Геология

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 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 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.

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.

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.

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.

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.

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.

Using Palyanovskoye oil field of Krasnoleninsk arch we demonstrated that local cataclasis and pneumatolytic-hydrothermal metasomatism manifestations are widespread in the Paleozoic basement rocks. For the first time the earliest indications of deep fluid activity were detected – at the stage of granite deep fluid saturation and primary diffuse leaching of feldspars. During transition to the infiltration process, they comprise jet-stream fibroblast structures formed due to biotite and plagioclase resorption by amphibole and scapolite association.

The results bio-, magnetostratigraphic, cyclostratigraphic, lithological and mineralogic studies of the upper part of Sultanovskaya formation and Zelenogorskaya formation near v. Alexeevka (Belogorskiy region of Crimea) were presented in current work. The results of lithological and mineralogic analysis argues for the stratigraphic break between “Sultanovskaya” formation and “Zelenogorskaya” formation and implicitly indicate the age of the sediments as late berriasian.