Geology
Guettardiscyphia skeletons are peculiar for thin walls and highly dense apo- and prosopores. Wall mobility was conductive to formation of conical lobate skeletons of various, occasionally geometrically regular outlines. Substantial number of fossil samples from variously composed rocks from all the Upper Cretaceous intervals has made it possible to trace skeleton transformations in sponge ontogenesis and depending on their environmental conditions.
Most of the Volga phosphate deposits are categorized as hard to recover, therefore traditional mining can result in environmental problems. An experimental rig model was manufactured for the shaftless mineral production from the thin productive layers. The projected productive capacity of a single production unit is 20,000 tons per year.
The paper deals withthe methods forstudying typomorphic featuresof clastogene quartz grains from the Melovatka suite terrigenou srocks within the stratotype and parastratotype sections. Calculated and observable typomorphic features of quartz grains have been examined; statistic analyses of their sphericity and isometricity parameter values have been made. Criteria for determining petrogenic or lithogenic nature of clastogene quartz have been specified.
During long-term operation of oil and gas fields in the groundwater on their territory are formed hydrogeochemical anomalies expressed primarily chlorellaman type chemical composition, typical of the zone of active water exchange. The formation of the chemical composition of groundwater is influenced by many factors, both natural and manmade.
Partial and complete regeneration phenomena, cases of skeleton habitus restoration have been recorded in representatives of the Late Cretaceous hexactinnelids. Regeneration incidences are in many ways associated with the ability of silicon-producing cells responsible for constructing skeleton-generating elements, spicules, to transform, to rearrange their functions in response to the changes of the organism position on the substrate surface and/or upon the changes of the aquatic environment parameters.
The paper presents the first review of the Permian and Triassic fish holotypes belonging to two classes (Sarcopterygii and Chondrich Chondrichthyes), recognized by the authors upon collecting and examining ichthyofauna bone remains from the sections within the East European Platform and the adjacent regions. Starting from the 1960-ties, 3 genera and 26 species of those fishes have been defined and used alongside with actinopterygian fishes to compile stratigraphic charts of the Permian and Triassic from European Russia and to make paleogeographic reconstructions.
The level with anomalous high values of natural remanent magnetization and Koenigsberger ratios was identify in the Upper Maastrichtian of Vol’sk depression (Saratov Volga Region). The microprobe studies of samples from this layer registered elevated concentrations of microparticles of iron, nickel, intermetallics and magnetite spherules of cosmic genesis. Similar petromagnetic anomaly was detect in the uppermost of Maastrichtian in the South Cis-Caspian (Aktolagay Plateau, Kazakhstan).
The article presents datas on the gross chemical composition of buried soils of Subatantic and Subboreal periods, that’s located on geosystems floodplain of the Middle Volga. Based on the evaluation of geochemical factors justified bioclimatic conditions of their development, as well as the peculiarities of the process of soil formation. The comparative geochemical characteristics of buried soils with their zonal analogues (leached chernozem).
The problem of Paleozoic volcanism in the southeastern Precaspian depression remains unsolved despite its relevance. Obtained by the authors results can be most adequately explained from the plate tectonics standpoint as the evidence of subduction and subsequent collision that created the Precaspian Basin southeastern framing.
The paper deals with the role of the factors that determine the texturalstructural peculiarities of potassium, potassium-magnesium and magnesium salts in the Caspian halogenic basin. Special reference is made to the role of highly concentrated brine preservation in certain basin water areas, importance of constant inflow of low condensed brine, salting-out of sodium and potassium chlorides, basin bottom morphology, the influence of two types of sedimentation rhythmicity (halogenic and terrigenous) and secondary processes of mineral formation.
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