Геология

Widespread “camouflaged” pyroclastics including smectite, illite-smectite and heulandite are detected in the upper jurassic– lower cretaceous deposits of the Ulyanovsk-Saratov basin. Moreover, volcanic glasses are found in several stratigraphic units. The quantity of pyroclastic material in the study section (17–72%) is probably related to volcanic input in the basin.

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.

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.

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.

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.

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.

Study results of the material composition and conditions of forming P Vogulkinskaya strata of the Tolumskoye field are presented. It is established that the formation of sediments occurred in coastal-marine conditions, in the transgressive stage of the sedimentation basin development. According to the composition of the allotigenic part, the studied sandstones and siltstones correspond to the quartz, grauwack and arkose groups.

Two species of Cygnus from the Late Pleistocene deposits of Binagadi asphalt lake are described in this paper, which have not been previously known from this locality. Cygnus cygnus is represented by the left distal fragment of the radius; the right fragment of the proximal humerus and ulna belongs to Cygnus olor. Morphological analysis with recent and fossil species of the genus Cygnus makes it possible to establish taxonomic differences between species, based on certain diagnostic features that can serve as criteria for identifying species.

The article considers method application results of correlation analysis of gravitational and magnetic field data, heat flux values, data of decoding satellite images measured in the regions of the Pre-Caspian and Scythian large concentric morphological structures of the central type. As a result, using the correlation method, a complex of various geophysical fields in these regions was analyzed.

Study of the skeletal morphology of a new representative of the Leptophragmidae family, with no suboscula in its structure, provides support for the earlier specified regularities in generation of Hexactinellida modular forms. Good preservation state of a major colony has made it possible to specify the aspects of paleoecology and taphonomy in the later representatives of the Middle Coniacian – Early Santonian succession of siliceous sponges.