The object of the study is the carbonate section «Pacha-Lasta» (Ilych river, Northern Urals). The work is based on the study of the composition, structure of rocks and species diversity of the foraminifera contained in them. The rocks are represented by various limestones with numerous remains of foraminifera, brachiopods, corals, echinoderms, frequent calcispheres and rare stromatolites. Based on the presence in the complex of certain foraminifera genera Biseriella, Globivalvulina, various Eostaffella (including E. ikensis tenebrosa) as well as the species Endothyranopsis sphaerica and Asteroarchaediscus baschkiricus, the Venusian age of the deposits is reliably established. Stromatolite formations, which are not characteristic of the same-age deposits of the area, were established at two intervals of the studied section. They are composed of micritized colonies of cyanobacteria, among which Ortonella and Girvanella are identified. These formations belong to the type of skeletal stromatolites, which in the Silurian and Late Devonian had a certain paleogeographic position and fixed the margin of the carbonate platform. For the Ilych River basin, a consistent decrease in relative sea level is assumed after the Early Visean transgression with a change in the conditions of the open sublittoral (Tula and Aleksinsky horizons) to the conditions of insular shallow water (Mikhailovsky and Venevsky horizons). In the latter, stromatolites can sometines occur, which are not characteristic of the Upper Visean deposits of the area.

Research subject. Lower Pennsylvanian deposits exposed by mine excavations in the watershed part of South Timan. Materials and methods. The research material included data obtained by a field description of sections and an optical microscopy analysis of rock samples (26 specimens). For micropaleontological analysis, oriented thin-sections (97 specimens) were additionally prepared. Trace fossil taxa were determined based on both field photographs and collected specimens. Four oriented rock samples were used to determine the phase composition of the clay fractions from diffraction patterns. Results. The rocks of the Askynbashian (2.7 m), Tashastian (1.4 m), and Akavasian (2.5 m) Regional Stages of the Bashkirian Stage are exposed in the Ikhnitovyi quarry, and the Upper Vereiskian deposits of the Moscovian Stage (1.9 m) are exposed in the Vyemka section. The Ikhnitovyi quarry section exhibits a distinctly cyclic pattern. The cycle bases are distinguished by the appearance of coral and algae limestones, above which thin bedded fine-grained bioclastic and peloidal limestones occur. Greenish illite and chlorite clays indicate shallow sedimentation environments. The carbonate sediments experienced two cementation stages separated by the phase of compaction. The trace fossil assemblage recognized in the Ikhnitovyi quarry characterizes Cruziana ichnofacies. The Vyemka section is of particular interest due to the find of Eofusulina and the presence of typical carbonate tempestites. Conclusions. The Bashkirian deposits were accumulated under quiet shallow-water conditions (coral and algae limestones), on low-gradient tidal flats (fine-grained grainstones), and under a low hydrodynamic activity (probably low-amplitude tides). The illite and chlorite clays identify the accumulation of aeolian material (clay paticles) in ponds.

New data on the stratigraphy of Carboniferous section in the middle reaches of the Unya River (Northern Urals) are presented. Based on the study of foraminifera and calcareous algae, the Visean and Early Serpukhovian ages has been established. The paper gives a brief description of the section with the boundaries location and the indication of the characteristics of the selected stratigraphic units, paleontological phototables of the foraminifera and algae associations of the Pesterkovian, Tulian, Aleksinskian, Mikhailovian, Venevian and Kosogorskian levels are given.

