Vol 27, No 3 (2019)

ARTICLES
Age and formation features of the Ordovician Chalovskaya sequence in the Argun Massif, eastern part of the Central Asian fold belt
Smirnova Y.N., Sorokin A.A.

Abstract

In this paper we present the results of the mineralogical and geochemical studies of metaterrigenous rocks of the Grebnev and Magdagachi formations of the Chalovskaya Sequence – one of the key stratigraphic divisions of the Argun continental Massif in the eastern part of the Central Asian fold belt, and U–Pb geochronological (LA-ICP-MS) data for the detrital zircons from these rocks. It is established that the youngest zircons in the metasandstones of the Grebnev Formation have an age of ~478 Ma, and in the metaalevrolites of the Magdagachi Formation ~448 Ma. Together with the previously obtained data on the age of metadacites from the Isagachi Formation (476 ± 8 Ma), this information indicates the Ordovician age of the Chalovskaya Sequence, previously attributed to the Late Precambrian. It was shown that the accumulation of sediments of the Chalovskaya Sequence took place in an environment of an active continental margin or island arc simultaneously with intense magmatic activity. Taking into account the fact that the Early Paleozoic suprasubduction magmatism manifested within all the continental massifs of the eastern part of the Central Asian fold belt (Argun, Mamyn, Bureya, Jiamusi, Khanka), it cannot be excluded that the mentioned continental massifs have a common geodynamic history.

Стратиграфия. 2019;27(3):3-23
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Development of the integrated approach for stratigraphic dissolution and correlation of Middle–Upper Jurassic disturbances of south-east of western Siberia
Rychkova I.V., Shaminova M.I., Anosov V.V., Ivanov V.P.

Abstract

Based on complex paleobotanical, lithogeochemical, IR spectrometry and thermochemical studies, stratigraphic dismemberment and correlation of productive Middle–Upper Jurassic sediments, represented by Tyumen and Naunak formations in the Dvojnaya and Snezhnaya areas, in the southeast of Western Siberia (the central part of the Tomsk Region) were carried out. A reliable basis has been created for an optimal correction of the calculation of reserves and effective development of hydrocarbon deposits. It is established that for the Tyumen formation the leading paleobotanical remains are the ferns of Coniopteris vialovae, Raphaelia diamensis and Czekanowski czekanowskia irkutensis, Cz. rigida, Phoenicopsis mogutchevae, and for the Naunak formation – Czekanowski czekanowskia tomskiensis. This is due to the paleoclimatic situation, which predetermined the composition of the plant community and the types of plant-coal-forming plants. For reliable correlation, a lithogeochemical study of sediments was carried out, taking into account the analysis of the origin of the coal. The difference in the composition of plant complexes in the suites was confirmed by the difference in the genetic properties of the marking coal-bearing deposits: the degree of biochemical stability of the organic mass of the peat, the level of gelification and the floral regeneration of the organic mass of the coals, and also the yields of light and heavy hydrocarbons.

Стратиграфия. 2019;27(3):24-39
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On the non-marine stratigraphy and floras of north-eastern Russia
Shczepetov S.V., Herman A.B.

Abstract

Some decisions of the Third Inter-departmental Regional Stratigraphic Meeting on Precambrian, Paleozoic and Mesozoic of North-eastern Russia (St. Petersburg, 2002) are analysed in the light of latest data obtained. It is shown that regional stratigraphic units (‘Horizons’) of non-marine Cretaceous recognised in this Meeting are in fact not the basic subdivisions, but rather specialised biostratigraphic units, namely ‘Beds with flora’. Ages of some of these units are specified, notably Beds with Arman Flora is Turonian–Coniacian, Beds with Amka Flora is Coniacian and Beds with Arkagala Flora is Santonian–Campanian. We recommend to keep the previous names for the Penzhina, Barykov and Koryak phases of floral development and for the corresponding stratigraphic units. An updated version of the non-marine Cretaceous stratigraphic chart of the Okhotsk-Chukotka structural-facial Region is proposed to discuss.

Стратиграфия. 2019;27(3):40-52
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New data on the late cretaceous flora of the New Siberia island, New Siberian Islands
Herman A.B., Kostyleva V.V., Nikolskii P.A., Basilyan A.E., Kotel’nikov A.E.

