The specificity of paleocoenosis and a trophic structure of the Upper Ordovician Bol’shaya Kos’yu reef (Northern Urals)

The study of the spatial-temporal and paleoecological structures of the paleocenoses of the Bolshaya Kosyu reef showed that the sphinctozoic sponges Amblysiphonelloides reticulata Rigby & Potter, 1986 and Corymbospongia sp. starting from the late Ordovician could settle in sublittoral environments with active hydrodynamics in close connection with cyanobacteria, which played a leading role in the functioning of the trophic structure of this ecosystem. Fossilized biofilms and glycocalyx, tubular and worm-like bacteriomorphs found on the surface of sponges are evidence of active participation of microbial organisms in the life of sphinctozoal sponges.

Composition of algae in the Middle-Upper carboniferous skeletal mounds on the Shchuger river

Lithological-paleoecological study of the Mid–Upper Carboniferous reef limestones from the section «Verkhnie Vorota» on the Shchuger River revealed the complex of green phylloid algae Ivanovia tenuissima Khvorova, Eugonophyllum konishi Kulik, Anchicodium gracile Johnson, which are directly involved in the construction of buildup frameworks. Problematic Tubiphytes, rare cyanobacteria Bevocastria sp., dasiclads Clavaporella sp., Pseudoepimastopora cf. likana (Kochansky et Herak), Pseudoepimastopora sp., Asphaltinella cf. horowizi Mamet et Roux, phylloid Neoanchicodium sp. and red Ungdarella uralica Maslov, Komia sp., Flugelia johnsoni (Flugel) algae were associated with them. The revealed algal complex indicates the existence of a shallow warm sea with good bottom illumination and weak water movement.

The situation of studies of the Upper Paleozoic reefogenic formations on the Podcherem River (Bol'shaya Synya Depression, Pre-Urals Foredeep)

Different views on the Upper Paleozoic reefogenic limestones in the section of the Podcherem River during the period from 1960 to 2003 are presented. There are contradictory opinions of thickness, age, and section structure of the Upper Carboniferous (?) — Lower Permian reefogenic limestones of the Podcherem River. Underscore, a different interpretation of their paleogeographic position in the sedimentation basin and modern tectonic structure. To resolve controversial questions, focused research on theis reefogenic limestones is necessary.

Microbial structure in the Visean deposits of the Ilych river (Northern Urals)

The paper presents data on the distribution of microbial formations in the Visean rocks of the Ilych River basin (Northern Urals). They were found to be present in significant numbers only in the Venevian level. Stromatolites were found in the Visean on the Ilych River for the first time.

Organogenic buildings from the Wenlockian of Chernov swell

A description of coral-stromatoporatic and stromatolitic Wenlockian biostromes in the Bezymyanny Brook section in the Chernov Swell is given. Fossil associations allow to date the studied biostromes as Wenlockian.

The Miocene bryozoan biogerms of the Kazantip Cape, Crimea: the role of gas-fluid seepage in their genesis

A complex of modern physical investigations of carbonate crusts covering Lower Miocene bryozoan limestone from the Kazantip Cape showed that bryozoans built a biohermal skeleton due to the synsedimentation of bioinduced cement. The mineral association (Mg-calcite + aragonite) indicates the existence of near-bottom environment typical for gas-hydrate biogenic mineral formation as a result of bacterial methane oxidation during the formation of bioherms. The presence of bitumen, pyrite, strontianite, barite, kutnohorite and traces of vital activity of carbonate-depositing methanotrophic bacteria in the composition of carbonate crusts is concerned with a significant influence of near-bottom local gas-fluid seeps.

Formation conditions of the Lover Kasimovian (Upper Carboniferous) organic buildups on the Ilych River (Northern Urals)

Lower Kasimovian organic buildups in the Moleben-Iz section on the Ilych River, Northern Urals, were studied. Two levels of buildups development have been established, that are composing by algal and palaeoaplysinid boundstones and biocementstones. They are probably a part of long (up to 10 km) and complexly constructed biostromes. Lithological data indicate the formation of these buildups in the normal marine sutidal conditions on the carbonate ramp.

Features of composition and structure of carbonate buildups in the northern zone of the Middle Atlantic ridge

The results of mineralogical and geochemical studies of deepsea carbonate buildups dredged from areas of modern volcanism in the rift valley of the northern Atlantic Ocean were obtained for the first time. Morphology, anatomy, chemical and microelement compositions of buildups are characterized. Mineralized biofilms with bacteriomorphic structures were revealed. Using the methods of X-ray diffraction and RSMZ analysis, the main carbonate minerals of the buildups were diagnosed and studied, and the phenomenon of the anomalous nature of the isotopic composition of carbon and oxygen in them was revealed. It has been suggested that the cause of the abnormally heavy oxygen isotopic composition in carbonate buildups is the borrowing of oxygen by carbonate-forming bacteria directly from sulfates, often distinguished by isotopeheavy oxygen.

Specific minerals in bryozoan bioherms and polychaetian limestones (Kazanthip reserve, Crimea)

The object of our research is the Kazantip Cape (Kerch Peninsula, Crimea). Its attraction is a ring-shaped rock massif composed of bryozoans previously considered to be a reef structure growing on the limbs of rising brachyanticline about 8 million years ago. Application of complex of investigating methods show that clay deposits underlying bryozoan structure are composed of expandable mixed-layered minerals, smectite, kaolinite, chlorite, illite with accessory minerals (zircon, monazite, ilmenite). These clays are the result of eruption of fossilized analogue of mud volcano. This process was accompanied by unloading of cold gas-fluid seepage. Specific mineralization (barite, celestine, strontianite, authigenic minerals of rare-earth elements and manganese) of bryozoan’s bioherms indicates that the seep process continued even after the waning of mud volcanism.

Oil potential of the Asselian-Sakmarian reefogenic buildups of the Varandey-Adzva zone of the Timan-Pechora Province

Massive deposits in reef were discovered in separate fields of Varandey-Adzva zone (Naulskoye, Labaganskoye, etc.). These bodies are represented by organogenic-detrital limestones, fractured with porosity of 8-10%. They have the form of separate buildings, developed locally, wedging out along the strike within the same area. The deposits are confined to the secondary reservoirs of the pore and pore-fracture type.