Volume 30, 4, 2011 |
|
A.N. Didenko. 40 years of Yu.A. Kosygin Institute of Tectonics and Geophysics, Far East Branch, Russian Academy of Sciences 3 R.J.Gulenok, V.I.Isaev, V.J.Kosygin, G.A.Lobova, V.I.Starostenko. Estimation of oil-and-gas potential of se dimentary basins of the Far East and West Siberia from gravimetry and geothermy data 5 V.Yu.Timofeev, A.Yu.Kazansky, D.G.Ardyukov, D.V.Metelkin, P.Yu.Gornov, N.V.Shestakov, E.V.Boyko, A.V.Timofeev, G.Z. Gil’manova. Rotation parameters of the Siberian domain and its eastern framing in different geologic epochs 21 L.F. Mishin. Secondary quartzites and their relation to gold ore mineralization of the Svetloye deposit (Ulya trough, Okhotsk-Chukotka volcanogenic belt) 32 S.V. Zybrev. Stratigraphy structure and of the central part of the East Sakhalin accretionary wedge (Eastern Russia) 49 M. N. Luneva. Seismic anisotropy distribution beneath South Sakhalin 74 A.A. Chashchin, Yu.A. Martynov, A.B. Perepelov, N.I. Yekimova, T.P. Vladimirova. Physical-and-chemical conditions of formation and evolution of Late Pleistocene-Holocene magmas of the volcanoes Gorelyi and Mutnovskiy (South Kamchatka) 87 Obituary Stanislav G. Byalobzheskiy (18.11.1938-06.03.2011) 109 R.Yu. Gulenok, V.I. Isaev, V.Yu. Kosygin, G.A. Lobova, V.I. Starostenko Estimation of oil-and-gas potential of sedimentary basins of the Far East and West Siberia from gravimetry and geothermy data Oil geology interpretation of results of geodensity, geothermal and paleotectonic modeling of some sedimentary basins of the Far East region and the central part of West Siberia was made. Estimation was carried out of the prospects of Paleogene and Upper Cretaceous potentially oil-and-gas complexes of the Lunsk, Makarovsk, Aniva troughs, West Sakhalin rise, and the Middle Amur intermountain depression. A forecast was made of zones of petroleum accumulation in the preplate complex, and localization of the centers of Jurassic oil generation was defined at a new large oil field of the central part of the West Siberian plate - Yugorskiy arch. Experience in oil geology modeling within the structures of different tectonic plan, material composition and deposit age makes it possible to recommend the accepted methodical approach and technology of gravimetry and geothermy interpretation as universal and effective. Key words: gravimetry, geothermy, oil geology interpretation, Sakhalin, Priamurye, West Siberia. V.Yu. Timofeev, A.Yu. Kazansky, D.G. Ardyukov, D.V. Metelkin, P.Yu. Gornov, N.V. Shestakov, E.V. Boiko, A.V. Timofeev , G.Z. Gil’manova Rotation parameters of the Siberian domain and its eastern framing in different geologic epochs The analysis of the motion of tectonic blocks of the Earth in the junction area between the Eurasian plate and its surroundings has been made. The present-day stage is examined using space geodesy and seismology data. Different models of rigid plate movements for Eurasia are analyzed. The use of the model of Eurasia (northern part of Asia) is exemplified to determine rotation parameters of the Amur plate on the basis of GPS data for the Far East (Sikhote-Alin profile) and the Transbaikal region. The use of the model of the Amur plate is illustrated for the extension zone at its western boundary – the Baikal Lake depression in the epoch of the Kultuk earthquake (M = 6.3, 8/27/2008). Paleomagnetic data allowed us to determine the pole of rotation of the Siberian craton with respect to its fold framing during the Mesozoic from paleomagnetic evidence, and kinematic parameters were estimated. The constant position of the rotation pole in the relative coordinate system from the end of the Paleozoic to the Present testifies to the constancy of rotation of the Siberian domain in the structure of the Eurasian plate. Key words: rotation of tectonic plates, present-day stage, Mesozoic, GPS method, paleomagnetic method, Siberian domain, Eurasian plate. L.F. Mishin Secondary quartzites and their relation to gold ore mineralization of the Svetloye deposit (Ulya trough, Okhotsk-Chukotka volcanogenic belt) Hydrothermally altered rocks and their relation to gold ore mineralization of the Svetloye deposit in the Ulya trough (western sector of the Okhotsk-Chukotka volcanogenic belt) have been studied. The composition of the hydothermally altered rocks and ore mineralization are evidence that this area is a characteristic representative of the acid-sulfite type deposits. The hydrothermally altered rocks of the Svetloye deposit are represented by secondary quartzites of medium-temperature type with the developed alunite and dickite facies. The upper structural level in the massif of secondary quartzites is formed by a sheet-like deposit 30 km2 in areal extent, 300 m thick with a gentle (5-10°) periclinal occurrence with respect to the arcuate axis of the volcanic ridge. A number of local steep zones with a mainly keeled section, and also small in size (a few hundreds of m2) multilayered trough-shaped structures, whose bottom is 100-150 m lower than the level of the sheet-like part of the secondary quartzite deposit, have been recognized. All structures of the lower level are confined to the periclinal part of the volcanic ridge. They are marked by increased thicknesses of monoquartzites and display a smooth transition to the sheet-like part of the massif. Secondary quartzites show symmetrical zoning. The central zone in the sheet-like part is made up of alunite quartzites, which are framed by dickite quartzites. The latter are changed downsection by hydromicaceous and hydromicaceous-montmorillonite argillizites. Monoquartzites form axial