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The geologic structure and lithology of the Sobolev kimberlite pipe and some other nearby pipes are considered. These pipes are buried beneath Upper Paleozoic terrigenous-sedimentary rocks intruded by trap sills. The total thickness of the overlying rocks reaches 80 m. The pipe kimberlites belong to a magnesian group. They are composed of autolithic breccias typical of kimberlites of the Alakit-Markha field and have a low diamond potential. In addition to indicator minerals, the heavy fraction of kimberlites has elevated contents of almandine and ferriferous ilmenite, which were transported from schists of the platform basement.Despite the low diamond potential, the kimberlites often bear not only magnesian garnets and chromites but also subcalcic knorringite-containing pyropes and chromites of diamond association. This is a typomorphic feature of garnets and chromites of kimberlites of the Daldyn-Alakit region.

Using a modern microprobe, we have thoroughly studied the structure and phase composition of polymictic rims on picroilmenites sampled from modern alluvial deposits and from eluvium of the Khorkich pipe in the Taigikun-Nemba kimberlite field. Data obtained helped to refine the composition and genesis of similar rims. We have established that their formation was a long process, which included both reactionary replacement of picroilmenite by neogenic mineral phases at the magmatic stage as a result of the long-term interaction of its grains with kimberlitic melt and the subsequent postmagmatic replacement (corrosion) of these phases by secondary minerals. At the magmatic stage, perovskite and titanomagnetite were the major minerals that developed after the picroilmenite grains. At the postmagmatic stage, both picroilmenite and neogenic mineral phases were replaced by leucoxene and serpentine. The formed surfaces are primary in the context of the processes of formation of heavy-concentrate aureoles, and the relief itself is more correct to be called reactionary-corrosive. We suggested that the development of a rather intensive reactionary-corrosive relief on picroilmenites can exert a negative effect on the diamond potential of kimberlite bodies.

Lichens are widespread in the vegetative cover of West Siberia, particularly in its north, where they serve as one of the links of the natives' food chain. They play an important role in the migration and transformation of chemical pollutants. This paper presents results of studying the effect of some factors on the accumulation of chemical elements in the lichen cover.Throughout the study area, lichens have background average contents of trace elements close to those in the Arctic regions of Eurasia. Elevated contents have been established only for Cd and Mn in the Altai Territory and for Pb and Cr throughout the West Siberian region. We studied the ratios of concentrations of man-induced radionuclides (¹³⁷Cs, ⁹⁰Sr, ^238,239,240Pu) and trace elements (Cd, Pb, Cu, Zn, Mn, Cr, Ni, Co, Hg) in the upper and basal parts of the lichen and in the underlying soil substrate. The average specific activity of ¹³⁷Cs in the lichen cover of northern West Siberia is higher than that in southern West Siberia - 153 and 44 Bq/kg, respectively.

Theoretical probability of resonance is tested against experimental seismic measurements in a layer of frozen coarse sediments overlying frozen bedrock. Resonance frequencies are estimated relative to the frequencies of P and S waves from 14 earthquakes recorded at three stations. P and S velocities in the sediments are predicted proceeding from the equality of resonance frequency/velocity ratios using integrate values of water content- and temperature-dependent velocities in sedimentary frozen ground in the Baikal and Transbaikal regions. Thus seismic velocities in unconsolidated sediments can be predicted from earthquake records using integrate laboratory and field velocity data.

It is suggested to use indirect information in machine contouring by means of power potential polynomials as a basic geometrical tool. Unlike other methods, the problem in the new approach is formulated in terms of an information-geometric model free from the mechanical analogies. Interpolation of scattered data does not require approximating procedures, and the basis functions intrinsically minimize the complexity of the contoured surfaces. This allows avoiding labor-consuming explicit variational solutions to ill-posed problems. The new algorithm was successfully used in structural mapping of buried surfaces.

Signature of main latest Late Glacial (Sartan) geological events within West Siberia is found in sections of exposed fluvial sediments in the Ob' valley floor near Surgut.

We compared stages of the taxonomic restructurings that occurred in communities of ammonites, belemnites, and bivalves in Siberian sea basins in the second half of the Early Jurassic and at the beginning of the Middle Jurassic. In general, the main stages are similar in different groups of mollusks, but the restructuring borders often do not coincide. Degree of endemism and portion of immigrants in communities of different groups differ as well. Abiotic factors that have an effect on the evolution and migration are addressed here. On the basis of areal differentiation of mollusk assemblages, three paleobiogeographic areas have been recognized since the Late Pliensbachian: circumpolar Arctic, western Boreal-Atlantic and eastern Boreal-Pacific Realms. These realms are united into the Panboreal Superrealm. Ammonite, belemnite, and bivalve zonal scales devised for the Siberian Jurassic reflect the specific evolution of each of these groups in seas of the Arctic Realm as well as specific variations in its communication with adjacent realms.

Data on stratigraphy of Carboniferous and Permian deposits formed in marginal seas of Angarida, which is the ancient Siberian continent covering the territory of Siberia and Far East, have been generalized. The biostratigraphic base of interregional correlation consists of: zonal faunal complexes of the key Verkhoyansk-Okhotsk region, nine key correlation intervals, and six event borders. The most important event levels were soles of transgression-regression cycles corresponding to mass extinction of biota, innovation, immigration of new communities, change of dominants, etc. The most drastic changes in paleogeography of marginal seas of Angarida and composition of faunal communities are related to the Tournaisian-Visean Shcheglov and Middle Bashkirian Tylakh events. Geodynamically oriented paleogeographic flow charts have been compiled for three time sections (Late Tournaisian, border of Early and Middle Carboniferous, beginning of the Early Permian).

New neotectonic data from the southwestern periphery of the Siberian craton reveal post-Miocene reverse thrusting in the zone of the Alar'-Belaya fault. Traces of activity were found in Late Pleistocene-Holocene sections in the lower reaches of the Belaya River and on the left bank of the Angara as seismogenic rupture in sediments produced by local and remote shocks.

During the formation of intraplate volcanic ridges the hot upper mantle controls the decompression melting of ascending low-density upper-mantle material above hot spots. Depending on the degree to which the upper mantle is warmed up, the extent and dynamics of partial melting as well as the dimensions of the asthenosphere can considerably differ: (1) The time of existence of a zone of partial melting varies from 15 to 90 Myr; (2) the maximum degree of partial melting may differ by a factor of 5-10 (from 5-7 to 50-60 vol.%); (3) horizontal dimensions of the asthenosphere may change from 150-200 to 400-500 km.
Depending on given conditions, such parameters as melting depth, asthenosphere thickness, and position of the upper solidus boundary can considerably change with time. Our calculations show that the ultimate depths of the upper solidus boundary is about 100 km. It is unlikely that any standard (in composition of magmas and extent of melting) types of plume-related magmatic systems existed in the geological past. Given no initial conditions in the upper mantle, the dynamics of hot spots can be inferred from geochemical characteristics of magmas rather than from temperature and size of hot spots.