The calcareous nannofossils and magnetostratigraphic results from the Upper Tithonian-Berriasian of Feodosiya region (Eastern Crimea)

This article is concerned with nannofossil study of Tithonian-Berriasian sediments of Eastern Crimea. The NJT 16, NJT 17a, NJT 17b, NKT, and NK 1 nannofossil zones were determined. The occurrence of Nannoconus kamptneri minor, one of the potential marker-types of the Tithonian-Berriasian boundary (the base of the NKT Zone) of the Tethyan sequence in the Feodosiyan section is assigned here to the Pseudosubplanites grandis ammonite Subzone and the magnetic Chron M18n. The base of the NKT Zone is closer to the Grandis Subzone base than to the base of the Jacobi Subzone. Contradictions in the interpretation of magnetic chrons obtained by the present authors (Arkadiev et al. 2018) and by Bakhmutov et al. (2018) might be caused by mistakes admitted in the latter work on the compiled section.Fil: Arkadiev, V.. Saint Petersburg State University; RusiaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Concheyro, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Guzhikov, A.. Saratov State University; RusiaFil: Baraboshkin, E.. Moscow State University; Rusi

Magnetostratigraphy of the Upper Berriasian “Zavodskaya Balka” section (East Crimea, Feodosiya

The results of magnetostratigraphic investigations in the Upper Berriasian Zavodskaya Balka section (Feodosiya, Crimea) are presented: magnetic polarity information, data on magnetic susceptibility, its anisotropy (АМS), frequency dependence (FD-factor) and other petromagnetic parameters. The analysis of the thermomagnetic and magnetic saturation curves has proved the presence of magnetite, being the main carrier of the remanent magnetization. Magnetic cleaning with alternating field and with temperature mostly has revealed the two-component composition of the magnetization, and the magnetostratigraphy is based on the directions of the most stable of them, with unblocking field from 35–50 mT and temperature from 300 to 540°C. The palaeomagnetic column presented specifies four heteropolar magnetozones – analogous to the M16 and M15 magnetic chrons (full M16n and M15r, parts of M16r and M15n). The existence of the M16n.1r subchron (“Feodosiya”) is substantiated, and it should be included into the Geomagnetic Polarity Time Scale. By bio- and magnetostratigraphic correlation, the section studied is an age analogue of the Paramimounum, Picteti and Alpillensis (probably Otopeta) subzones of the Boissieri Zone. The calculated sedimentation rate varied from 26.6 to 29.5 m/My

Some peculiarities concerning the Pliocene evolution of the Black Sea and Caspian basins

Volume: 21Start Page: 477End Page: 48

Some features of the Early Cretaceous sedimentation in the Cis-Caucasia reflected in magnetic properties of the sedimentary cover

Volume: 21Start Page: 365End Page: 38

Calcareous nannoplankton and the upper Tithonian – Berriasian magnetostratigraphy in Theodosiaarea, the east Crimea

This is the description of nannoplankton assemblages for the first time reported from the upper Tithonian - Berriasian sequences in Theodosia area of East Crimea. Relationships between nannoplankton assemblages and magnetic zones are examined. Close characteristics of the lowermost parts of the Grandis ammonite subzone, NKT nannoplankton zone and M18r magnetic zone serve as the basis for the authors to offer the base of Grandis subzone to be the Tithonian - Berriasian boundary.Fil: Arkadiev, V.. Saint Petersburg State University; RusiaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Concheyro, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Guzhikov, A.. Saratov State University; RusiaFil: Baraboshkin, E.. Moscow State University; Rusia10th All-Russia MeetingMagadanRusiaInterdepartmental Stratigraphic CommitteeRussian Foundation for Basic ResearchMinistry of Science and Higher Education of Russi

Microbiostratigraphy of the Berriasian–Valanginian boundary in eastern Crimea: foraminifers, ostracods, organic-walled dinoflagellate cysts

