Geology
The authors consider compositions of the rocks penetrated with the Well NO 13 in the Gremyachkinskoye sylvinite field, Volgograd Region. Varied complexes of terrigenous, ciliceous and carbonate rocks, alongside with their mixed varieties rhythmically alternate there over the Late Cretaceous, Paleogene, Neogene and Quaternary sections. Reconstructions have been made of their generation settings within marine basins; the basin evolution during that lengthy period used to be associated with periodic manifestations of tectonic events of both, global and regional scales.
The results of interpretation of biostratigraphic separation of santonian-campanian deposits of the Saratov right-bank Volga region, on the example of earlier conducted detailed and complex investigation of separation near the village Mezino-Lapshinovka have been presented. The ideas of realiability of variants of the detailed (on the level of subtages) subdivision of santonian substage in reference to the territory of the Volga right-bank have been given.
Study of the supersalt beds from the Gremyachinskoye sylvinite filed has shown the sections of both, the Permian and the Triassic beds to be curtailed relative to other areas of the Pricaspian Depression. Fragmentary parts of the Middle and of the Upper Permian beds have been revealed alongside with the Lower and the Middle Triassic, missing upper Triassic beds and the traces of the Upper Jurassic deposits.
On the basis of the analysis of the literature on studying gulling in territory of Saratov and vicinities the basic techniques and results of researches for more than 130-years period, and also directions of modern studying are noted. The modern level of a level of scrutiny gulling territories is certain.
Paleogeographic reconstructions of sedimentation settings have been substantially refined from the taphonomic data from the ichthyofauna localities; the Permian fishes from East Europe have lately acquired the orthostratigraphic status. The taphonomic research in a number of the Middle and the Late Permian ichthyofauna locations has largely confirmed the reality of existence of fairly extensive sedimentation basins over European Russia in the Kazanian, the Urzhumian and the Severodvinian ages; those basins used to be periodically connected with the World Ocean.
The mass extinction of life in the sea and on land 251 million years ago, at the Permian-Triassic boundary, was undoubtedly the largest mass extinction of all time. Sedimentological and geochemical evidence shows that global temperatures rose, that there was extensive oceanic anoxia, and that there was massive erosion of sediment, especially soils, from the land. These phenomena might have been a consequence of the massive eruptions of the Siberian Traps, which produced carbon dioxide, and greenhouse gas, as well as acid rain, which killed plants and led to stripping of soils.
Problems of modern urban drainage network functioning have been considered. Analysis of geoecological state of separate regions of urban erosive and drawn systems has been carried out. An approach to the optimization of natural and artificial drainage networks has been suggested by the example of Saratov territory.
The Gremyachinskoye sylvinite field lies in the south of the Volga monocline, to the northeast of the Severo-Kotelnikovskij overthrust. Halogen beds from the field were examined. The study has provided grounds for correlating the field potassium-bearing horizon with the Pogozhskaya rhythmic member from the Volga monocline. The halogen bed formation was influenced by the principal water area of the salt-generating basin in the east and by the calcium chloride brines discharged along the disjunctive dislocations limiting the overthrust zone.
Carbonate nodules have been examined – those forming numerous lenticular chains of diverse lengths at each hypsometric level in the Middle Jurassic deposites. Contrary to the current view of the siderite composition of the nodules, dominant calcite development is proved, with siderite and clay matter involved. The material composition of the nodules is characterized by substantial variations of the component concentrations. Inherent peculiarities of the mineral and of the chemical compositions have been revealed in each suite, alongside with specific textures.
New taxa of hexactinellid sponges: Umbrelliserus olferjevi, gen. et sp. nov. (Coeloptychiidae) from the Maastrichthyan of the Volga river basin, Russia and Turbiplana nerodenkoi, gen. et sp. nov. (Leptophragmidae) from the Cenomanian of Ukraine are described. Study of skeletal remains of the described sponges allows to confirm proposed earlier basic trends in morphogenesis of the Upper Cretaceous hexactinellids. It also is evidence of reliability of worked out principles of Cretaceous Hexactinellida systematic on a familial level.
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