Volume 29, 4, 2010 |
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M.V.Goroshko, V.B. Kaplun, Yu.F. Malyshev, N.P. Romanovskiy, V.G. Gurovich.
Deep structure, magmatism and metallogeny of the Central Aldan block,
Aldan-Stanovoy shield 3 A.N. Filippov, G.I. Govorov, A.A. Chashchin, T.A. Punina. Substance composition and formation settings of siliceous-volcanogenic assemblages of the Nizhneussuriisk segment of the Kiselevka-Manoma terrain (West Sikhote-Alin) 19 V.M. Anokhin, M.E. Melnikov. Composition features of the NE slope of Govorov Guyot (Magellan Seamounts, Pacific Ocean) 34 I.Yu. Chekryzhov, V.K. Popov, A.M. Panichev, V.V. Seredin, E.V. Smirnova. New data on stratigraphy, volcanism, and zeolite mineralization of the Cenozoic Vanchinskaya depression, Primorye 45 P.L. Nevolin, V.P. Utkin, A.N. Mitrokhin. Tafuinsky granite massif (South Primorye): structures and geodynamics of longitudinal compression 64 S.V. Vysotskiy, N.G. Galkin A.V. Barkar, E.A. Chusovitin, A.A. Karabtsov. Hydrothermal precious opals of the Raduzhnoye deposit (North Primorye): the nature of opalescence 82 E.G. Ivolga. Petrophysical investigations for construction of ore district geophysical models (as exemplified by the Voznesensk ore district, Primorye) 91 Chronicles G.L. Kirillova. The problems of sediment genesis and teconics at the IV International Symposium «Paleoclimates of the Cretaceous in Asia, and their global correlation» 114 Jubilees Anatoly P. Sorokin (75th birth anniversary) 120 Alexandr V. Koloskov (75th birth anniversary) 121 M.V. Goroshko, V.B. Kaplun, Yu.F. Malyshev, N.P. Romanovskiy, V.G. Gurovich Deep structure, magmatism and metallogeny of the Central Aldan block, Aldan-Stanovoy shield Aerogeophysical and gravimetric survey data on the Central Aldan block, Aldan-Stanovoy shield, have been summarized; the map of extensiveness of Precambrian granitoid magmatism has been drawn; association of ore districts encompassing large deposits with the margins of extensive areas of Precambrian granitoids has been recognized; 3-D density modeling of this block’s lithosphere has been done; the roots of Mesozoic alkaline massifs down to a depth of 100-150 km have been traced; and the telemagmatic nature of large gold-uranium deposits related to these massifs has been defined. A.N. Filippov, G.I. Govorov, A.A. Chashchin, T.A. Punina Substance composition and formation settings of siliceous-volcanogenic assemblages of the Nizhneussuriisk segment of the Kiselevka-Manoma terrain (West Sikhote-Alin) New evidence of mineralogical-petrographical composition, genetic types of sedimentary rocks and geochemical features of effusive rocks of the Snarskiy site, Nizhneussuriisk segment of the Kiselevka-Manoma accretionary complex, developed on the right bank of the Ussuri River lower reaches is cited. The Middle Jurassic-Aptian sedimentary rocks of the site are represented by pelagic radiolarian cherts, hemipelagic siliceous mudstone deposits, insignificant shallow water limestone and volcanomictic conglomerates, and also turbidite sandstone. The basalts of the site are alkaline, resembling intraplate basalts of ocean islands, and tholeiitic, which are compared with N-MORB basalts. Assemblages of two physical-and-geographical and geodynamic settings have been distinguished: pelagic, with intraplate alkaline volcanoes and hemipelagic, with volcanic structures of spreading basalts. V.M. Anokhin, M.E. Melnikov Composition features of the NE slope of Govorov Guyot (Magellan Seamounts, Pacific Ocean) Based on comparison of photo-TV profiling data (about 4.5 thousand photos of the ocean floor have been processed) and multibeam echo sounding, structural features of the NE slope of Govorov Guyot have been investigated. The network of linear structures of this slope have been visualized. The characteristics of the direction of the linear structure network have been defined and visualized in rose diagrams. The efficiency of application of photo-TV profiling of the ocean floor for the study of the structural plan has been recognized. The surfaces of the blocks restricted by linear disturbances are characterized by difference parameters of crust type ferromanganese mineralization. This can be attributed to the tectonic factor being a major relief-forming force in the case in question, and the relief features in combination with hydrodynamic regime impose conditions within the blocks which are favorable in a different way for accumulation of Mn hydroxides. I.Yu. Chekryzhov, V.K. Popov, A.M. Panichev, V.V. Seredin, E.V. Smirnova New data on stratigraphy, volcanism, and zeolite mineralization of the Cenozoic Vanchinskaya depression, Primorye The paper presents the results of study of the Cenozoic volcanogenic-sedimentary cover of the Vanchinskaya depression of the Sikhote-Alin. We have established that regarding the composition of fossil plants, the basal part of the Cenozoic section corresponds to the Paleocene; and the overlying coal bed, to the Early Eocene. Radioisotopic dating (K-Ar