Thorough study of foraminifers, ostracods and dinoflagellate remnants from the Zavodskaya Balka and Koklyuk sections helps to characterize the detailed biostratigraphic division of the Berriasian / Valanginian boundary sequence in the Feodosiya district of eastern Crimea. The foraminifer and dinocyst associations from the lower part of the sequence are clearly comparable with common Berriasian associations throughout all Mountain Crimea. On the other hand, foraminifer, ostracod and dinocyst associations from its upper part have been recorded only in eastern Crimea. The upper foraminifer level corresponds to the boreal ammonite zones from the Tauricum-Verrucosum (Upper Berriasian-Valanginian). Most of the ostracod species are endemic. The base of the uppermost dinocyst level correlates with the Lower Valanginian Paratollia zone from north-western Europe

Integrated stratigraphy of the reference sections for the Callovian-Oxfordian boundary in European Russia

The most complete succession of the Callovian-Oxfordian boundary recorded in European Russia is the Dubki section, where the authors have carried out integrated paleontological and magnetostratigraphical studies. A continuous sequence of the West-European biostratigraphic units in the interval from the Lamberti to the Cordatum Zones is present in this section, and 10 ammonite biohorizons have been recognized. Additional data concerning nannofossil assemblages, foraminifers, ostracods, belemnoids and the paleomagnetic polarity for the Dubki section are also presented. The Callovian-Oxfordian boundary, marked by FAD of the genus Cardioceras, is placed at the base of the scarburgense biohorizon. The paleontological richness and continuity of the succession make the Dubki section a possible GSSP candidate for the Callovian/Oxfordian boundary. Correlation of the Dubki ammonite succession with those of the other GSSP candidates, Redcliff Point and Thuoux, is proposed. Other sections studied in Russia have yielded some additional observations on the Callovian-Oxfordian boundary beds. Although in the Dubki section the praemartini biohorizon is not found, its existence is proved, however, in Orenburg region (Khanskaya Gora). In the Datchovskaya section (Northern Caucasus) the paucicostatum biohorizon is characterized by an unusual combination of Subtethyan and Boreal ammonites, including Kosmoceras, which is not typical of the paucicostatum biohorizon outside the Northern Caucasus

Integrated stratigraphy of the Upper Barremian–Aptian sediments from the south-eastern Crimea

Previous studies made in different parts of the world have shown that Barremian–Aptian times imply many difficulties in deciphering the biostratigraphy, microfossil evolution and correlation of bioevents. In an attempt to improve our knowledge of this period in a particular area of the Tethyan realm, we present the first integrated study of microbiota (including planktonic foraminifera, calcareous nannofossils, ostracods and palynomorphs) and magnetostratigraphy of the upper Barremian–Aptian sediments from south-eastern Crimea. The nannofossils display the classical Tethyan chain of bioevents in this interval, while the planktonic foraminifera demonstrate an incomplete succession of stratigraphically important taxa. Our study enabled the recognition of a series of biostratigraphic units by means of four groups of microfossils correlated to polarity chrons. The detailed analysis of the microfossil distribution led to a biostratigraphic characterization of the Barremian/Aptian transition and brought to light an interval, which may correspond to the OAE1a

Ammonites and magnetostratigraphy of the Berriasian–Valanginian boundary deposits from eastern Crimea

Euthymi, Crassicostatum and Callisto ammonite subzones, correlable with Paramimounum, Picteti, and Alpillensis subzones and probably with the Late Berriasian Otopeta Subzone of the Boissieri Standard Zone have been recognized in calcareous clays of the Berriasian-Valanginian boundary sequence in the Feodosiya district (eastern Crimea). The ammonite Leptoceras studeri (Ooster) suggests Late Berriasian to Early Valanginian age. Geomagnetic polarity indicates M16-M14r magnetozones. Therefore, the base of the Valanginian sequence in eastern Crimea should be placed within the M14r magnetozone