities of the Early Mesozoic granitoids of the southern part of the Bureya terrane (Far East) An age of 185+1 Ma was established for one of the porphyry-like microcline biotitic granites of the southern part of the Bureya (Turan) terrane. These granites are characterized by a total value of K2O + Na2O > 8 %, the predominance of K2O over Na2O, and a moderate differential character of distribution of REE (La/Yb)n = 14.7–28.5). The geochronological data allow the conclusion that at least one of the Early Mesozoic episodes of granitoid magmatism in the Bureya terrane occurred in the Early Jurassic. It is suggested that one of the most probable geodynamic settings of the formation of Early Mesozoic granitoids is the collision between the North Asian, Sino-Korean cratons and the Amur superterrane which is located between the above cratons. However, one cannot rule out the subduction origin of the referred granitoids. L.P. Plyusnina, G.G. Likhoidov, V.P. Molchanov, Zh.A. Shcheka Modeling of gold transfer during listwenite and rodingite formation as exemplified by the Ust’-Dep ophiolite complex (Upper Priamurye By experimental and thermodynamic modeling gold transfer by chloride and carbonate-chloride hydrothermal solutions at 300 and 400oC isotherms and Ptot = 1 kbar was studied. The negative effect of CO2 on Au solubility in fluids was confirmed. The low values of gold solubility (mAu < 10-8) measured during the experiments explain its precipitation in the process of interaction of serpentinite and listwenite with acid ore-bearing solutions. Listwenite formation was initiated by orogenic granitoids superposed in the studied case on serpentinites and rodingites, and it affects decisively gold transfer in the unified ore-geochemical system. The described metasomatic processes in the Ust’-Dep ophiolites and gold content in its metasomatic rocks confirm the conclusion. V.Yu. Zabrodin Paleogeography of the Bureya foredeep in the Jurassic period (Far East) Based on standard methods of paleogeographic analysis, small-scale paleogeographic sketch maps of the Upper Bureya and Gudzhik depressions of the Bureya foredeep have been compiled for the Pliensbachian, Bajocian, Bathian, Callovian, and Tithonian. The features of settings and marine sedimentation in the Late Triassic and major part of the Jurassic period are described. Ye.B. Volynets, S.A Shorokhova Late Triassic (Mongugayan) flora of Primorye, and its location within coeval floras of Eurasia The taxonomical composition of Late Triassic floras of Primorye is specified. Four floral assemblages are established, and their brief characteristic is given. A comparison is made between the studied flora and coeval floras of Eurasia. It is shown that in the Carnian through the Early Norian flora formed in transitive (ecotone) conditions between the moderate and the subtropical paleoclimatic areas, while in the Middle Norian flora formation most likely occurred under a subtropical climate. |