V.I. Dzhurik, A.F. Drennov, A.D. Basov. The influence of structural heterogeneities of the upper part of the earth’s crust on the dynamics of seismic signals 3
V.N.Senachin, Yu.V.Pyatakov. Evaluation of influence of the spherical surface of the Earth in a two-dimensional gravity modelling 13
V. A. Bormotov, V. G. Bykov. Seismological monitoring of a deformation process 17
N.G.Shkabarnya, G.N.Shkabarnya. Methods of preliminary evaluation of oil-and-gas potential in the promising areas of Primorie Territory according to the data of electrical sounding 26

Tectonics and Geomorphology

V.P. Utkin. Horst-accretionary systems, rift-grabens and volcanic-plutonic belts of the south of the Russian Far East. Article 3. Geodynamic models of synchronous development of horst-accretionary systems and rift-grabens 35
V.S. Rozddestvenskiy, S.M. Saprygin. Structural relationships between Neogene and Quaternary deposits, active faults and seismicity on South Sakhalin 59
M.N. Shapiro, A.V. Solovyov. Structure and evolution of the Lesnaya thrust (North Kamchatka) 71

Sratigraphy and Sedimtntology

I.I.Cei, Ye.D.Kalacheva. Early Cretaceous ammonites of the Sikhote-Alin system and their biostratigraphic and biogeographical implications 83
A. V. Kurilenko, Yu. S. Bretshtein, K. S. Butin. New biostratigraphic and paleomagnetic data on the Devonian in the western Mongol-Okhotsk fold belt 93
V.V. Krapiventseva, V.G. Varnavsky, V.E. Kuznetsov. Bituminous coals and shales of the southern Far East 104

Metallogeny

L. V. Eirish, B. G. Saksin. Gold potential of the Lesser Khingan, localization patterns, and the problem of ore gold 114
I. I. Stepanov, V. M. Okrugin, R. A. Shuvalov, A. D. Ananchenko. The relationships between mercury haloes and occurrences of hydrothermal gold-silver mineralization in Kamchatka 123

Discussions
Yu.M.Pushcharovsky. Critical review of plate tectonics 131

Anniversaries
Valentin G. Moiseenko (70th birth anniversary) 134
Vladislav I. Goncharov (60th birth anniversary) 136

Index of papers published in the journal in 1999 138

V.I. Dzhurik, A.F. Drennov, A.D. Basov
The influence of structural heterogeneities of the upper part of the earth’s crust on the dynamics of seismic signals

The paper deals with the problem of influence of deep and near-surface heterogeneities on the parameters of seismic signals from earthquakes. In this case, the velocity models obtained from seismic microzoning of the sites of the Baikal-Amur Main Line, Zeya hydroelectric power plant, Bilibinsk nuclear power plant, Blagoveshсhensk heat-and-power plant, and others were applied to describe the geological medium using frequency characteristics. A correlation between the estimated frequency characteristics and those obtained from the records of local earthquakes was accomplished. The results of the study show that a differentiated approach to the evaluation of seismic hazards for the territories and individual sites is required at the stage of determination of initial seismicity. The deep and near-surface heterogeneities should be taken into account at the stage of detailed seismic zoning and microzoning.

V.N.Senachin, Yu.V.Pyatakov
Evaluation of influence of the spherical surface of the Earth in a two-dimensional gravity modelling
A computation was made for two-dimensional gravitational models on two profiles of the tectonosphere of the West-Pacific Active Margin with account of the spherical form of the Earth’s surface. The derived models were compared with the earlier computed models with no allowance made for the spherical form of the Earth’s surface.
The comparison showed that for these profiles a computation with no account taken of the spherical form of the Earth results in variations in the regional hum noise and in insignificant modifications in the determination of a density having no vital influence on modelling results.

V. A. Bormotov, V. G. Bykov
Seismological monitoring of a deformation process
A method of definition of volume deformation variations is suggested and theoretically substantiated on the basis of multiple-reflection longitudinal waves specified in the opening part of distant earthquake seismograms. The results of seismological monitoring, carried out in southern Primorie, give evidence of qualitative and quantitative differences in the deformation process depending on different deep levels. Volume deformation variations have been estimated down to a depth of 50 km.

