Geology

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.

A new locality of chondrichthyan fishes from the Upper Paleocene on the right bank of the Don river (Volgograd region)

An assemblage of chondrichthyans is described from the new locality near Serafimovich town (the western part of Volgograd region). More than 2500 fossils were collected from the basal gravel-pebble bed and phosphorite-bearing layer from the lower part of the Buzinovka formation (upper Paleocene). There are reworked Cretaceous and Paleocene chondrichthyans (6 species) and synchronous 21 species of sharks and 2 species of chimaeroids.

Nannopterygius finds in the West Kazakhstan region of the Republic of Kazakhstan

This article describes the skeletal fragments of new species of ichthyosaurus Nannopterygius mikhailovi sp. nov. and Nannopterygius yakimenkae sp. nov. from the Upper Volga sublayer of the Upper Jurassic of the West Kazakhstan region of the Republic of Kazakhstan (Shchuchkino section). The species are assigned to the genus Nannopterygius.

Results of the reconnaissance magnetostratigraphic studies of Paleocene in the southern part of the Saratov right bank

The results of rock-magnetic and paleomagnetic studies of two sections of the Lower Syzran subformation (Paleocene) of the Saratov Right Bank – the Syrt Mountain (Nizhnyaya Bannovka village) and Lysaya Gora (Saratov city) are presented. For the first time the possibility of obtaining paleomagnetic data on the Paleocene of the Volga region and their use for magnetostratigraphic purposes despite the partial remagnetization of rocks has been established.

Natural conditions of the Popigai diamond deposit (North-West Yakutia)

The article highlights the features of the diamond mining industry in Yakutia. The history of the discovery and study of impact diamonds Popigai deposit formed as a result of the penetration of the eponumous huge meteorite into the rock mass are traced. Some features of Popigai crystals and the prospects of their use in various sectors of the national economy of the country are characterized.

Conditions for the formation of deposits in the upper part of the Berriasian section near v. Alekseevka, Belogorsk region, Republic of Crimea

The results of the paleoecological analysis on ostracods of the upper part of Sultanovskaya Formation (Boissieri zone) in the section near v. Alekseevka are presented. Five ostracod assemblages reflecting changing conditions in the paleobasin are defined. It was established that the sedimentation in the Late Berriasian time occurred under conditions of a warm normally salty with a calm hydrodynamic regime of the basin, mainly in oxygen waters.

Pseudoderivations of Paracraticularia cylindrica (Michelin, 1840) (Porifera, Hexactinellida)

The morphological diversity of diosculumic sponges, known as Paracraticularia cylindrical, results from the fact that many fossils assigned to this species prove to be fragments of the apical segments of internodes (branches) from major colonies that are rarely encountered as totally preserved fossils. The structures of the branch apical segments and the oscula outlines reflect various manifestations of hexactinellida synchronous division conductive to morphological diversity of the descendants, the succeeding complicatedly structured colonial sponges.

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