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The scheme of regionalization of the northern Siberian craton has principally been amended. It is proven that the succession of structural elements distinguished in the north is the same as in the south: oceanic block, pericratonic trough, and belt of intracratonic basins. Each of these structures can be, in turn, divided into several structure-facies zones. As in the south, three main stages of development have been established in the Neoproterozoic of the above structural elements, which correspond to the Mayanian, Baikalian, and Vendian.
The most considerable modifications are made in dating of the earlier established stratigraphic divisions. It is proven that the Debengda and Lower Yusmastakh Formations of the northern Siberian Platform correspond to the Kerpylian. The carbonate marker characterized by fossils of the Lakhanda Horizon plays an extremely important role in all structural elements of the northern Siberian craton. It comprises the Upper Yusmastakh, Khaipakh, Neleger, Sietachan, and somewhat more complicated Udzha Formations of the belt of intracratonic depressions; Chernaya Rechka and coeval Medvezh'ya Formations of the pericratonic trough, as well as the Kolosov and Kan'yon Formations of Taimyr. These modifications were promoted by a revision of biostratigraphy of many taxa of stromatolites and microfossils in the adjacent regions of Siberia. The microphytoliths of the Kalanchevo Complex cannot be used to determine the Baikalian and Vendian ages for the Medvezh'ya and Kolosov Formations. Thus, it was proven that the Baikalian is completely missing from northern Siberia. We argue that this is not due to the pre-Vendian erosion. Most likely, sedimentation was interrupted throughout the area by pre-Baikalian tectonic events.
The age of the oceanic volcanosedimentary and volcanogenic deposits in the Chukchi-Borzov and Zhdanov structure-facies zones is essentially refined. It is proven that they correspond to the Mayanian alone. An argument is that the wide fields made up of the island-arc volcanogenic complexes of this age are cut by narrow tabular bodies of ophiolites related to the pre-Baikalian rifting. As a result, we have corroborated the conclusion by V.E. Khain that there are two main borders of the Taimyr evolution: Grenvillian (1100 Ma) and Early Baikalian (850 Ma). We have shown that two principal events characterize the northern platform in the Neoproterozoic: formation of the supercontinent Rodinia in the Mayanian and the beginning of its breakup in the Baikalian. In the Vendian, after a large gap the superimposed troughs initiated as early as the Baikalian continued to develop.

Detailed study was given to the hydrogeology of the coal methane-promising Erunakovo region. We have established that all aquifers there are mutually related and form a single aquifer complex consisting of a series of microbeds of different water transmissivities and permeabilities. Two zones have been recognized in the Erunakovo region - of intense and slow water exchange (fresh- and brackish-water, respectively). Fresh waters with mineralization of up to 1 g/l and pH = 7-8 occur at depths down to ~300 m or, seldom, 500 m. Brackish waters have mineralization of 1-13 g/l and pH reaching 10.1. The higher mineralization is due to the higher contents of HCO₃^- and Na and, sometimes, SO₄², produced through sulfide oxidation, and Cl^-, concentrated as a result of evaporation. In the study region, CO₂ is not of mantle genesis but is the product of coal metamorphism.

We develop the electric-hydrodynamic theory of oil-water layered systems and reveal factors that allow control over the stability of these systems. Anisotropy of dielectric susceptibility, conductivity, and periodic current in a distributed system causes parametric resonance and makes the system prone to destruction.

We estimated the instrumental error introduced by logging tools into the measured plane and axisymmetrical electric fields. The problem can be solved either through investigation of analytical solutions or using integral equations. The difference between the true and the measured fields increases with frequency of electromagnetic waves and tool thickness and conductivity. The difference is lower in the case when the axisymmetrical electric field is measured by a closed loop than in the case of logging with a straight tool for the plane field. The greater the radius of the closed loop for the axisymmetrical field logging, the larger instrumental errors, the frequency being the same.