Abstract

New plant fossils collected in 2016 from the Derevyannye Gory Formation on the New Siberia Island are studied. Thirty species of fossil plants are identified and illustrated. They belong to liverworts, ferns, ginkgoaleans, conifers and angiosperms. Sixteen of them have not beed found in the New Siberia Flora before. A new angiosperm species Dalembia (?) gracilis Herman is described. The New Siberia Flora is characterised by a moderately high taxonomic diversity, predominance of conifers and angiosperms with large-leafed platanoids and trochodendroids being the most abundant among angiosperms, by predominance of dentate-margined angiosperms and rarity of plants with entire-margined leaves, and by absence of cycadaleans and bennettitaleans. The flora existed during the Turonian–Coniacian time interval and most probably should be dated as Turonian. Plants of the New Siberia Flora experienced a warm-temperate humid climate with warm summers, mild frost-free winters and insignificant seasonality in precipitation.

Стратиграфия. 2019;27(3):53-69
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Lectostratotype of maikopian group – Belaya River section upstream of Maikop town (Western Ciscaucasia) in the Oligocene part
Popov S.V., Tabachnikova I.P., Bannikov A.F., Sychevskaya E.K., Pinchuk T.N., Akhmet’ev M.A., Zaporozhets N.I., van der Boon А., Krijgsman W., Stolyarov А.S., Krhovsky J.

Abstract

Belaya River Section of Maikop deposits is the closest to the Maikop town, typical for Western and Central Ciscaucasus, well outcropped and studied and should be considered as a type section for the Maikop Group. Here it is possible to observe a continuous transition from the underlying light marls of Belaya Glina Formation to the dark clays of Pshekha Formation at the base of the Maikop succession. Pshekha Fm is characterized by nannoplankton NP21 and NP22 zones, dinocysts Phthanoperidinium amoenum (D13) and Wetzeliella symmetrica zones, mollusk association with Pterolucina batalpashinica at the bottom and rich fish fauna. The succession shows a normal polarity chron C13n for the base of the Pshekha and revers polarity C12r above.

Marl of Polbian Bed with brackish Lower Solenovian mollusks, ostracod association with Disopontocipris oligocaenica, nannoplankton of NP23 Zone and dinocysts of Wetzeliella gohtii Zone lies above with erosion contact. Overlying Lower Morozkina Balka Subformation contains from non-calcareous clays and concludes the remains of fish and dinocysts of Wetzeliella gohtii Zone. The Upper Morozkina Balka Subformation contains calcareous sublayers with nannoplankton NP23 Zone in lower part and NP24 one above, dinocysts Chiropteridium partispinatum Zone, Rhombodinium draco Subzone. Polarity pattern we interpret to correspond to C10n, C9r and C9n.

Batalpashinsk Formation corresponds to the time of maximum hydrogen sulfide contamination of the Late Oligocene basin and is dated by nannoplankton NP25 Zone, and dinocysts Chiropteridium patrispinatum Zone with Rhombodinium draco Subzone in lower part and Deflandrea spinulosa (non typica) Subzone in the middle and upper parts. Septarian+Zelenchuk Fm is composed of clays with septarian concretions, and interbedded sands with the same dinocysts and foraminifera with Spiroplectammina aff. terekensis. Calcareous interlayers in the top of the formation conclude nannoplankton of NP25-NN1 Zone. Karadzhalga Formation is composed mainly “fish lithofacies” and includes dinocysts zone Labyrinthodinium truncatum (Lower Miocene) in basal part.

Стратиграфия. 2019;27(3):70-92
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Palynological characteristics of the Eocene–Early Miocene of Kvachina Bay, Western Kamchatka
Aleksandrova G.N.

Abstract

As a result of studying the stratigraphic distribution of palynomorphs in the Cenozoic marine strata of the Kvachina Bay section, six different age associations of dinocysts, spores, and pollen have been identified. Their analysis made it possible to date the deposits of the Tigil Unit by the Bartonian–Pribonian, the Belesovataya Unit – by the Oligocene–Early Miocene, and the overlying lower part of the Kavranian Series – by the Early Miocene. The age of the dislocated rocks underlying the Tigil Unit is estimated as Late Ypresian–(?) Early Lutetian. On the basis of the revealed changes in the ratios of the ecological groups of palynomorphs, conclusions were made about the paleoenvironmental in which the formation of strata took place in various time intervals.

Стратиграфия. 2019;27(3):93-122
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All-Russian scientific–practical conference “Paleontology in modern museum and education”
Naugolnykh S.V.

Abstract

The paper deals with the program and participants of the All-Russian Scientific-Practical Conference “Paleontology in modern museum and education”, which was organized by Geological Institute of RAS (Moscow), K.A. Timirjazev State Biological Museum (Moscow), and Krasnoufimsk Regional Museum (the City of Krasnoufimsk, Sverdlovsk region) in the City of Krasnoufimsk, August 20–24, 2018.

Стратиграфия. 2019;27(3):123-125
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