Volume 26, 4, 2007 |
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V.P. Utkin, P.L. Nevolin, A.N. Mitrokhin. Late Paleozoic and Mesozoic deformation planes, and the role of structural-dynamic factors in the processes of Late Permian intrusive magmatism in Southwestern Primorye 3 V.V. Golozubov, S.V. Miklovda, Dong-Woo Lee, B.I Pavlyutkin, S.A Kasatkin. Dynamics of the formation of the Cenozoic Uglovsky Basin (South Primorye) 22 T.V. Merkulova, Ye.P. Razvozzhayeva. Application of geophysical methods for prediction of sedimentary facies in the Cenozoic grabens of the Middle Amur sedimentary basin 34 A.M. Korotky, T.A. Grebennikova. L.P. Karaulova, N.I. Belyanina. Lacustrine transgressions in the Late Cenozoic Ussuri-Khanka depression (Primorye) 53 V.V. Yershov, O.A. Melnikov. An unusual eruption of the Main Pugachevo gas-water-lithoclastic ("mud") volcano on Sakhalin in winter, 2005 69 V.K. Popov, S.O. Maksimov, A.A. Vrzhosek, V.M. Chubarov. Basaltoids and carbonatite tuffs of Ambinsky Volcano (Southwest Primorye): geology and genesis 75 V.S. Shkodzinskiy, A.I. Zaitsev. Genesis of diamonds in the light of the study of diamond characteristics dependence on kimberlite and lamproite compositions 98 Chronicles G.L. Kirillova. Topical problems of sedimentology at the 17 International Sedimentology Congress 110 Ye.V. Kislov. International Conference "Ultramafite-mafite complexes of Precambrian fold regions" on Baikal 115 V.P. Utkin, P.L. Nevolin, A.N. Mitrokhin Late Paleozoic and Mesozoic deformation planes, and the role of structural-dynamic factors in the processes of Late Permian intrusive magmatism in Southwestern Primorye Two deformation planes are established within the Southwestern Primorye, and geodynamics of their formation is recognized. The first (Late Paleozoic) plane developed under near-latitudinal compression. Submeridional systems of folding, cleavage, foliation, and zones of dynamo-thermal metamorphism normal with respect to compression were formed within the Permian strata. Also Late Proterozoic (?) basite-hyperbasites were dislocated in the same plane. Processes of granitoid magmatism occurred synchronously (Late Permian) that were controlled by fold and cleavage structures. The second (Mesozoic) plane derived by submeridional compression manifested itself in the development of NE sinistral strike-slip faults and their structural parageneses: ENE-trending systems of folds and upthrow-thrusts faults, both superimposed on the Paleozoic protostructures and occurring in their pure form in Mesozoic and Cenozoic assemblages. The conclusion is made that there was a distinct change of compression from sublatitudinal to submeridional at the Paleozoic-Mesozoic boundary, and that this change of compression, evidently, reflects the corresponding changes in the direction of lateral displacement of the adjoining Asian continent and (or) the Pacific plate. V.V. Golozubov, S.V. Miklovda, Dong-Woo Lee, B.I Pavlyutkin, S.A Kasatkin Dynamics of the formation of the Cenozoic Uglovsky Basin (South Primorye) The Uglovsky basin located in the southern part of Primorye is infilled with Eocene terrigenous, predominantly nonmarine, coal-bearing deposits. The basin is considered to be the result of syn-strike-slip extension that occurred before the Japan See opening and is related to right-lateral displacements along NNE-striking faults. T.V. Merkulova, Ye.P. Razvozzhayeva Application of geophysical methods for prediction of sedimentary facies in the Cenozoic grabens of the Middle Amur sedimentary basin The overwhelming majority of the grabens of the Middle Amur sedimentary basin (MASB) are similar in their structural characteristics typical for continental rift structures. Using models of sedimentary infilling in the well-studied rift basins, a seismofacial analysis of the grabens of MASB has been performed. Seismic facies typical for asymmetrical basins were determined, specifically on the steep slope, facies of fans; and on the gentle slope, facies of coastal shoal, alluvial plains, and deltaic fans. Seismic facies of a deep lake claimed to be potential for oil and gas source rocks were recognized. Correlation of seismic data and drilling material adds support to the correctness of the conclusions and shows that the drilled boreholes exposed deep-water lacustrine deposits of small thickness. Using VES a low-resistivity horizon which is most prospective for detection of lacustrine deposits was established in the sedimentary cover of the southwestern and eastern parts of MASB . The lowest values of specific resistance of the low-resistivity horizon (7-8 Ohm?m) are reported from the southeastern part of the basin in the 51-OK borehole area where a a borehole partially exposed a rather thick silt-clay unit. A. M. Korotky, T.A. Grebennikova. L.P. Karaulova, N.I. Belyanina Lacustrine transgressions in the Late Cenozoic Ussuri-Khanka depression (Primorye) The features of Quaternary alluvial-lacustrine and lacustrine sediment genesis in the Ussuri-Khanka depression developing in conditions of transgressive accumulation as a result of tectonic subsidence and numerous fluctuations of climate are considered. The basic role of alluvial dams and irregular accumulation is proved in the genesis of lakes within the depression. The dependence of lacustrine reservoirs level fluctuations on climatic fluctuations is shown. The new data