Volume 27, 5, 2008 |
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N.A. Kurentsova, G.B. Udintsev, D.Ye.Teterin, I.A. Roshchina. The geology of Hubert Miller seamount, Marie Byrd seamounts Province, Amundsen Sea, West Antarctic 3 L.F. Mishin, V.V. Akinin, Ye.L. Mishin. New data on the age of magmatic rocks of the Okhotsk-Chukotka volcanogenic belt western sector 12 O.A. Melnikov, V.V. Yershov, Kim Choon Ung, Sen Rak Se. The dynamics of gryphon activity of gas-water lithoclastic (“mud”) volcanoes, and its relation to natural seismicity with reference to Yuzhno-Sakhalinsk Volcano (Sakhalin Island) 25 A.N. Filippov, I.V. Kemkin. The first finds of Late Tithonian and Middle-Late Albian radiolarian associations in volcanogenic-cherty formations on the right bank of the Amur River lower reaches, and their tectonic implication 42 V.M. Novikov, E.L. Shkolnik, Ye.A. Zhegallo, V.K. Orleanskiy. Features of formation of hypergene ferromanganese nodules (Russian Far East and Vietnam) 53 Yu.Ya. Vashchilov, N.K.Gaidai, O.V. Sakhno. The formation, tectonic evolution, and ore genesis of the Pautovskiy horst granitoids (northeast Russia) 65 E.G. Ivolga. Ore region locations in the lithospheric structures of the Russian Far East South and the adjacent China areas (from geophysical data) 75 V.M. Sharafutdinov, I.M. Khasanov, T.I. Mikhalitsina. Petrophysical zoning of the Natalka ore field 89 L.V. Eirish. Some geologic-geomorphological features of formation of gold-bearing placers in Priamurye 104 B.G. Saksin. Forecast ecological evaluation of the regional effect of rare and non-ferrous metal mining on the environment in eastern Russia 115 Anniversaries Yuri F. Malyshev (to the 75-th anniversary) 124 Vitaly G. Varnavsky (to the 80-th anniversary) 125 Obituries Lev I. Krasny (1911–2008) 126 In memory of Nikolai Alexeevich Shilo (7.04.1913–8.06.2008) 129 N.A. Kurentsova, G.B. Udintsev, D.Ye.Teterin, I.A. Roshchina The geology of Hubert Miller seamount, Marie Byrd seamounts Province, Amundsen Sea, West Antarctic The paper is devoted to the results of the joint Russian-German geodynamic investigations in the West Antarctic, carried out in the Amundsen Sea, South Ocean, on the Marie Byrd seamounts, near the foot of the continental slope of the Marie Byrd Land. The results were obtained during the expeditions of R/V «Polarstern» in 2001 (Cruise 18a) and 2006 (Cruise 23/4). The collected material on the Hubert Miller seamount (Marie Byrd seamounts Province) suggests a relict continental volcano-tectonic origin of the seamount, which makes it possible to infer heterogeneity of the Amundsen Sea floor, spatial-and-temporal combination of destruction processes of continental crust (against the spreading model), progressing thalassogenesis (oceanization-taphrogenesis) and rifting. The destruction stage is characterized by high postconsolidation mobility resulting in areal disintegration and high permeability of continental crust, and also tectono-magmatic activation. The main process during the reworking of continental crust is its magmatic substitution by basite-ultrabasite material of the mantle with subsequent formation of secondary oceanic crust and preservation of continental crust relics. The endogenic activity of the Earth is connected with transmagmatic fluids flowing from the melted core and causing transformations in the Earth’s crust and mantle. L.F. Mishin, V.V. Akinin, Ye.L. Mishin New data on the age of magmatic rocks of the Okhotsk-Chukotka volcanogenic belt western sector New data are offered on the age of magmatic rocks of the western sector of the Okhotsk-Chukotka volcanogenic belt, which includes the Ulya and Kuidusun volcanic zones. The zircon U-Pb SHRIMP method yielded four consecutive datings, 106 to 90 Ma for the upper part of the section of the Yemanrinskiy Suite and lower part of the section of the Ulya Group in the Ulya volcanic zone. In the Kuidusun volcanic zone, the Rb/Sr isotope system of voluminous volcanic intrusives was studied: Verkhne-Allakh – 115-107 Ma and Atarbai – 85 Ma. The U-Pb method based on the zircon weighted microportions yielded the granitoid age of the Sizindzhinskiy massif: adamellites – 91 Ma, and diorites – 90 Ma. New geochronological evidence suggests that the Selitkan-Sungari and the Okhotsk-Chukotka volcanogenic belt are coeval and form a single system of volcanic belts and zones – the Okhotsk-Sungari megabelt. O.A. Melnikov, V.V. Yershov, Kim Choon Ung, Sen Rak Se The dynamics