Том 31, 4, 2012 |
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Yu.F. Malyshev, M.V. Goroshko, V.B. Kaplun, N.P. Romanovsky, V.G. Gurovich. Geophysical characteristics and metallogeny of eastern Aldan-Stanovoy Shield (Far East) 3 P.L. Nevolin, V.P. Utkin, A.N. Mitrokhin, T.K. Kutub-Zade. Geologic structure of Western Primorye: structurization dynamics 17 G.L. Kirillova, V.V. Krapiventseva. Mesocyclicity of Upper Triassic-Jurassic deposits of the Bureya Basin: tectonics, eustasy, and sequence stratigraphy (Far East) 38 B.I. Pavlyutkin, I.Yu. Chekryzhov, T.I. Petrenko. Stratigraphy of Oligocene-Miocene boundary deposits of the Nezhinsky brown coal field (Primorye) and the problem of Paleogene-Neogene boundary in the region 55 N.G. Razzhigaeva, L.A. Ganzey, T.A. Grebennikova, L.M. Mokhova, H.A. Arslanov, T.A. Kopoteva, A.V. Rybin. Evolution of lacustrine-swamp sedimentary environments of an ancient caldera of Rasshua Island, Central Kuril Islands, in Holocene 74 A.I. Obzhirov, I.K. Pushchin, E.V. Korovitskaya. Distribution of hydrogen and hydrocarbon gases in the Tonga island arc system 87 L.F Simanenko, O.I. Sharova, S.A. Shcheka. New data on titanomagnetite exsolution textures from pyroxenites of the Koksharovsky massif (Primorye) 93 Yu.A. Mamaev, V.S. Litvintsev, V.S. Alexeev. Processes of a productive layer formation of the noble metals technogene 106 S.I. Levshina. Manganese distribution in the surface waters of Middle and Lower Priamurye 113 Anniversaries Avchenko O.V. (to the 70-th anjniversary) 120 Memorial dates Marina Alexeevna Favorskaya (100th birth anniversary) 121 Yu.F. Malyshev, M.V. Goroshko, V.B. Kaplun, N.P. Romanovsky, V.G. Gurovich Geophysical characteristics and metallogeny of eastern Aldan-Stanovoy Shield (Far East) Data on geophysical surveys have been generalized, and magnetotelluric sounding along the Zeya water storage basin-Algama River profile has been conducted. The Bomnaksky mantle plume structure has been distinguished for the first time. Areas prospective for ores have been defined and substantiated. Key words: geoelectric modeling, aerogamma-ray spectrometric anomalies, areas prospective for ores, Aldan-Stanovoy Shield, Far East. P.L. Nevolin, V.P. Utkin, A.N. Mitrokhin, T.K. Kutub-Zade Geologic structure of Western Primorye: its structurization dynamics The results of investigation on structurization dynamics for Western Primorye are discussed for the first time. The least studied macro- and meso-levels of geologic space were examined by the analysis of structural parageneses. These fundamentals allowed us to establish 3 geostructural sequentially-superposed planes (parageneses), each of which was under its stress field. The formation time for each of the geostructural parageneses corresponds to a separate geodynamic period, as following: Late Proterozoic/Early Paleozoic, Middle/Late-Paleozoic, and Mesozoic/Cenozoic. During the first two episodes of geodynamic activization (Late Proterozoic/Early Paleozoic) period the main compression axis was oriented longitudinally. The first episode was characterized by formation of thrust-folded geostructural pattern. The second episode resulted in superposition of the meridional riftogenic structures and caused a normal fault-extension segmentation of the crystalline basement into meridional blocks which partially correspond to the earlier recognized terranes. Owing to the latitudinal compression and oblate deformation predominant in the Middle/Late Paleozoic geodynamic period, downdip and upstanding blocks were transformed into depressions and arches, respectively. The depressions were filled with Paleozoic sediments, whereas initial rocks of the arches experienced granitization accompanied by formation of two granitic assemblages which joined the terranes. The granites are characterized by shadow and shear-type fold and pseudofold forms. The Mesozoic-Cenozoic period (being under the NNW compression) is subdivided sequentially into Triassic-Jurassic, Early Cretaceous, and Tertiary tectonic episodes. During the Triassic-Jurassic episode, narrow ENE-trending arches and depressions were formed as a result of warping. The arches accumulated granitizied rocks, and the depressions were filled with Early/ Late Triassic volcanogenic-sedimentary sediments. In such a way, structural complexes overlapping to the strike more ancient formations of the meridional blocks (terranes) developed. The following two Mesozoic-Cenozoic episodes manifested themselves as a discrete formation of coal depressions being under the NNW compression (in combination with the ENE extension) by superposition on the warping products. Key words: structurization dynamics, structural parageneses, stress fields, geodynamic periods, Western Primorye, Far East. G.L. Kirillova, V.V. Krapiventseva Mesocyclicity of Upper Triassic-Jurassic deposits of the Bureya Basin: tectonics, eustasy, and sequence stratigraphy (Far East) Mesocyclicity of Upper Triassic-Jurassic deposits of the Bureya Basin located at that time at the paleocontinent margin, was examined. The sections of this basin distinctly reflect the chronology of eustatic fluctuations of sea-level enabling for the first time construction of a sequence stratigraphic model for this basin. Six-order cycles were recognized in the Bureya Basin for the Jurassic stage of its evolution from the factors affecting the cyclicity. The tectonic factor is predominant while distinguishing the first three ranks (orders): the Alpian first-order cycle, Indosinian and Yanshanian second-order cycles, Late Indosinian, Early Yanshanian and Middle Yanshanian subcycles of the third-order cycle. The formation of the fourth- to sixth-order cycles was effected alongside the tectonic processes by eustatic fluctuations of the sea-level, sediment supply, sedimentary environments, and climatic changes. As the source rocks generate