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


Genus Sororistirps (Porifera, Hexactinellida, Ventriculitidae)

Representatives of the genus Sororistirps, distinguished among the Ventriculites, have been detected in the Santonian – Maastrichtian rocks from the southeast of the Russian Plate. The structures of the skeletons and of the irrigation systems have been considered, the Sororistirps morphogenesis has been traced; the forms characteristic of the Santonian, Campanian and Maastrichtian spongiocomplexes have been determined.

The Late Cretaceous Lithofacies of the Bottom Volga Region

The distinctions of the late cretaceous lithofacies are considered. The genetic groups are marked. These groups conform to the different zones of the sea basin starting from littoral zones with an active hydrodynamics up to the abyssal zones and the areas of the depressions. The inharting of monotyped facial zones of different time levels is established. Three facial regions which are following each other in space are established

The Santonian – Campanian Rock Boundary Interval within the Zhirnovsk Uplift (Volgograd Region)

A lithologically continuous Santonian and Campanian rock section has been examined; the character of rock interrelations has been determined as the one common to the junction area of the northern part of the Don-Medveditsa and the southern termination of the Rtishchevo-Balanda swells and the Karamysh depression.

Possible Changes of the Geomagnetic Field Intention in Titonian – Berrassian and Campanian – Maastrichtian

By the results of exploration of Titonian – Berriassian sections of Mountain Crimea and Campanian – Maastrichtian sections of west of the Middle Asia, Volga region and Crimea it became possible to reconstruct the special aspects of the geomagnetic field paleointensity changes. There were received the average scale of variations, that rise at the end of geological periods. It should be noted that at the end of Jurassic the average amplitude of geomagnetic field variations was lower than at the end of Cretaceous.

Upper Cretaceous Calcareous Sponges of the Southeast of East European Platform

The features of areal distribution and stratigraphic confinement of calcareous spicular sponge forms in the southeast of East European Platform are considered. The skeletons of calcareous sponges essentially representatives of the genus Porosphaera are found in the carbonates of Turonian, Coniacian, Campanian and Maastrichtian, as well as at the base of siliceous formations of the Paleocene. The Maastrichtian calcareous sponges are characterized by the highest species diversity and a wide lateral extension.