zones in the lower-stage structures. In the cloak-shaped part of the deposit, monoquartzites occur as rare lenses and interlayers of low thickness, spatially related to the local lower-stage structures. Gold mineralization at the deposit is confined to the monoquartzites, to their porous varieties. Gold deposition occurred after quartz formation in the course of pore and cavity infilling with late colloform silica with barite, and with hypogenic jarosite. Key words: secondary quartzites, argillizites, Au deposits, acid-sulfate type, Ulya trough, Okhotsk-Chukotka volcanic belt, Russian Far East. S.V. Zybrev Stratigraphy structure and of the central part of the East Sakhalin accretionary wedge (Eastern Russia) The East Sakhalin accretionary wedge is a part of the Cretaceous-Paleogene accretionary system that evolved along the eastern margin of Asia in response to subduction of Pacific oceanic plates. It developed in association with the Early Cretaceous Kema-Samarga volcanic island arc and Late Cretaceous-Paleogene East Sikhote-Alin continental-margin volcanic belt. Structure litho- and biostratigraphy of the accretionary wedge was studied in the central part of the East Sakhalin Mountains along the two sections that traverse the Nabil and Rymnik litho-tectonic units (zones) crossing ~ 40 km of their width. An overall structure of the studied portion of the accretionary wedge is a pile of numerous east-verging tectonic slices. These slices (tens to hundreds of meters thick) consist of various siliciclastic deposits that formed along a convergent plate margin with lesser amount of oceanic pelagic chert and basalt and hemipelagic siliceous and tuffaceous mudstone. Siliciclastic deposits include trench-fill mudstone and turbidites and cover sequence deposits. The structure of the accretionary wedge was likely formed by off-scraping and underplating. Subsequent juxtaposition of the off-scraped and underplated portions of the wedge as well as cover sequence deposits likely occurred along out-of-sequence thrusts. Radiolarian biostratigraphy was used to constrain the ages of lithologies and timing of accretionary events for different parts of the accretionary wedge. Radiolarian assemblages were correlated to the radiolarian range chart for the Tethyan regions by means of the unitary associations method. In the Nabil zone, ages of pelagic chert range from Late Jurassic, Tithonian to Early Cretaceous, Barremian. Ages of hemipelagic deposits are early Aptian to mid Albian, and ages of trench-fill and cover sequence deposits are mid-late Albian. In the Rymnik zone, ages of chert range from Late Jurassic to Early Cretaceous, mid Aptian. Ages of hemipelagic deposits are mid Aptian to mid Cenomanian, and ages of trench-fill and cover sequence deposits are mid-late Cenomanian. Younging of stratigraphic boundaries between different lithologies occurred in the easterly trenchward direction. The timing of accretion was constrained by the ages of trench-fill and cover sequence deposits. Accretion occurred from the end of the Aptian to mid Albian in the western part of the Nabil zone, and in the mid Cenomanian in the eastern part of the Rymnik zone. The western part of the Nabil zone was accreted synchronously with the Kiselevka-Manoma accretionary wedge located to the east, on the continent. Both accretionary wedges are thought to have formed along a single convergent plate margin, with Sakhalin accretionary system located to the south of the Kiselevka-Manoma accretionary wedge in the Albian. Key words: structure, stratigraphy, Radiolaria, Mesozoic, accretionary tectonics, Sakhalin, Eastern Russia. M. N. Luneva Seismic anisotropy distribution beneath South Sakhalin Shear wave splitting parameters from local deep focus and crustal earthquakes beneath South Sakhalin and Northern Hokkaido have been measured. The study of the split shear wave amplitude, polarization and splitting parameter distribution reveals their interrelationship with the subducted Pacific Plate geometry and horizontal heterogeneity of the rheological properties/viscosity of the medium. Comparison of observed data with those modeled in anisotropic media allows a mantle flow to be NNW-oriented beneath South Sakhalin and Northern Hokkaido. Based on the split shear wave time delays mantle anisotropy degree is estimated to be around 1-2% beneath South Sakhalin and 1.5-2.5% beneath Northern Hokkaido. A relatively high anisotropy (2-15%) from local crustal earthquakes is found beneath the Central Sakhalin Fault. Key words: seismic anisotropy, shear wave splitting, crust and deep-focus earthquakes, South Sakhalin A.A. Chashchin, Yu.A. Martynov, A.B. Perepelov, N.I. Yekimova, T.P. Vladimirova Physical-and-chemical conditions of formation and evolution of Late Pleistocene-Holocene magmas of the volcanoes Gorelyi and Mutnovskiy (South Kamchatka) The detailed study of mineralogical and geochemical compositions of major effusives of the modern structures of Gorelyi (Q3 4–Q4 4) and Mutnovskiy (Q32–Q4) volcanoes, and also the results of numerical modeling (“Comagmat” program) made it possible to estimate the role of fractional crystallization, fluid regime and geodynamic conditions in petrogenesis of the investigated basaltoids. The specific features of evolution of magmas of the two volcanoes give grounds to conjecture that beginning from the Late Pleistocene (Q34) the whole study territory experienced a change in geodynamic regime attended by the strengthening of the role of tension stresses in its development. Key words: basalts, mineralogy, geochemistry, Mutnovskiy Volcano, Gorelyi Volcano, Kamchatka. |