confirming lacustrine genesis of the most part of Khanka depression section referring to the Middle Pleistocene-Holocene are adduced. Two transgressive phases with the rise of the lake level by 1.5-2.0 m above the present one for the Subboreal are established. The general conclusion is that mesorhythmicity of the sedimentary sequence fixed in the Ussuri-Khanka depression reflects its dependence on climatic fluctuations in the Late Cenozoic. V.V. Yershov, O.A. Melnikov An unusual eruption of the Main Pugachevo gas-water-lithoclastic ("mud") volcano on Sakhalin in winter, 2005 On the basis of the investigations carried out in the summer of 2005 and a large-scale (1:1000) map of the Main Pugachevo gas-water-lithoclastic volcano compiled with the help of GPS, its regular but rather unusual eruption was established. It was the largest eruption of all eruptions studied from 1911 producing an exclusively peculiar lithoclastic field of about 100 000 m2 in area extent and approximately the same volume in cubic meters from three distinct active centers of eruption beginning from a large explosion-like gas burst from one center and subsequent nonsimultaneous discharge of gas-and-water-saturated liquid lithoclastic mass from all three centers in the form of numerous heterodirectional and different in value flows. The latter did not only almost completely overlapped the plano-levelled open volcano area, but also the broad-leaved forest deeply intruded into the volcano, and they bent, overturned, broke, and sometimes pulled up and dragged for some distance several large trees. The analysis and correlation of all past registered eruptions of the Main Pugachevo gas-water-lithoclastic volcano indicates a rather different, sometimes variable character of its eruptions by many parameters: volume of the burst-out lithoclastic mass, number of eruption centers, and ratio of gaseous, liquid and solid components involved in the eruptions. Generally, the eruptions are of a pronounced multirank periodic character, more frequent (in 1 or 2 years) for low-rank relatively small eruptions, and more rare (hypothetically in 70 years) for higher-rank large eruptions. V.K. Popov, S.O. Maksimov, A.A. Vrzhosek, V.M. Chubarov Basaltoids and carbonatite tuffs of Ambinsky Volcano (Southwest Primorye): geology and genesis The paper offers the first results of petrological study of the Early Miocene basaltoids and spinel-fassaite tuffs of carbonatites from the Ambinsky volcanic structure in Southwest Primorye. The features of the Ambinsky Volcano geological structure and sections of lava and pyroclastic units composing the volcano edifice, as well as the stratified section of carbonatite tuffs are considered. The chemical composition of rocks and mineral assemblages from basaltoids and carbonatite tuffs is characterized. Compositionally, the basaltoids correspond to the non-differentiated moderately alkaline intraplate type. Petrographic features of carbonate-silicate stratification have been identified in the basaltoids and carbonatite tuffs. It is assumed that the formation of the carbonatite melt that was accompanied with simultaneous desilication with mass separation of spinel and fassaite and oversaturation of the silicate system with calcium was due to limestone assimilation with subsequent transformation of the melt structure, and liquation. The thermal decay of carbonates attended by dissolution of calcium oxide in basaltic magma and CO2 accumulation in conditions of the closed magmatic chamber resulted in the autoclave gas effect, which was responsible for heavy explosive eruptions which are not characteristic of such type of volcanic rocks. The genesis of carbonatite tuffs of Ambinsky Volcano is a model example of liquation separation of carbonate melt in the moderately alkaline non-agpaitic basaltic system. V.S. Shkodzinskiy, A.I. Zaitsev Genesis of diamonds in the light of the study of diamond characteristics dependence on kimberlite and lamproite compositions Correlation between some diamond characteristics and kimberlite and lamproite composition was established. The character of this correlation is evidence of the influence of melt viscosity on diamond characteristics and shows magma genesis of diamonds. Two genetic types of diamond crystals are distinguished - large restite ones formed during the formation of the initial kimberlite and lamproite substrates by means of slow fractionation of the peridotite layer in the magma ocean, and small early magmatic ones formed in the process of decompression-friction transformation of these kimberlite and lamproite substrates into magmas. G.L. Kirillova Topical problems of sedimentology at the 17 International Sedimentology Congress Information on the 17th International Sedimentological Congress which was held on August 27-September 1 in Fukuoka, Japan is offered. The main topics, sessions, and plans of future investigations, particularly of continental and oceanic drilling from the new Japanese drill ship "Chikyu" are covered. Ye.V. Kislov International conference "Ultramafite-mafite complexes of Precambrian fold regions" on Baikal The information about the International Conference "Ultramafite-mafite complexes of Precambrian fold regions" held on September 6-9, 2006 in the Enkhaluk settlement, Kabansky district, Buryatia Republic is presented. A brief summary of the presentations is given. |