of gryphon activity of gas-water lithoclastic (“mud”) volcanoes, and its relation to natural seismicity with reference to Yuzhno-Sakhalinsk Volcano (Sakhalin Island The paper deals with detailed information about the character and dynamics of gryphon activity of the Yuzhno-Sakhalinsk gas-water lithoclastic (“mud”) volcano obtained from visual observations during long periods between short-time volcano eruptions in 1959, 1979 and 2001, and especially during continuous long-time (from June 18 to September 3, 2005) monitoring in the summer of 2005. Apart from direct observation, the monitoring involved temperature and air pressure measurements three times a day (at 9 a.m., 12 a.m. and 18 p.m.), analogous temperature measurement of liquid lithoclastic mass infilling crater hollows of different-type gryphons three times a day, analogous measurement of gas quantity emitted by two largest and most active gryphons, and daily (at 12 a.m.) sampling of liquid lithoclastic mass for chemical analysis by the IÑP-AES method for five elements: Al, Fe, Ca, Mn, and Ba from the crater of the largest gryphon – Main or Central. The monitoring results were compared to the data on natural seismicity obtained by the “Dat” and “Datamark” system of digital seismic stations. As a result, the data obtained proved for the first time the earlier assumed direct cause-and-effect relation between the Yuzhno-Sakhalinsk gas-water-lithoclastic volcano activity – the dynamics of material composition of the liquid lithoclastic mass erupted by its Main gryphon, and regional-local natural seismicity. Incidentally, one of the measured elements (Al) plays a distinct prediction role. A.N. Filippov, I.V. Kemkin The first finds of Late Tithonian and Middle-Late Albian radiolarian associations in volcanogenic-cherty formations on the right bank of the Amur River lower reaches, and their tectonic implications The results of the lithologic-stratigraphic study of volcanogenic-cherty formations on the left bank of the Machtovaya River (right tributary of the Amur River) are given. Radiolarian associations of the end of the Late Tithonian, end of the Late Tithonian - Early Valanginian and Middle-Late Albian are found there for the first time. It is established that the stratigraphic succession of volcanogenic-cherty formations of this area consists of Latest Tithonian - Early Valanginian dark red and red-brown cherts associated with basalts in the lower part and Albian dark gray clayey cherts, greenish-gray siliceous tuff mudstone and tuff siltstone in the upper part. The replacement of the cherts by clayey cherts occurred, probably, in Aptian time. The composition, structure and age range of the examined assemblages of the Kiselevka-Manoma accretionary complex are different, which testifies to their dissimilar tectonic nature. V.M. Novikov, E.L. Shkolnik, Ye.A. Zhegallo, V.K. Orleanskiy Features of formation of hypergene ferromanganese nodules (Russian Far East and Vietnam) Ferromanganese nodules (pisolites), forming accumulations at the bottom of the Pliocene-Quaternary argillaceous deposits of the Russian Far East and Vietnam, are investigated. They are made up of both general minerals (authigenic vernadite, feroxigite, goethite, halloysite, and terrigenous quartz) and minerals intrinsic to northern (authigenic hollandite, lithioforite, and bernessite) or southern regions (authigenic alumoforite, lepidocrocite, ferrihydrite, gibbsite, and terrigenous ilmenite). The pisolites are considered as microbial colonies, in which manganese and iron oxides form biomorphoses.The dying and mineralization of microorganisms occurred in the course of the colony growth, sequentially from the center to the periphery of the nodules. The origin of iron-bearing pisolites was guaranteed by the oxidation geochemical barrier developed at the boundary of dense sedimentary clays and underlying highly porous, easily permeable products of basalt weathering. Yu.Ya. Vashchilov, N.K.Gaidai, O.V. Sakhno The formation, tectonic evolution, and ore genesis of the Pautovskiy horst granitoids (northeast Russia) The paper considers the problems of existence of the Priiskatelskiy and Pautovskiy Late Jurassic-Early Cretaceous granitoid massifs, erosionally unexposed, in the core of the Pautovskiy horst and the single (at a depth of 2 km) Orotukan-Sulukhtchan Late Cretaceous granite massif. The Orotukan-Sulukhtchan massif is fixed on the surface by outcrops of the Verkhneorotukan, Sulukhchan