Izvestiya of Saratov University.
ISSN 1819-7663 (Print)
ISSN 2542-1921 (Online)


Геология

On the question of the geological nature of the crystalline basement inhomogeneities of the East European Platform

Based on the analysis of gravitational and magnetic anomalies of the eastern part of the East European Platform, it is concluded that inhomogeneities caused by serpentinization processes are present in the Earth’s crust. This conclusion is confirmed by conducting geological and geophysical studies on reference objects with serpentinite outcrops.

Multi-feature petrophysical classification of rocks as a basis for interpretation of geophysical data

The work is carried out approbation of the algorithm for the complex interpretation of geophysical data using data classification algorithm. Distributions by class are obtained and compared with petrophysical materials from published sources. This data is compared and geological composition of the studied area is obtained. The applicability of this approach for the integrated interpretation of geophysical data is shown, including low-level studied areas with a complex geological structure.

Representatives of the Subfamily Cheloniceratinae Spath, 1923 (Ammonoidea)from the Aptian of Mangyshlak, Western and Southern Turkmenistan. Paper 1. General Issues. The Genus Cheloniceras Hyatt, 1900

The article presents the study results of the ammonite subfamily Cheloniceratinae Spath, 1923 representatives (genera Cheloniceras Hyatt, 1900 and Epicheloniceras Casey, 1954) fromthe Lower and Middle Aptian of Mangyshlak, Western and Southern Turkmenistan. The diversity and stratigraphic distribution of species is assessed, intraspecific variability is identified and typified. Representatives of the genus Cheloniceras are described.

Deep meridional structures of the East-European platform

Using a complex of remote and surface geophysical methods in the eastern part of the East European Platform, regional meridional heterogeneities were revealed; it is shown that these heterogeneities can be caused by low-density and magnetically active rocks in the crystalline crust and mantle. The totality of geological and geophysical data indicates the relationship of meridional heterogeneities with transcontinental deep faults.

New data on the Late Permian actinopterygian fish Toyemia Minich, a zonal genus of the Permian biostratigraphic scheme based on ichthyofauna from the Eastern Europe

The structure of the actinopterygian fish genus and speciesToyemia tverdochlebovi Minich has been completed for the first time using a previously unknown complete skeleton and skeletal fragments from Late Permian localities of Eastern Europe. The structure of a head which so far remained unknown in the genus is described. The dorsal fin location far from the head near the caudal region was confirmed as expressed earlier by the taxon’s author.

Irrigation system in the Late Cretaceous Hexactinellids (Porifera, Hexactinellida)

Within the skeletal structure of the medium- and the thick-walled Hexactinellids, the active filtration surface area was increased at expense of the elements of the irrigation system. The ostia and the transversal canal structures, the densities of their occurrences correlate with the values of the wall thickness, the skeleton habitus, the level of modular organization; they are in many ways determined by the parameters of the sponge habitats.

On the role of salty coals in kaolinite transformation into paragonite-type hydromica within the Donbass tonsteins

The character of kaolinite hydromicatization within the Donetsk Basin tonsteins in the course of metamorphism depends on the types of enclosing coals: either normal or salty ones. Alongside with terrigenous minerals within the coal-bearing masses and the fossil sea waters, indicator authigenous minerals from salty coals – halite and glauberite – should be specified as the sources of sodium and potassium for kaolinite hydromicatization.

Insoluble remains of Lower Permian sylvinite rocks in the western and north-western framing of the Caspian depression

The paper presents the results of a study of the insoluble residue of sylvinites and sylvin-halite rocks of the Lower Permian halogen formation, common within the Perelyubsky areas (Western and Eastern), promising for industrial development (Saratov Region) and the Gremyachinsky potash deposit (Volgograd Region). A technique for studying the insoluble residue of sylvinites is presented. The types of insoluble residue are distinguished according to the form of occurrence in sylvinites and its mineral composition is characterized.

The first representatives of the genus Cameroptychium Leonhard, 1897 (Porifera, Hexactinellida) from the Upper Cretaceous of the Volga region

The first representatives of Cameroptychium on the territory of Russia, which are established in the rocks of the Upper Cretaceous of the Volga region, are described. The labyrinthine structure of the skeleton and the modular, colonial level of organization of these sponges are considered, which is typical for many Late Cretaceous Hexactinellids. The widespread manifestation of isomorphism indicates the finiteness of the formation of representatives of Hexactinellida. The origin of Cameroptychium is correlated with Santonian Plocoscyphia.

Representatives of the genus Botryosella Schrammen, 1912 (Porifera, Hexactinellida) from the Upper Cretaceous of the Volga region

Among the numerous and diversiform Late Cretaceous siliceous sponges collected throughout the Volga region, several representatives of the genus Botryosella have been encountered, previously unknown for the area. Analysis of the skeleton morphology, peculiar for massive transverse outgrowths, confirms manifestations of isomorphism in Hexactinellids and the opinion of inaccuracies available in the descriptive terminology applied to the skeletal morphology of this Porifera group.

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