Òîì 31, 2, 2012 |
| V.A. Guryanov, G.V. Roganov, V.N. Zelepugin, M.I. Rozinov, T.E. Saltykova.
Isotope-geochronological researches of zircons of Early
Precambrian rocks of southeastern part of the Aldan-Stanovoy shield:
new results, their geological interpretation 3 I.A. Tararin, Z.G. Badredinov, B.A. Markovsky, B.I. Slyadnev. U-Pb SHRIMP dating of zircons from metamorphic complexes of East Kamchatka 22 V.B. Kaplun. Geoelectric section of the lithosphere of the Amur-Zeya sedimentary basin along MTS profile Blagoveshchensk–Settlement of Birakan 41 A.I. Gresov, A.V. Yatsuk, A.I. Obzhirov, E.P. Razvozjaeva, G.L. Kirillova. Gasogeochemical evaluation of prospects for oil-and-gas content in the Birofeld graben, Middle Amur sedimentary basin (Far East Russia) 54 I.V. Buchko, A.A. Sorokin, V.A. Ponomarchuk, A.V. Travin, Ir.V. Buchko. The age and relation to magmatism of gold-silver mineralization of ore manifestation of the Dess-Stanovoy metallogenic zone (the North Asian craton southeastern framing) 69 N.A. Kharitonova, G.A. Chelnokov, I.V. Bragin, E.A. Vakh. Isotope composition of natural waters of the south Far East of Russia 75 V.V. Chakov. Peculiarities of distribution and characteristics of sphagnum peat deposits structure in the Lower Amur River Region 87 P.S. Belyanin, N.I. Belyanina. On the Khanka depression vegetation evolution and its mountain framing in the Late Holocene-Neopleistocene (from palynological data) 96 Chronicles A.I. Obzhirov. International scientific expedition to the Sea of Okhotsk on scientific-research vessel “Academician M.A. Lavrentiev” (cruise No 56), August 9-28, 2011 101 Reviews B.À. Voronov, P.V. Ivashov. Geoecological monitoring of the Zeya water-engineering system 103 Yu.I. Bakulin, M.T. Turbin, G.L. Krillova. Lev Isaakovich Krasny – Man, Citizen, Geologist ( to the 100th birth anniversary) 104 Memorable dates To the 100th birth anniversary of Georgiy Mikhailovich Vlasov 107 Notes for Contributors 108 V.A. Guryanov, G.V. Roganov, V.N. Zelepugin, M.I. Rozinov, T.E. Saltykova Isotope-geochronological researches of zircons of Early Precambrian rocks of southeastern part of the Aldan-Stanovoy shield: new results, their geological interpretation The results of dating of zircons of metamorphic, ultrametagenic and metamorphosed plutonic rocks of south-eastern part of the Aldan-Stanovoy shield by U-Pb method with use of the secondary ion microprobe SHRIMP-II are presented. The geological interpretation of these results is given. The obtained datings reflect in most cases not the time of rock formation, but the time of their transformations at different stages and phases of progressive and regressive metamorphism, ultrametamorphism, magmatism and tectonic dislocations. Nine generalized groups of the isotopie age values are revealed. They correspond to certain geological events that correlate with tectonic and petrological events in the western parts of the Stanovoy granite-greenstone and Aldan granulite-gneiss regions. Key words: secondary ion microprobe SHRIMP-II, Archean, aldanium, stanovium, sakhaborium, udokanium, enderbites, Avlayakan complex, Aldan-Stanovoy shield. I.A. Tararin, Z.G. Badredinov, B.A. Markovsky, B.I. Slyadnev U-Pb SHRIMP dating of zircons from metamorphic complexes of East Kamchatka The metamorphic complexes of East Kamchatka exposed within the Khavyven Highland, the Karaginsky Island, and on Kamchatka and Ozernyi Peninsulas, compose large (up to 1.5 km) elongated blocks associated spatially with the bodies of ophiolitic peridotites and gabbroids (Khavyven Highland, Karaginsky Island), or form isolated fragments and blocks among serpentinite (Ozernyi and Kamchatka peninsulas). The degree of metamorphism of the primary rocks varies from the boundary of greenschist and amphibolite facies (Karaginsky Island, Khavyven Highland) to high-pressure amphibolites facies (Ozernyi and Kamchatsky peninsulas). We have first obtained the SHRIMP zircon U-Pb data from metamorphic and magmatic rocks of the East Kamchatka complexes that testify to two time intervals of metamorphic alterations of the original rocks. The first stage of metamorphism (80–75 Ma) is coincident with formation of ophiolitic gabbro and peridotites (100–70 Ma) composing the East Kamchatka ophiolitic zone. Zones of the serpentinite , comprising blocks and fragments of high-pressure (up to 8–10 kb) metamorphic rocks caused by the rocks of ophiolite association (gabbro, basalts, tuff and siliceous deposits). They are observed on the Ozernyi and Kamchatka peninsulas. The next stage of magmatism and metamorphism encloses the time interval of 70–50 Ma. This stage is associated with formation of volcanites of tholeiite, calc-alkali, and subalkaline series, zonal gabbro-peridotite intrusions (70–60 Ma), and metamorphism of moderate pressure (up to 5–7 kb) and temperature (400–600°C), typical of the complexes of the Khavyven Highland and Karaginsky Island (55–50 Ma). According to new U-Pb zircon isotopic data, the most ancient protolith of the East Kamchatka metamorphic complexes are sedimentary-volcanogenic deposits of the Karaginsky Island (181±1.8 Ma). The age of the protolith of the Khavyven Highland is 100±11 Ma, and the age of zircons from garnet amphibolites of the Kamchatka peninsula (77.6±4.6 Ma) that corresponds to the period of the development of ophiolites of the gabbro-peridotite complex. Key words: U-Pb SHRIMP zircons age, metamorphic complex, ophiolites, East Kamchatka. V.B. Kaplun Geoelectric section of the lithosphere of the Amur-Zeya sedimentary basin along MTS profile Blagoveshchensk–Settlement of Birakan Results of magnetotelluric soundings (MTS) carried out along 350-km length profile Blagoveshchensk – Settlement of Birakan are considered. The profile makes its start in the Longjiang-Selemja orogenic belt and terminates on the Jiamusi-Bureya