N.G. Shkabarnya, G.N. Shkabarnya
Methods of preliminary evaluation of oil-and-gas potential in the promising areas of Primorie Territory
The regularities of change of electrical properties of rocks are examined above possible oil-and-gas deposits laterally and in depth. A technique for a tentative evaluation of oil-and-gas potential of sedimentary basins is offered on the basis of electrical resistivity definition at different levels from the surface based on the earlier electrical sounding data reinterpretation. The results of data reinterpretation within the Verhne-Bikinskaya depression are given.

V.P. Utkin
Horst-accretionary systems, rift-grabens and volcanic-plutonic belts of the south of the Russian Far East. Article 3. Geodynamic models of synchronous development of horst-accretionary systems and rift-grabens
Within the southeastern margin of Asia, NE-trending horst-accretionary systems alternating with rift-grabens are established. The synchronous formation of these both positive and negative structures occurred in the Jurassic - Early Cretaceous. Rectaduction models have been worked out within the framework of a concept of tectonic layering of the lithosphere. The models interpret geodynamically the synchronous development of rift-grabens as extension structures being favourable for occurrence of synsedimentary basite volcanism, and horst-accretionary systems as compression structures imposing basite-ultrabasite and anatectite intrusive magmatism. The supposition is substantiated that rift-grabens in the east are a continuation of latitudinal intracontinental interblock suture zones.

V.S. Rozddestvenskiy, S.M. Saprygin
Structural relationships between Neogene and Quaternary deposits, active faults and seismicity on South Sakhalin
Seismic activity on South Sakhalin is related to the zones of longitudinal faults (reverse and normal faults) of submeridional orientation separating the ridges and intermountain depressions, and NW transverse transform (sinistral) and NE (dextral) strike-slip faults. The observed system of the active faults corresponds to a stereotype of fractures resulting from sublatitudinal and diagonal (azimuth 305°) horizontal compression. In the Middle Quaternary the seismic activity shifted along the western edge of the Susunai intermountain depression from the Tym-Poronai fault crossing the Pliocene-Early Quaternary and Middle Quaternary leveling planes, to the Aprelovsky fault displacing the Lower Pleistocene and Holocene assemblages. The Lower Pleistocene deposits occur conformably with the Pliocene ones, forming a single molassic assemblage. Since paleoseismic dislocations testifying to the catastrophic Holocene earthquakes are known over the entire island territory including aseismic regions, it is necessary to study active faults over the entire area of Sakhalin Island and in the surrounding sea areas in order to determine earthquake recurrence and develop an extended-period seismic hazard forecast.

M.N. Shapiro, A.V. Solovyov
Structure and evolution of the Lesnaya Thrust (North Kamchatka)
The Lesnaya thrust exposed in the Kamchatka Isthmus is a part of a larger collisional thrust dividing the Upper Cretaceous complexes of the Achayavayam-Valaginsky paleoarc from coeval terrigenous complexes of the Northeastern Asia continental slope. The present-day thrust structure originated with the formation of deep thrusts in an allochthonous complex, whose lower nappes are composed of green schists and hyperbasite-gabbroic bodies. Blastomylonitic zones with asymmetric folds indicating westward nappe movements formed at nappe boundaries. Deformations occurred under conditions of high crustal warming inherited from the active stage of the arc development. Later these nappes together with shallower allochthon parts were exhumed and thrust onto the underwater continental margin overlain by terrigenous flysch. The autochthon complex is distinguished by small variously oriented folds forming a complicated system that indicates plastic deformation of a bedded sequence, which resulted from a slightly dominant sublatitudinal stress. Readel structures, well developed in low-temperature mylonites occurring along planes of displacement indicate northeastward movements of the allochthon parallel to the thrust front. Such kinematics is most likely to be the result of change of the northeastward thrusting by sinistral strike-slip motions at the terminal collisional stage.

I.I.Cei, Ye.D.Kalacheva
Early Cretaceous ammonites of the Sikhote-Alin system and their biostratigraphic and biogeographical implications
The paper presents a brief characteristic and data on the age and portraiture of some Early Cretaceous ammonites nominally appearing in stratigraphic schemes and works on stratigraphy of the Lower Cretaceous in the Sikhote-Alin. At the same time, a sequence of buchia assemblages is offered for the recognized stratigraphic levels. The Barremian Pseudohaploceras, for the first time identified in the Sikhote-Alin, is analogous to similar ammonites from northeastern China. The new species P. chinense has been described with allowance made for Chinese data. The character of the Early Cretaceous marine fauna of the Sikhote-Alin is examined, in which ammonite associations are represented mainly by Tethyan elements; and benthonic ones, by Boreal elements, determining an ecotone type of marine communities in the region.