method) proves that the age of the volcanic rocks intruding and overlying the coal deposits correspond to the Early Eocene: rhyolites, 44.7±1.0 Ma., and trahyandesites, 43.7±1.4 Ma. Petrographic and geochemical characteristics of effusive and volcanogenic-sedimentary rocks and related zeolitites are cited. The zeolitized rocks holding phytodetritus display an anomalously high content of yttrium and heavy rare earths. We have established that zeolitization of volcanic glass enclosed in tuffs, tuffites, and perlites was affected by hydrothermal solutions, circulating along the zones of NW faults and is genetically related to the subsurface magmatic chamber. P.L. Nevolin, V.P. Utkin, A.N. Mitrokhin Tafuinsky granite massif (South Primorye): structures and geodynamics of longitudinal compression The basis of graphical and statistical analysis of the structural geometry of the Tafuinsky Ordovician granite massif was detailed observations and mass angular measurements of its geostructural components, such as relicts of the hosting skeleton (protoliths) and their foliation, and also shadow banding, contacts of granite and aplite bodies, taxite content, etc. The pre- and syngranite types of the geostructural pattern are distinguished which formed under the external longitudinal compression. The former type is peculiar to the trajectories of the structural elements of the protoskeleton hosting the massif, and to the shadow banding of granites oriented across the compression. The latter type is characteristic of the two main phases of the massif formation: granite and aplite. It is formed by a combination of the conjugated counter-dipping thrusts and shears controlling distribution of granite and aplite substance. The same combinations quite often form also pseudo-fold structures, which are more vivid in the control of bodies of the aplite phase. Such a structural style of syngranite deformations suggests that the dynamics of their development is similar to the pregranite ones. Both pre- and syngranite geostructural patterns demonstrate that activation of external compression was of different order and impulse characterized by certain periodicity. Incidentally, long impulses of compression are clearly correlated with the stages and phases of the massif formation, when the orientation of compression at their boundaries changed twice clockwise with an angular interval of 10o. Thus, the geodynamics of longitudinal compression is regarded as the main reason responsible for the specific features of the position and architecture of the intrusive. S.V. Vysotskiy, N.G. Galkin A.V. Barkar, E.A. Chusovitin, A.A. Karabtsov Hydrothermal precious opals of the Raduzhnoye deposit (North Primorye): the nature of opalescence The results of investigation of hydrothermal precious opals are cited. Hydrothermal precious opals are recognized to differ in their nanostructure and regime of their formation from exogenic precious opals. They are made up of smaller-size globules, and they show no structuring of nanoparticles by the laws of tight packing, which is so characteristic of exogenic precious opals. In the process of formation they were subjected to pneumatolytic annealing – a high temperature vapor impact accompanied with elevated pressure. The thermal effects resulted in the formation of 2-D photon zones in the chaotic opal matrix. These photon zones were created by the grids, whose cells formed as a result of thermal effects, according to the principle of Benard cells. It was those structured blocks and thin films that result in spectral decomposition of light and iridescence. E.G. Ivolga Petrophysical investigations for construction of ore district geophysical models (as exemplified by the Voznesensk ore district, Primorye Petrophysical investigations for construction of ore district geophysical models follow two lines: 1) petrophysical completion of the physical-and-geologic model of an ore district, since the reliability of geophysical models is determined by the validity of establishing the petrophysical characteristics – physical field relationships; 2) devising petrophysical criteria of ore control and ore location. To solve the first-line tasks within the Voznesensk ore district, the following was done: petrochemical characteristics of major rock complexes of the district were defined – density (), magnetic susceptibility (), resistivity (), remnant magnetization (Іn); petrophysical contrast of rocks was studied as the basis for their mapping; petrophysical lithotypes of rocks were formulated; and possibilities of identification of physical heterogeneities based on petrophysical lithotypes were shown. The second line of investigations involved the study of the difference between the ore controlling Voznesensk granites and other granitoid complexes of the district regarding petromagnetic characteristics – , Іn, coercive force (Hcs); a possibility of mapping of hydrothermal-metasomatic changes within fluorite deposits was shown based on and rank correlation. |