Contents

Tectonics
S.M.Sinitsa. Paradox of cleavage    3
M.V.Alexyutin, S.D.Sokolov. Paleomagnetic researches in the Penzhin-Taigonos part of the Pacific belt: results and their tectonic interpretation    13
Sedimentology and stratigraphy
A.M.Korotky, N.G.Razjigaeva, T.A.Grebennikova, L.A.Ganzey, L.M.Mokhova, V.B.Bazarova, L.D.Sulerzhitsky. Holocene marine terraces of Kunashir Island    28
E.S.Panasenko, V.S.Rudenko . On possible division of the monotonous siliceous deposits on the ratio of rock-forming microfossils in the instance of the Sikhote-Alin bedded chert     46
I.V. Kemkin, R.A.Kemkina. Jurassic-Early Cretaceous biostratigraphy of cherty and terrigenous deposits of Dalnegorsk ore area (Southern Sikhote-Alin)    59
S.V. Zyabrev. A stratigraphic record of the cherty-terrigenous complex in the Khekhtsyr range, and kinematics of asymmetric folds – indicators of subduction accretion     76
Magmatism and geochemistry
I.N. Govorov, E.D. Golubeva. Association of alkalic and subalkic basalts of the Pacific Ocean and their petrogenetic nature    85
L.N.Khetchikov, V.A.Pakhomova, V.I. Gvozdev, D.Z.Zhuravlev, N.S.Gerasimov. Rb-Sr isotope age and fluid regime peculiarities of granitoid formation of the Lermontovsky skarn-sheelite deposit (Primorye)    99
Metallogeny
V.A.Pristavko, V.I.Goncharov, A.A.Sidorov. Systematization and evaluation of silver occurrences and deposits of the Okhotsk-Chukchi volcanic belt by geologic and geochemical data    109
A.A.Cherepanov, G.G. Arkhipov. Stratiform fluorspar mineralization in the south-eastern Siberian platform    117
Mathematic methods in geology
O.A.Kislovsky, V.I.Isayev. The conceptual model of the State Far Eastern Regional Bank of Digital Geological-Geophysical Information on Oil and Gas    131
Discussion
Ch.B.Borukaev. And again on terranes    141
Anniversaries
N.A.Shilo (to the 85-th birth anniversary)    143
Notes for Contributors    144

S.M.Sinitsa
Paradox of cleavage
Based on the original data and published information, the author discusses the problem of tectonic cleavage formation. It is concluded that the cleavage is resulted from inhomogeneity of the tectonic deformation.

M.V.Alexyutin, S.D.Sokolov
Paleomagnetic researches in the Penzhin-Taigonos part of the Pacific belt: results and their tectonic interpretation
Island arcs serve as indicators of the convergent boundaries of the lithospheric plates, and their investigation is of high importance for paleomagnetic reconstructions. The present paper deals with some results on the paleomagnetic investigation of the complexes (Late Paleozoic-Early Cretaceous) from different structures of the Udsk-Murgal island-arc system. It is shown that the studied rocks were re-magnetized at different deformation stages. The tectonic interpretation of the obtained results regarding to the regional geological data is also presented. The formation of the studied structures is considered to be the result of the North America and Siberian plates interaction during the Atlantic Ocean opening.

A.M.Korotky, N.G.Razjigaeva, T.A.Grebennikova, L.A.Ganzey, L.M.Mokhova,
V.B.Bazarova, L.D.Sulerzhitsky
Holocene marine terraces of Kunashir Island
Holocene terrace sequence of Kunashir Island includes some levels: 5-6 (III), 3-4 (II) and 2-3 (I) m, that were formed during different Flandrian Transgression phases. A sea- level rise in the Atlantic phase led to the formation of large barrier forms with lakes within the brasion-inlet coasts (terrace III). There were paleostraits within the Sernovodsky and Kruglovsky Isthmuses, large inlets and lagoons within the South Kuril Isthmus. Mixed forests with fir, spruce and broad-leaved taxa were developed on the island. Terrace II and I were formed in the Subboreal and Subatlantic. Fir-spruce forests with fine-leaved taxa occupied the island in a Late Holocene. Correlation of the roof of marine units from the low marine terrace sections reflects sea level variations during the Middle-Late Holocene and indicates their weak tectonic deformation.