Research subject. Organogenic structures such as the Moscowian-Kasimovian skeletal mounds from the Verkhnie vorota section on the Shchuger River (Northern Urals). Materials and methods. The lithological-paleoecological analysis of biohermal limestones and the determination of their fauna in thin sections (60 samples) and polished slabs (10 samples) taken in outcrops 39 on the Shchuger River, 89 m thick. Results. It is revealed that the Middle-Upper Carboniferous skeletal mounds were characterized by a three-level food chain at three stages of their development. Cyanobacteria, calcimicrobes and green algae were the suppliers of organic matter. Their further consumers were bryozoans, brachiopods, fusulinids, small foraminifera and bacteria. Omnivores and predators were absent. It is found that, heterotrophs were the most common organisms at the stabilization stage, while autotrophs were typical of the colonization stage. The paleocenoses of the Kasimovian skeletal mound had a more extensive composition. Here, each developmental stage was represented by two types of paleocenosis, compared to the Moscowian mound. Conclusions. It is found that the main external abiotic factors that controlled the development of the biocenosis in the sites under study were the hydrodynamic regime and sea level fluctuations. An important internal factor was the development of bio-induced cement on the skeletons of organisms, which contributed to the formation of solid frameworks of buildings. Another internal factor was the widespread occurrence of Anchicodiaceae algae, which caused a decrease in the biodiversity of other groups of organisms. The data obtained allowed us to conclude that a shallow sea basin with a good aeration and low hydrodynamic regime existed in this area in the MiddleLate Carboniferous. A decrease in the basin area in the Late Carboniferous was manifested by a reduction in not only algal taxa, but also the biodiversity of the entire ecosystem.

Research subject. Carbonate rocks in the “Shirokoe Place” section (Unya River, Northern Urals). Material and methods. The work was based on a study of the composition and structural peculiarities of rocks and species diversities of forami- nifera and calcareous algae in the most important section of Upper Visean sediments in the lower reaches of the Unya river.Results. The rocks in the section are represented by bioclastic limestones, dolomites and various transition differences. The section features a wide presence of green Koninckopora, red Epistacheoides and Ungdarella algae. Less common are Palaeoberesella, Anthracoporella, Kamaena and Stacheoides. Fasciella is extremely rare, and Calcifolium is virtually absent. Foraminifera complexes are representative, but there are no zonal species Eostaffella tenebrosa (Venevsky horizon), genera Valvulinella (Tula horizon), Bradyina and Howchinia (Mikhailovsky and Venevsky horizons). Endothyranopsis, Janischewskina and Cribrospira are rare.Conclusions. The study of the species diversity of foraminifera and calcareous algae allowed us to clarify the stratigraphic division of the upper Visean sediments in the “Shirokoe Place” section. The Tula, Aleksinsky, Mikhailovsky and Venevsky horizons of the Upper Visean were reliably identified. The studied section can be used as a reference when creating stratigraphic schemes of Later Visean deposits for the Western subzone of the Upper Pechora transverse sinking of the Western folded zone of the Urals and adjacent areas of the PreUrals regional trough.

Research subject. This study is devoted to the Moleben-Iz section on the Ilych River (Northern Urals) composed of Upper Moscovian (Myachkovian horizon) and Kasimovian rocks. Material and methods . The composition of rock and fossil inclu-sions in 49 samples was investigated. Results . The upper part of the Moscovian is represented by an alteration of bioclastic grainstones and packstones with rare interlayers of dolostones and cherts. Microcodium structures were found in three lay-ers, which is indicative of three episodes of sub-aerial exposure. The Kasimovian lower boundary, which coincides with that of the Upper Carboniferous, is outlined by the appearance of diverse fusulinids of the usvaella genus, as well as by the first appearance of Eowariengella, Dagmarella, and Kanmeraia genera, since Pulchrellinae representatives dominate across this stratigraphic interval in northern-eastern sections of the European part of Russia, as well as in Canada and USA. At the base of the Kasimovian stage, the authors distinguished the Kanmeraia ozawai – Usvaella usvae biozone as being most consistent with the fauna composition. The Kasimovian is represented by the deposits of the Orlovskian and Kerzhakovian horizons. The deposits of the Orlovskian horizon are composed, in its lower part, by alternating grainstones and packstones, and, in its upper part, by boundstones and lime mudstones. Two levels of the development of biohermal rocks were established, rep-resenting two phases of organic buildup formation. The middle part of the Kasimovian (Montiparus montiparus zone) in the studied section was not established, which is likely to have resulted from a break in sedimentation. Upper Kasimovian deposits (Kerzhakovian horizon) are represented by highly silicified bryozoans packstones. These rocks serve as an excellent marking horizon, which is typical of the Northern Urals and partly of the Chernyshev Ridge. Conclusion. The Moleben-Iz section represents a range of biologic and geologic events, out of which the appearance of new Pulchrellinae genera and a marking horizon at the base of Kerzhakovian horizon are the most notable events.

