Volume 22, 1, 2003
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Volume 22, 1, 2003 |
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T.B.Rusakova, and I.N. Kotlyar.Geochronology of granitoid intrusion complexes of the Main Kolyma Batholith Belt (Northeastern Russia) 3
Yu.D. Markov, A.V. Mozherovsky, A.N.Derkachev, I.V. Utkin, N.A.Sereda, N.N. Barinov. The origin problem of the Fe-rich layered silicates in sediments of the Japan Sea island shelf 18
L. A. Izosov. Middle Paleozoic evolution and metallogenic features of the Japan Sea continent-îcean transitional zone 37
O.V. Dudarev, A.I. Botsul, I.P. Semiletov, A.N. Charkin. Modern sedimentation within the near-coastal shelf cryolitic zone of the Dmitriy Laptev Strait of the East Siberian Sea 51
P.F. Volgin, V.I. Isaev, V.Yu. Kosygin. Oil and gas potential of the Upper Cretaceous deposits, Southern Sakhalin 61
Yu.S. Bretshtein, Yu.D. Zakharov, A.V. Klimova. Paleomagnetic study of Triassic deposits in Southern Primorye (preliminary results) 71
L.L. Petukhova, V.S. Prikhodko, V.M. Chubarov. Comparative mineralogy of Late Cenozoic alkali basaltoids, Western and Eastern Sikhote-Alin 83
S.V. Rasskazov, E.V. Saranina, Yu.A. Martynov, A.A. Chashchin, S.O. Maksimov, I.S. Brandt, S.B. Brandt, M.N. Maslovskaya, S.V. Kovalenko. Evolution of Late Cenozoic magmatism at the active continental margin of Southern Primorye 92
Obituary
L.P. Karsakov (1935–2002) 110
Notes for Contributors 111
T.B.Rusakova, and I.N. Kotlyar
Geochronology of granitoid intrusion complexes of the Main Kolyma Batholith Belt (Northeastern Russia)
The Middle Jurassic age of the Nera-Bokhapchinskiy, Basugun’inskiy and Kolyma intrusion complexes composing the Main Kolyma Batholith Belt has been proved on the basis of analyses of isotopic data (Rb-Sr, K-Ar, 40Ar/39Ar, U-Pb-methods) and geological relationships. It is demonstrated that isotopic systems of granitoids were repeatedly disturbed during the process of gold-rare metal, gold-quartz, and tin ore formation, and during emplacement of late intrusions. A new methodological approach to isotopic data interpretation is suggested.
Yu.D. Markov, A.V. Mozherovsky, A.N.Derkachev, I.V. Utkin, N.A.Sereda, N.N. Barinov
The origin problem of the Fe-rich layered silicates in sediments of the Japan Sea island shelf
Fe-rich layered silicates in sediments of the Japan Sea island shelf were investigated. Their mineral and chemical compositions were determined, and correlation of glauconite with bedrock from the islands was made. The genetic differentials have been distinguished: a) clays fragments compositionally corresponding to smectite, which resulted from the break-up of poorly lithified rocks; b) roundish grains (dark green and black) compositionally close to celadonite, which formed, apparently, in the pores and interstices of volcanogenic rocks; c) foraminifera moulds; d) inclusions in cavities of volcanic glass. The predominant part of these species (up to 97 %) are relict, allothigenic. They have appeared in the shelf sediments as a result of destruction of poorly lithified “green tuff” rocks widespread in the coastal area. Only a minor part of clays debris, foraminifera moulds and inclusions in the volcanic glass cavities are formed in situ in the shelf sediments. They have a sedimentary and diagenetic authigenic origin.
L. A. Izosov
Middle Paleozoic evolution and metallogenic features of the Japan Sea continent-îcean transitional zone
This paper offers for the first time correlation of Middle Paleozoic deposits conducted by the formational method at the V.I. Ilyichev Pacific Oceanology Institute, Far East Branch of the Russian Academy of Sciences (Vladivostok), for the Japan Sea Region. It is shown that riftogenic processes widely occurred within the study fragment of the East Asia continent-ocean transitional zone. The Middle Paleozoic formations accumulated in the sea and îceanic basins and fill rifts, diwa structures and amagmatic platform troughs. They are closely related in the lateral direction and form series of tectonic complexes, which are characterized by transitional types. The regionally essential problem of discrimination of monotypic Middle Paleozoic and Mesozoic “barren” (lacking fossils) siliceous-carbonate-volcanogenic-terrigenous formations, often distinguished by a chaotic structure, is discussed. The metallogenic features of the Middle Paleozoic formations of the Japan Sea region imply that in many cases these formations are ore-bearing and potentially ore-bearing (U, Th, Pb, Zn, stratiform pyrite ore, diamonds, etc.). The Middle Paleozoic formations are presumed to be the source of ore matter for the regionally known commercial pyrite stratiform deposits and ore occurrences, which are the ore-bearing olistostromes. The processes of formation of the Japan Sea transitional zone megastructure are considered basing on the paradigm of the lithosphere tectonic stratification.