and Solnetchny granite massifs. The palingenic and anatectic formation of granitoid magma and its migration upward to the surface occurred in conditions of general Late Mesozoic crust basification and resulted in the origin of the Pautovskiy horst. The granitization of the near-surface parts of the Earth’s crust was accompanied with basification at depth levels of the granitoid magma origin (10–15 km). The contact metamorphosed sedimentary cover of the Pautovskiy horst granitoid core is promising for tin and rare-metal deposits and has no potential for gold deposits and ore occurrences. E.G. Ivolga Ore region locations in the lithospheric structures of the Russian Far East South and the adjacent China areas (from geophysical data Metallogenic interpretation of deep structure maps of the region (thickness maps for the lithosphere, the lithospheric mantle, and the crust, constructed from results of the quantitative geophysical data interpretation) and gravity maps (those for the observed and transformed gravity fields) has been made. Based on analysis of spatial locations of ore regions with respect to anomalies and morphological elements of the above maps, the following elements were distinguished as ore controlling indications: areas of reduced lithospheric mantle thickness interpreted as the asthenosphere top of different tectonic nature (mantle diapirs, rifts, local plumes, areas of delamination of subduction-collision zones, etc.); regional and local unconsolidation areas (areas of sialization of the lithosphere and source magmatism; crustal and mantle tectonic faults). The above indications allow us to do the following: a) to determine the type of ore-generating and ore-controlling structures of ore regions (crustal and mantle) and type of the ore substance transit (non-hampered, hampered and much hampered relationship to the mantle), b) to evaluate the potential of the known ore regions and to distinguish the perspective areas for revealing the new ore regions. V.M. Sharafutdinov, I.M. Khasanov, T.I. Mikhalitsina Petrophysical zoning of the Natalka ore field Petrophysical features of 1168 rock and ore samples taken in plan and in the section of the whole Natalka ore field were analyzed. 235 of them were studied by geologic and mineralogical methods with subsequent preparation of thin sections and polished sections. The general two-level petrophysical zoning of the ore field was recognized and proved. Its relations with ore sites, interzonal space, host altered rocks and mineral composition were established. Both levels of the established petrophysical zoning were traced within the bounds of the ore field along strike for 4 km and along dip for 800 m. The spatial-genetic relation of the subvertical zone of conductivity (confined to the Omchak ore cluster) with petrophysical changes, which reflect the established mineral composition and the structure of metasomatites and ores, was defined. L.V. Eirish Some geologic-geomorphological features of formation of gold-bearing placers in Priamurye The intensity of placer formation is governed by many factors, mainly, by the level of the erosional truncation of ore-bearing structures. Given their deep eroded nature and geologically lasting denudation, numerous, often large placers bearing fine gold, which lost ties with their parent sources and formed mainly at the expense of rewashing of unconsolidated deposits close to the ore-bearing orogenic belts of depressions, originate. Such placers are developed in many gold-bearing regions: Dambuki, Sutar, Yerik, and others. Rich placers with high-standard gold were formed at the expense of erosion of gold mineralization, which was metamorphosed by post-ore granitoids (Niman and Kerbi regions, Central Sikhote-Alin). B.G. Saksin Forecast ecological evaluation of the regional effect of rare and non-ferrous metal mining on the environment in eastern Russia The general forecast ecological map of the regions of rare and non-ferrous metal mining in eastern Russia has been generated. The necessity of making such documents is grounded, and possibilities of their use for solving ecological problems of raw material regions are defined. Patterns of distribution of the regional natural mining-and-technical systems that are conditioned by this kind of economical activity are described, and their comparative assessment in terms of ecological risk of development is offered, and also suggestions concerning monitoring are made. |