There are some reasons to publish my comments. First, the paper in question [1] is devoted to the region whose study has been my concern for a long time and, naturally, I paid attention to the manuscript as soon as it was received by Editorial Board of the journal. Second, the abstract declares important issues, which either are missing from the text body or are discussed with many errors, thus misleading the reader. Third, it is necessary to clear up what

We suggest a model of elastic rebound for the M = 7.3-7.5 Chuya earthquake of 27 September 2003 based on 3D deformation data from the Gorny Altai. We report processed data from yearly resurveyed Altai GPS stations through 2000-2004. The geodynamic network of the Institute of Geophysics (Novosibirsk) consists of 21 stations, including the Klyuchi reference station (world network code IGS-NVSK DOMES N12319 M001); it covers the structural elements of Gorny Altai and extends into the southern West Siberian plate and the West Sayan mountains. Displacement of the NVSK station in the system of permanent stations of Asia and displacement of Central Asian stations were processed to obtain a map of GPS velocities for the Gorny Altai. The velocities are in a range from 0.2 to 11 mm/yr. The velocity field shows signature of a preseismic process before the Chuya event in the southern Gorny Altai. Measurements through 2003-2004 give a pattern of postseismic deformation indicating a right-lateral strike slip in the epicentral area. The amount of displacement decreases away from the nodal plane from 300 mm at 15 km to 25 mm at 90 km far from the main shock. This regularity is explained in terms of elastic rebound in a 2D dislocation model. Modeling with the use of experimental data showed a 4MPa stress release and a 2 m displacement along the fault in the epicenter, at an average fault depth of 8 km. The shear strain related to the earthquake was estimated to be 10^-6 within 100 km away from the rupture.

We report locally nonlinear approximation algorithms for processing high-frequency induction logging data in axisymmetrical models. Forward problems for high-frequency logging are solved using the Born and Rytov approximations. Space conductivity variations in the high-frequency range change only the phase components of the electric or magnetic fields. The Rytov locally nonlinear approximation is the most accurate (1-2% error). Numerical modeling and comparison of high-frequency induction logging diagrams are applied to typical 2D models of terrigenous reservoirs.

Based on microprobe data on the contents and distribution of Cl and F in halogen-containing minerals of enclosing intrusive rocks and their hydrothermally altered varieties, the role of metasomatic processes in the balance of volatiles of the ore-forming system is discussed by the example of porphyry Cu-Mo deposits of Siberia and Mongolia. Two groups of deposits are considered: essentially copper (Erdenetiyn-Ovoo, northern Mongolia, and Aksug, Tuva), with prevailing propylitization and quartz-sericite alteration, and essentially molybdenum (Sora, Kuznetsk Alatau), with prevailing K-metasomatism (orthoclase-biotite association). All types of hydrothermal transformations lead to a drastic decrease in Cl contents in metasomatic minerals as compared with halogen-containing magmatic minerals. In chlorites and sericites, which are the most widespread in metasomatites of essentially copper deposits, no Cl and Cl-containing minerals were detected by microprobe analysis, whereas F was found in large amounts in some metasomatic minerals: secondary biotite, actinolite, chlorite, and sericite. At the studied deposits, huge volumes of enclosing rocks (hundreds of mln tons) are involved in metasomatism. The large amounts of thus released halogens (particularly Cl) might have seriously influenced the regime of volatiles during the ore formation, including the increase in the salinity of hydrothermal solutions.

First data on the U-Pb age of island-arc gabbroids and granitoids of the Dzhida Caledonide zone are presented. It has been established that these rocks formed at nearly the same time (506 ± 1 Ma, gabbroids, and 504 ± 2 Ma, granitoids) at the final stage of the evolution of ensimatic island arc. The low ⁸⁷Sr/⁸⁶Sr (0.7031-0.7033) and high positive ε _Nd (T) (+6.7...+7.6) values and localization of sample points at the same isochron evidence that the studied igneous rocks belong to the same differentiated gabbro-diorite-tonalite series, which resulted from the melting of a primary depleted mantle source with the subordinate role of a long-lived crustal component.

By the example of West Siberia, it has been shown that paleocarpology permits quite a detailed division of the continental Cenozoic of closed territories, which is unattainable by other paleontological methods. In the range from Aquitanian to Gelasian, ten biostratigraphic zones have been recognized, whose sum covers the complete stratigraphic interval of the section.