Massif thus northwestwardly-southeastwardly crossing the Amur-Zeya sedimentary basin in its southern part. There have been carried out 12 soundings within a broad frequency range from 1•104 to 2•10-4 Hz. The geoelectric section down to 2 and 150 km depths has been constructed, the geoelectrical parameters of the sedimentary cover of the basin have been determined and the anomalous electrical conductivity crust and upper mantle zones have been distinguished. Key words: magnetotelluric soundings, deep structure, Amur-Zeya sedimentary basin. A.I. Gresov, A.V. Yatsuk, A.I. Obzhirov, E.P. Razvozjaeva, G.L. Kirillova Gasogeochemical evaluation of prospects for oil-and-gas content in the Birofeld graben, Middle Amur sedimentary basin (Far East Russia) Results of gasogeochemical researches performed in different years in the Birofeld graben of the Middle Amur basin in combination with coal prospecting and geological-geophysical information are generalized. Data on the gas composition of a subsoil bed and snow cover, along with ground and surface waters, are given. Based on gasogeochemical and genetic indicators, hydrocarbon gases of different origin have been revealed, and basic laws governing their distribution have been established allowing preliminary evaluation of perspectives for coal, oil and gas content of the Birofeld graben. Key words: natural gases, hydrocarbon fraction, gasogeochemical indicators, genesis, coal, oil and gas content, prognosis, perspectives, East Russia. I.V. Buchko, A.A. Sorokin, V.A. Ponomarchuk, A.V. Travin, Ir.V. Buchko The age and relation to magmatism of gold-silver mineralization of ore manifestation of the Dess-Stanovoy metallogenic zone (the North Asian craton southeastern framing) The Mesozoic is associated with formation of numerous Au, Ag, Mo, and Pb ore manifestations and fields, among them the largest are the Bam, Vykhodnoy, Mogotin, Dess, Nakhodka, and others, which are part of the North Stanovoy metallogenic zone. The age of the hydrothermal and metasomatic processes accompanying mineralization correspond to 130-122 Ma that allows the ore process and formation of the Tynda-Bakaran complex (138-124 Ma) granitoids to be associated. The former compose considerable in area intrusives combined into the Stanovoy belt of the North Asian craton southeastern framing. A succession of ore objects – Au-Ag – Au – Mo(Au) has been established from south to north; the objects are confined to near-contact parts of the Stanovoy belt intrusives, the formation of which probably occurred in the transform continental margin environment. Key words: Ìî mineralization, North Stanovoy metallogenic zone, Au-Ag, North Asian craton, Stanovoy belt. N.A. Kharitonova, G.A. Chelnokov, I.V. Bragin, E.A. Vakh Isotope composition of natural waters of the southern Far East, Russia Long-term (2002-2010) extensive research on natural waters of the southern Far East of Russia have allowed characterizing distribution in them of stable and radioactive isotopes of oxygen and hydrogen. It is shown that the isotope composition of the precipitations in the southern Far East is simplified from the southern to northern areas. As compared with the atmospheric and sea waters, the region surface waters are depleted in D and 18Î, and their isotope characteristics are sensitive to insignificant seasonal fluctuations. In the region waters, a continental zonal D and 18Î distribution is established and the local meteoric line of waters is calculated. Correlations of isotopes 18Î and a deuterium in the ground waters show that they are of meteor origin, and the variations observed indicate the processes of water-rock interaction. For the first time background values of tritium (3H) in the surface waters of the region have been defined, and the time of the ground waters circulation in various hydrogeological conditions of the southern Far East is estimated. Key words: natural waters, stable isotopes, tritium, Primorye, Far East. V.V. Chakov Peculiarities of distribution and characteristics of sphagnum peat deposits in the Lower Amur River Region In this paper, the author presents data on the distribution of high peat bogs in the Lower Amur territory. The stratigraphic columns of peat deposits from some swamped areas on the Pleistocene surfaces indicating the thickness and the structure of the most typical stratigraphic sections are given. The paper considers hydrophysical and chemical properties of different types of oligotrophic weakly decomposed sphagnum peat influencing the commercial parameters of raw products. The necessity of the development of a raw material base of peat bogs of the oligotrophic type is substantiated. Key words: Holocene, peat deposit, stratigraphic column, bog peat formation processes, sphagnum moss, Priamurye. P.S. Belyanin, N.I. Belyanina On the Khanka depression vegetation evolution and its mountain framing in the Late Holocene-Neopleistocene (from palynological data) Problems of vegetation development of Late Neopleistocene – Holocene of the Khanka depression are discussed. Five phases of paleovegetation evolution are recognized in spore-pollen spectra obtained from the drill core of bottom sediments. The Riss-Wurm landscapes (Nakhodkian time - Q1III) are distinguished by plant communities of broad-leaved forests with dominating oak, and the presence of hornbeam, beech, pine, and tsuga. In the Chernorychinskian time (Q3III), the South Boreal dark coniferous taiga became widespread. The Northern Boreal vegetation containing alder and maries was widely developed on the vast areas of the region during the glacial period (Q4III) (Partizanian time). The Holocene Optimum (Q2IV) is characterized by the development of elm and oak forests with hornbeams in the Lake Khanka depression. Key words: Khanka Lake plain, paleolandscapes, Neopleistocene, Holocene |