E.S. Panasenko, V.S.Rudenko
On possible division of the monotonous siliceous deposits on the ratio of rock-forming microfossils in the instance of the Sikhote-Aline bedded chert.
In addition to a traditional biostratigraphic method of monotonous siliceous rocks division, another one was suggested to divide by the biotic events, reflected in the generalized characteristics of the siliceous microfossil taphocoenousis. These characteristics concern a high rank taxa ratio and evolution of main groups of radiolaria and siliceous sponges. The following three types of cherts: sponge and radiolaria-bearing chert, spumellaria-bearing chert and follicucullus-bearing chert, were distinguished by the dominated rock-forming group of organisms. The distinguished cherts were correlated to the radiolaria zonal scale of the Permian Sikhote-Alin and to the magnetostratigraphic scale as well. All that enabled us to evaluate the relative significance of the events, resulted in the change of facies and lithologic characteristics. The method suggested here should be very useful for the stratigraphy when microfauna is poorly preserved and distinguishing of either genus or species is impossible.

I.V. Kemkin, R.A.Kemkina
Jurassic-Early Cretaceous biostratigraphy of cherty and terrigenous deposits of Dalnegorsk Ore area (Southern Sikhote-Alin)
The data of cherty and terrigenous deposits biostratigraphic researches of Dalnegorsk Ore area are summarized in this paper. Twelve consistently changing each other radiolarian assemblages are distinguished. They characterize Upper Pliensbachian-Lower Toarchian, Lower-Middle Toarchian, Upper Toarchian-Middle Aalenian, Upper Aalenian-Lower Bajocian, Middle Bajocian, Upper Bajocian-Lower Bathonian, Middle Bathonian-Lower Callovian, Middle Oxfordian-Lower Kimmeridgian, Middle-Upper Kimmeridgian, Lower-Middle Tithonian, Upper Tithonian and Lower Valanginian-Lower Barremian deposits of a single cross-section. Brief characteristics of radiolarian assemblages and photos of the Jurassic-Early Cretaceous radiolarians are given.

S.V. Zyabrev
A stratigraphic record of the cherty-terrigenous complex in the Khekhtsyr range, and kinematics of asymmetric folds – indicators of subduction accretion
The research addresses the restoring of evolution of a subduction complex in the Khekhtsyr Range near the city of Khabarovsk (Russian Far East). A prominent feature of this south-easternmost part of the Badzhal accretionary wedge terrane is slab imbrication and folding. Stratigraphic record documented an oceanic plate travelling from a remote ocean to a convergent margin. Oceanic and continental margin deposits were incorporated into the accretionary wedge during the westward subduction, according to kinematics of the earliest mesoscopic asymmetric folds.

I.N. Govorov, E.D. Golubeva
Association of alkalic and subalkalic basalts of the Pacific Ocean and their petrogenetic nature
The paper presents a discussion of the specific features of petrography, petrochemistry, and geochemistry of associations of subalkalic and alkalic basalts, titanium tholeiites of the Pacific Ocean island chains- Hawaiian, Southern (Australian), Society, and Samoa related to Cenozoic intraplate magmatism. Rocks with sodic type alkalinity and moderately high titanium content (the Hawaiian type) predominate; associations with the potassic type alkalinity (Marquesas, Cross-Line, and Samoa Provinces) and tholeiite-alkali-basaltic associations with ultrahigh titanium content (the Samoa type) have also been revealed. These petrochemical features suggest new mechanisms of mantle metasomatosis and the influence of the initial substratum composition on the formation of different tholeiite-alkalic-basaltic associations.