O.V. Dudarev, A.I. Botsul, I.P. Semiletov, A.N. Charkin
Modern sedimentation within the near-coastal shelf cryolitic zone of the Dmitriy Laptev Strait of the East Siberian Sea
On the basis of two-year observations, both sediment forming processes and relief forming processes have been studied within the cryolithozone of the Dmitiry Laptev Strait during the iceless periods. A latitudinal circumterral structure has been established of the distribution of the suspended matter and bottom sediments (it is parallel with the coastal line and isobaths). This structure is a reflection of the interaction between water circulation and the bottom relief; the latter determining the location of the areas erosion, transit, accumulation and formation of small-scale barrier zones.
P.F. Volgin, V.I. Isaev, V.Yu. Kosygin
Oil and gas potential of the Upper Cretaceous deposits, Southern Sakhalin
An assessment was made of the oil and gas potential characteristics of the area encompassing Upper Cretaceous deposits in the southern part of the Central Sakhalin Fault at an altitude of the City of Yuzhno-Sakhalinsk. Geodensity modeling, paleotectonic reconstructions, and paleotemperature modeling were employed as an investigation method. Distribution sketch maps of the absolute values of density of the Upper Cretaceous deposits and Meso-Paleozoic basement were constructed. An anomalously deconsolidated zone was discriminated that adjoins the Central Sakhalin Fault. It is identified with a high-permeability area of the Earth’s crust, and units-collectors of fracture-pore type. Distribution sketch maps of paleotemperatures for the roof and base of the Upper Cretaceous deposits were constructed. Basing on the katagenetic zoning of the phase state, early katagenetic gas pools can be suggested in the upper part of the deposits in the eastern part of the area; and oil accumulation, on the west. In the lower part of the deposits, oil accumulation is inferred as a narrow strip; and in the central and western parts, gas and gas condensate pools are presumed. The areas most promising for search for commercial oil and gas are predicted along the Central Sakhalin Fault zone.
Yu.S. Bretshtein, Yu.D. Zakharov, A.V. Klimova
Paleomagnetic study of Triassic deposits in Southern Primorye (preliminary results)
Reconnaissance paleomagnetic investigations of Early Triassic terrigenous complexes in the four sections of Southern Primorye have been conducted. They are comparable with the previous results for other Triassic structures, and also with biostratigraphic data. Petromagnetic characteristics have been studied, specifically the parameters of magnetic anisotropy. They give evidence of the absence of substantial postsedimentary tectonic deformations, which influenced the character of distribution of magnetization. The available paleomagnetic data have been proved by high-temperature gradual thermal demagnetization with employment of component analysis and modern graphic and analytical test methods, which involve the distinguishing of In characteristic components and the defining of their nature. A spread of definitions for individual geological sections has been established, which is due to the possible presence of the In syn- and postfolding components. The calculated paleomagnetic pole for the Triassic in Southern Primorye is located at the crossing of trends of the apparent paleopole migration for the Siberian and North China platforms and is close to the position of the present-day geomagnetic pole.
L.L. Petukhova, V.S. Prikhodko, V.M. Chubarov
Comparative mineralogy of Late Cenozoic alkali basaltoids, Western and Eastern Sikhote-Alin
The paper offers the results of the comparative study of mineralogy of Late Cenozoic alkali basaltoids from volcanic structures forming extended belts within the Western and Eastern Sikhote-Alin. Differences have been recognized in the mineral parageneses of impregnations and groundmass between the volcanics of these belts, and also distinctions in the chemical compositions of the minerals composing them. Crystallization conditions for alkali basaltoids are considered. It is shown that crystallization of alkali basaltoid melts in the Eastern belt began near the crust-upper mantle boundary; and in the Western belt, melt crystallization occurred at relatively small depths. It is presumed that the geodynamic regime of the Earth’s interior was the main factor governing the course of crystallization of magmatic liquids within the Late Cenozoic basaltoid belts.
S.V. Rasskazov, E.V. Saranina, Yu.A. Martynov, A.A. Chashchin, S.O. Maksimov, I.S. Brandt, S.B. Brandt, M.N. Maslovskaya, S.V. Kovalenko
Evolution of Late Cenozoic magmatism at the active continental margin of Southern Primorye
In the Late Cenozoic volcanic fields of the active continental margin in Southern Primorye, lava sequences have been studied, K-Ar dating has been performed, trace element concentrations have been determined by ICP-MS technique, and strontium isotopic ratios have been measured. In magmatic evolution, three time intervals are distinguished: 1) eruptions of andesite basalts at 14-13 Myr, 2) eruptions of low-K tholeiitic basalts, andesitic basalts, andesites, olivine tholeiites and megaplagiophyric basalts at 12 to 8 Myr, and 3) extrusions of minor bodies of olivine tholeiites and basanites with deep-seated inclusions at 8-3 Myr. In terms of strontium isotopic ratios and trace element concentrations in the volcanic rocks, magmatic sources from the asthenosphere, lithospheric mantle and crust are recognized. A lateral change of enriched mantle sources within the Arsenyev terrane zone of the Precambrian Khanka massif by depleted sources within the Samarka terrane accreted to it in the Middle-Late Jurassic is defined.