1972) часто отсутствует конкретная информация.По этой причине сложно или невозможно установить возраст пород до

ÏÅÐÂÀß ÍÀÕÎÄÊÀ ÔÎÐÀÌÈÍÈÔÅÐ Â ËÓÄËÎÂÑÊÎÉ ÊÀÐÁÎÍÀÒÍÎÉ

ИЗВЕСТКОВЫЕ ВОДОРОСЛИ БАШКИРСКОГО ЯРУСА (СРЕДНИЙ КАРБОН) ЗАПАДНОГО СКЛОНА ЮЖНОГО УРАЛА (РАЗРЕЗЫ АСКЫН, БАСУ, КУРЬЕЛГА)© 2018 г

Fossiliferous carbonate rocks dredged during the "Arctic-2012" cruise on the Mendeleev Rise (eastern Arctic) provide proof of the presence of Upper Silurian(?)-Middle Devonian, Famennian-Tournaisian, Bashkirian-Kasimovian, Gshelian-lower Asselian(?) and Kungurian-Kazanian carbonate deposits. The wide spectrum of facies includes deposits of both photic zone (with fusulinids, algae, relicts of microbial and coral reefs) and deeper dysphotic areas (with trilobites, deep-water tentaculitids and ostracods). The results obtained suggest that there were at least three periods of carbonate platform sedimentation during the latest Silurian(?) to Permian. The Late Silurian?-Devonian biota do not show biogeographical differentiation, but rather are distributed globally. Shallow-water foraminifera and some algae of early Pennsylvanian-basal Cisuralian age belong to the warm-water province. These forms are unknown in the Moscovian-Permian of the Boreal Realm (Taimyr, New Siberian Islands, Verkhoyanie, Omolon Massif) but are typical for Alaska and Arctic Canada, Wrangel Island, Chukotka, Polar Urals and Svalbard. The disappearance of warm-water biota during late Artinskian-Kungurian times led to a subsequent predominance of smaller foraminifera: this assemblage with Protonodosaria is widely distributed in Permian deposits of Novaya Zemlya, Urals, Barents Sea and the eastern Arctic. The warm-water Bashkirian-Asselian biota suggests that the Mendeleev-Chukotka-Wrangel block was a low latitude shallow basin with predominant carbonate sedimentation, being part of the Arctida supercontinent, connected temporarily with the eastern margin of Laurasia (Chukcha-Alaska block).

ÂâåäåíèåÊàìåííîóãîëüíûå îòëîaeåíèÿ øèðîêî ïðåäñòàâëåíû â áàññåéíå ð.Èëû÷, ãäå îíè âñêðûâàþòñÿ íà ïðîòÿaeåíèè îêîëî 40 êì.Íà íåêîòîðûõ ó÷àñòêàõ ðåêè îáíàaeàþòñÿ íåïðåðûâíûå ðàçðåçû îò ãîðèçîíòîâ äî öåëûõ îòäåëîâ êàìåííîóãîëüíîé ñèñòåìû.Íåñìîòðÿ íà ýòîò, êàçàëîñü áû, áëàãîïðèÿòíûé ôàêò, ñòðàòèãðàôèÿ êàðáîíà áàññåéíà ð.Èëû÷ ðàçðàáîòàíà åù¸ äîâîëüíî ñëàáî, õîòÿ ýòîé ïðîáëåìå ïîñâÿùàëè ñâîè ðàáîòû

In the Urals Carboniferous 11 algae zones allowing to make interregional and intercontinental correlation of coeval deposits are established by author. For more fractional dividing of carbonate profiles on algoflora for the first time akmezones have been used. In Lower Carboniferous of the Urals are established 9, in Middle and Upper Carboniferous - 5 akmezones.

It is analyzed the evolution and biostratigraphic role of species Verella, Eofusulina, Paraeofusulina and Postverella from subfamily Eofusulininae in Upper Bashkirien and Lower Moskovien sediments of Middle Carboniferous in the Urals. Verella species characterizes the Upper bashkirien, the beginning of the Moscovien stage is fixed by major spindly fusiform Eofusulina triangula and E. triangula rasdorica, which along with zonal types of Aljutovella aljutovica and Depratina prisca reference points of the boundaries of the Bashkirien and Moscovien stages and can be recommended as a marker taxa of the Middle Carboniferous stages.