during maximal transgressions, aleuropelitic strata of the Chagany, Elgi, Epikan, and Sinkalnin suites and Khavagdin series accumulated in the deepest parts of the basin and those constituting the fifth-order cycles are believed to be the most prospective objects. Key words: mesocyclicity, tectonics, eustasy, lithology, sequence stratigraphy, Jurassic, Bureya Basin, Far East. B.I. Pavlyutkin, I.Yu. Chekryzhov, T.I. Petrenko Stratigraphy of Oligocene-Miocene boundary deposits of Nezhinsky brown coal field (Primorye) and the problem of Paleogene-Neogene boundary in the region The paper gives the geological characteristics of the productive coal-bearing strata and overlying deposits (Nezhinsky bed) of the Nezhinsky brown coal deposit. Detailed geological and paleobotanical evidence are presented on the Nezhinsky bed section (a quarry being in operation), which is suggested to be typical for it. Based on the analysis of macro- and microfloral assemblages, it was concluded that the studied deposits are of the Late Oligocene-Early Miocene transitional age. The floras from both the beds don’t exhibit any principal differences, and belong to the heat moderate type, but the Nezhinsky flora is more thermophyllic. It is pointed to the probability of a stratigraphic break between the coal-bearing and Nezhinsky beds. The similarity to the sections of the boundary Oligocene-Miocene deposits of the adjacent regions is noted. The age of the Nezhinsky bed is Early Miocene. It is likely that this age corresponds to the Late Aquitanian-Burdigalian interval of the International stratigraphic scale. In Primorye, the boundary between Paleogene and Neogene is proposed to be drawn along the roof of the Pavlovsky horizon, and at the Nezhinsky brown coal deposit – along the roof of the coal-bearing bed. Key words: stratigraphy, Upper Oligocene, Lower Miocene, coal-bearing strata, Nezhinsky deposit, fossil flora, Paleogene-Neogene boundary, Primorye. N.G. Razzhigaeva, L.A. Ganzey, T.A. Grebennikova, L.M. Mokhova, H.A. Arslanov, T.A. Kopoteva, A.V. Rybin Evolution of lacustrine-swamp sedimentary environments of an ancient caldera of Rasshua Island, Central Kuril Islands, in Holocene Evolution stages of lacustrine-swamp sedimentary environments were reconstructed on the base of the stratigraphical studies (botanical, spore and pollen, and diatom analyses and tephrostratigraphy) and radiocarbon dating of the Rasshua Island peatbogs. The relationships between climatic changes and volcanic effects during Middle/Late Holocene were analyzed. Stages of landscape evolution were distinguished, and the time of their reorganization was defined. Key words: peatbogs, Holocene, stratigraphy, climatic changes, paleolandscapes, Central Kuril Islands. A.I. Obzhirov, I.K. Pushchin, E.V. Korovitskaya Distribution of hydrogen and hydrocarbon gases in the Tonga island arc system The paper presents results of the studies on gas geochemistry of the Tonga island arc system performed by the researchers of V.I. Il’ichev Pacific Oceanological Institute (POI) FEB RAS aboard the Kallisto research vessel in 1982. The composition of oxygen, nitrogen, carbon dioxide, hydrogen, methane, ethane, and ethylene dissolved in bottom water layers and superficial sediments was investigated. High concentrations of hydrogen and hydrocarbon were found in the structures of the Tonga island arc system regardless their age and rock composition. Increased concentrations of the gases are associated with fractures including through ones which reach the oceanic slope of the Tonga trench. The authors suggest the gases in the studied region to be of a deep-seated (mantle) origin. Key words: gas geochemical testing, methane, ethane, ethylene, hydrogen, Tonga island arc system. L.F Simanenko, O.I. Sharova, S.A. Shcheka New data on titanomagnetite exsolution textures from pyroxenites of the Koksharovsky massif (Primorye) The exsolution textures in titanomagnetite grains recognized in ore pyroxenites, which belong to the first intrusive phase of the Koksharovsky massif of ultrabasic alkaline rocks, have been studied in the assumed sequence of their origin and transformation. The structural-textural pattern and compositional features of the early exsolved phases are indicative of relatively high rock cooling rates. It was shown that the composition of the studied oxide phases tend to vary with time. An initial temperature of the exsolution process in titanomagnetite was estimated to be 650–600 °С. Key words: titanomagnetite, ilmenite, exsolution textures, Koksharovsky massif. Yu.A. Mamaev, V.S. Litvintsev, V.S. Alexeev Processes of a productive layer formation of the noble metals technogene placers There were established the regularities of natural processes impact on migration and concentration of noble metals particles in technogene placer formations. Key words: technogene placer deposits, cryogenic processes, blowout piping, filtration flows, gold particles migration, productive layer formation. S.I. Levshina Manganese distribution in the surface waters of Middle and Lower Priamurye The presented data on distribution and concentrations of manganese dissolved and suspended forms in water of the Amur River and its big tributaries (Zeya, Songhua and Ussuri) were obtained in 2006 – 2009. Irregularities of manganese distribution in the Amur cross and vertical sections are found to be caused by big tributaries. Manganese organic complexes (of humus nature) in Priamurye surface waters were reported for the first time. Manganese in these complexes did not exceed 33.0 % of total dissolved manganese. Distribution of total dissolved manganese and manganese organic complexes (of humus nature) in the zone of river water mixing with sea waters of the Amur Liman is described. Key words: manganese, surface waters, a water mixing zone, organic matter, humus acids, Amur River, Priamurye. |