L.N. Khetchikov , V.A. Pakhomova , V.I. Gvozdev , D.Z. Zhuravlev, N.S.Gerasimov
Rb-Sr isotope age and fluid regime peculiarities of granitoid formation of the Lermontovsky skarn-sheelite deposit (Primorye)
Rb/Sr isotope systems in granitoids of small Lermontovsky stock and large Shivkinsky massif were studied.
It was determined that these massives are nearly of the same age (isotope age is 125 - 127 Ma), and constituting rocks are characterized by practically equal initial Sr-isotope ratios . According to the isotope data,sialic material played a significant role in the original granite melt formation.
Inclusions of mineral-forming media in granite quartz were studied. Stock rocks and massif rocks are distinguished by the amount of fluid inclusions, their types, and phase ratios, that is due to distinctions in geodynamic envvironment of the intrusions formation process. Specific features of heterogenous transformation of melts under different geodynamic environments of the intrusion formation, that affected accumulation or dispersion of ore components are tracing due to quarttz inclusions. General features and differences in fluid composition preserved in the inclusions and influence of the country rocks are recorded.

V.A.Pristavko, V.I.Goncharov, A.A.Sidorov
Systematization and evaluation of silver occurrences and deposits of the Okhotsk-Chukchi volcanic belt by geologic and geochemical data

About 200 mineral occurrences and deposits within the Okhotsk-Chukchi volcanic belt and around it were evaluated by the obtained geological and geochemical data. They include gold-silver, silver-polymetallic,tin-silver and gold lode deposits. Geochemical and mineralogical data on the ore bodies and altered host rocks were recognized as the best indicators of different deposit types among 289 descriptive regional and local criteria. The whole set of indicators obtained for each known mineral deposit in the area of study served as a basis to establish comprehensive mineralogical and geochemical criteria indicating the ore deposit assemblage and to evaluate gold-silver mineralization there. All geological targets under consideration are divided into 7 groups, which have been systematized by the authors and form a single ore deposit series. Among gold-silver deposits are distinguished several subgroups in terms of their reserves and ore grades, and they range from high-commercial to low-commercial ones.

A.A.Cherepanov, G.G. Arkhipov
Stratiform fluorspar mineralization in the south-eastern Siberian platform
Fluorspar mineralization in the carbonaceous rocks of the southeastern part of the Siberian platform was formed due to mobilization and re-distribution of the primary sedimentary fluorspar in the process of the regional dynamometamorphizm and hydrothermal activity during the tectono-magmatic activization stage. Fluorspar accumulation in sediments is closely associated with terrigenous-sedimentary rocks of dolomite series deposited in shallow-water shelf zones of the barrier lagoon under conditions of the arid climate. Revealing and insulation of the fluorspar as bedded and other forms produced at the diagenetic stage. During this stage horizons, beds, layers enriched by fluorspar were generated. Re-distribution of fluorspar was originated under the influence of the tectono- magmatic activization process. The results of this process were generation of the economic ore bodies both concordant and discordant ones. Fluorspar deposits of the Siberian platform are small in size, but they are characterized by very high quality. They are located in the developed region of South Yakutia, that affords to explore and develop them commercially in short time and with minimum expenses.

O.A.Kislovsky, V.I.Isayev
The conceptual model of the State Far Eastern Regional Bank of Digital Geological-Geophysical Information on oil and gas
Within the framework of projecting the State Bank of Digital Geological Information, work is carried out on setting up the Far Eastern regional bank of oil specialization. It is implemented by the Dalinformgeocentre disposing of topical achieve and fund materials of geological exploration on the Far East areas promising for oil and gas. The conducted work is aimed at preserving and efficiently using geoinformation on the basis of geoinformational systems technologies, commercial data base control systems and network regime of export-import of information. A conceptual model of the system of computer data bases was worked out; volumes of retrospective information were assessed and stages of the work were determined until the beginning of 2000.