A. V. Kurilenko, Yu. S. Bretshtein, K. S. Butin
New biostratigraphic and paleomagnetic data on the Devonian in the western Mongol-Okhotsk fold belt
For the first time crinoids of the Lower-Middle Lohkovian were determined in the Mongol-Okhotsk fold system. Some lithological and paleontological differences were revealed in the section of the left and right banks of the Onon River, Eastern Transbaikal region, which formerly had been related to the Makarovskaya unit of the Middle-Upper Devonian. The above-mentioned facts allow us to subdivide the Makarovskaya unit into two stratigraphic division of different age. One of them, located on the right bank, is likely to be regarded as the Makarovskaya suite of the Lower Devonian. Deposits on the left bank are considered to be a new Aratunginskaya suite of the Middle-Upper Devonian. The first preliminary paleomagnetic data have been obtained as to the Devonian in the western part of the Mongol-Okhotsk fold belt. They are confirmed by high-temperature cleanings with extraction of characteristic components. Low (near-equatorial) paleolatitudes of the terrigenous rock formation in the Devonian have been ascertained which are consistent with biogeographical data. The calculated paleopole position coincides with the trajectory of its apparent movement for the North China geoblock in the Middle Paleozoic.

V.V. Krapiventseva, V.G. Varnavsky, V.E. Kuznetsov
Bituminous coals and shales of the southern Far East
Southeastern Russia is characterized by considerable potential coal reserves. In the region under consideration, Paleogene-Neogene brown coals and Lower Cretaceous bituminous coals are well developed (Khabarovsk, Bazovsky, Mukhen coal deposits, Bureya coal field in the Khabarovsk Territory, Svobodny and Tynda deposits in the Amur Region, and Bikin, Pavlovsky coal deposits and Razdolny coal field in Primorye).
Combustible shales and bituminous limestones are widely distributed among Riphean-Cambrian sedimentary complexes in the southeastern Siberian platform (Khabarovsk Territory). They are compared with those of East China as non-traditional targets and possible hydrocarbon resources for the future power and chemical industry.

L. V. Eirish, B. G. Saksin
Gold potential of the Lesser Khingan, localization patterns, and the problem of ore gold
The paper briefly characterizes the geology and gold potential of the Sutara and Priamurie gold-bearing regions of the Jewish Autonomous Region, in which placers have been developed for over a century and ore deposits are not yet discovered. In order to obtain new data for evaluation of the region’s ore gold potential, areas have been delineated with once rich placers with poorly rounded gold, gold-quartz intergrowths, nuggets, and other ore potential indicators. The morphology of Early Paleozoic granitoid massifs has been reconstructed down to a depth of 6 km (based on geophysical data), which made it possible to infer a likely genetic link of gold potential to these granites and a zone of their endo- and exocontact with carbonaceous terrigenous-carbonate units of Riphean age. Geological study and prospecting have been recommended with reference to ore gold potential, possibly stratiform-type, of these zones.

I. I. Stepanov, V. M. Okrugin, R. A. Shuvalov, A. D. Ananchenko
The relationships between mercury haloes and occurrences of hydrothermal gold-silver mineralization in Kamchatka
The investigation of mercury distribution in several hydrothermal deposits in North and South Kamchatka shows a distinct relationship between mercury haloes and zones of hydrothermal gold-silver mineralization. All known Au-Ag ore zones with any sulfide content are accompanied by haloes of mercury. Expectedly, Hg has a high position in the Ammon’s row of vertical geochemical zoning; it can therefore help estimate the depth of the erosion level. The area of the Sergeevskoe deposit seems to have no prospects for exploration of other epithermal ore deposits. Several mercury anomalies were detected at the flanks of the Mutnovskoe and Ametistovy deposits. Some anomalies possibly reflect the position of unknown ore zones. The Rodnikovoe deposit is very local with regard to compact and contrast haloes of mercury. To ascertain the situation on its flanks, investigation of Hg distribution in the rocks and lithochemical dissipation flows in the northern and southern directions from the ore zone is required. The investigation of mercury haloes of secondary dispersion in the upper part of the volcanic ash formations with the thickness 1-2 m is useless. Since the superposed haloes of any metal in the young volcanic ash formations are absent, their sampling is useless for geochemical exploration. We recommend to continue the investigation of the lithochemical haloes of mercury as it is an effective indicator of hydrothermal-type ore deposits.

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