scholarly journals Palaeomagnetic Inclination Error in the Red-beds Deposits: A Contribution from the Ediacaran Sedimentary Rocks of the Western Part of the East European Platform

Author(s):  
Marek Lewandowski ◽  
Tomasz Werner ◽  
Grzegorz Karasiński ◽  
Darko Matesič ◽  
Mariusz Paszkowski
2021 ◽  
Author(s):  
Alvina Chistyakova ◽  
Roman Veselovskiy

<p>There's no doubt that nowadays detrital zircon U-Pb geochronology is actually required method of sedimentary basins analysis. Furthermore, this approach may have a lot of applications, such as a stratigraphic correlation. Here we present the first results of U–Pb LA–ICP–MS dating of detrital zircon from the Permian-Triassic red beds located within the Moscow Basin of the East European platform. Two outcrops have been studied: the Zhukov Ravine P/T boundary reference section and the Nedubrovo strata with uncertain stratigraphic position (uppermost Permian or lower Triassic?).</p><p>U–Pb ages of detrital zircon grains have been obtained for two samples – the Upper Permian and Lower Triassic age, which were taken in the proximity to the Permian–Triassic boundary in the Zhukov Ravine. Corresponding age distributions show contrasting provenance of the studied sedimentary rocks, pointing out that principal change in source of clastic material occurred on the Paleozoic-Mesozoic boundary. It means that detrital zircon U–Pb geochronology can be used as an additional independent tool for stratigraphic correlation of the Permian-Triassic red beds, at least within the Moscow Basin. We demonstrate this in the case of the Nedubrovo section with debated (Permian or Triassic?) stratigraphic position: the obtained data on detrital zircons persuasively suggests Early Triassic age of the Nedubrovo strata.</p><p>This study is supported by the Russian Foundation for Basic Research (project no. 18-05-00593).</p>


2020 ◽  
Author(s):  
Anna Fetisova ◽  
Roman Veselovskiy ◽  
Valeriy Golubev ◽  
Alvina Chistyakova ◽  
Mikhail Arefiev ◽  
...  

<p>We present the combining results of 6-year comprehensive studies, which have been done on fifteen key sections the Permian-Triassic red beds located within the Russian Basin (East European platform). In our presentation we discuss some aspects of paleomagnetism and rock magnetism of sediments, such as inclination shallowing, anisotropy of magnetic susceptibility and so on. The main achievement of our work is getting the new mean Permian-Triassic paleomagnetic pole for the East European platform as well as calculation of its Late Permian and Early Triassic poles. We also present new version of the magnetostratigraphic correlation of studied sections within the Russian Basin and with Global Geomagnetic Polarity Time Scale, taking into account obtained results of U-Pb LA-ICPMS dating of detrital zircons and paleontological constraints. One of the most intriguing conclusions of our work is a suggestion about the existing of quite long-lasting time interval of non-GAD (Geocentric Axial Dipole) configuration of the Earth's magnetic field close to the Permian-Triassic boundary, evidences of which we have found in some of studied P-Tr sections. This study is supported by the grant of the RFBR (18-05-00593).</p>


2020 ◽  
Vol 492 (1) ◽  
pp. 306-310
Author(s):  
A. V. Chistyakova ◽  
R. V. Veselovskiy ◽  
D. V. Semenova ◽  
V. P. Kovach ◽  
E. V. Adamskaya ◽  
...  

2009 ◽  
Vol 83 (2) ◽  
pp. 161-196 ◽  
Author(s):  
Nataliya G. Vorob'eva ◽  
Vladimir N. Sergeev ◽  
Andrew H. Knoll

The Kel'tminskaya-1 borehole, drilled along the northeastern margin of the East European Platform (EEP), reveals some 3,600 m of Neoproterozoic sedimentary rocks, mostly confined to the subsurface. The upper 1,000 m of the drilled section correlates with late Ediacaran Redkino and Kotlin successions on the EEP, whereas the lowermost 2,000 m can be related to pre-Sturtian (Upper Riphean) deposits in the Ural Mountains. In between lies the Vychegda Formation, a 600 m siliciclastic succession that has no counterpart in classic EEP stratigraphy.Vychegda microfossils can be separated into three assemblages. The upper part of the formation contains large, profusely ornamented acritarchs broadly comparable to those of the Ediacaran Complex Acanthomorph Palynoflora, including species of the generaAlicesphaeridium, Asterocapsoides, CavaspinaandTanariumconfined to Ediacaran-aged assemblages elsewhere. Diverse large acanthomorphs are known from Ediacaran strata around the world, but have not previously been recognized from the EEP, an absence attributed to a hiatus between the glacial Laplandian (>635 Ma) and Redkino (mostly <555 Ma) successions. The large acanthomorphic acritarchs record eukaryotic organisms with resting stages in their life cycles and likely include egg or diapause cysts of early animals. In contrast, the lower Vychegda assemblage, found in the basal 10 m of the succession, contains taxa typical of earlier Neoproterozoic successions. The middle assemblage contains only simple filaments and spheroidal acritarchs.The most parsimonious interpretation of Vychegda biostratigraphy is that pre-Marinoan rocks in the basal part of the formation are separated by a cryptic unconformity from early and middle Ediacaran deposits above. This interpretation is consistent with data from China and Australia, which indicate that the major paleontological transition to diverse ECAP assemblages took place within the Ediacaran Period and not in association with the preceding ice age. Vychegda acritarch assemblages thus contribute to a biostratigraphic model for the initial Ediacaran boundary.


Palaeobotany ◽  
2012 ◽  
Vol 3 ◽  
pp. 5-11
Author(s):  
A. V. Gomankov ◽  
V. F. Tarasevich

Dispersed bisaccate pollen grains of Scutasporites nanuki were studied by means of LM, SEM and TEM. Sacci ultrastructure of these pollen grains was rather peculiar. Sacci were like a thin fi lmy fringe attached to the central body near the equator. They were fi lled with sporopollenin elements of irregular shape and various dimensions with equally various cavities between them. Such an ultrastructure is called as spongy. The morphology and ultrastructure of S. nanuki is discussed in the context of the evolution of early conifers.


2005 ◽  
Vol 7 (5) ◽  
pp. 1-12
Author(s):  
M. A. Nagornyi ◽  
V. G. Nikolaev

2020 ◽  
Vol 157 (12) ◽  
pp. 2081-2088
Author(s):  
Sergey B Felitsyn ◽  
Eugeny S. Bogomolov

AbstractAn enhanced concentration of phosphorus has been found at the stratigraphic level of the disappearance of Ediacaran taxa in two areas, the Cis-Dniester region and the Moscow syneclise, on the East European Platform (EEP). The isotope composition of neodymium was determined in Fe sulphide and phosphorite in the same beds. Measured εNd(t) values in diagenetic phosphate nodules are similar to those in iron sulphide from the same layer. During the Ediacaran − Early Cambrian, accumulation of radiogenic Nd in the epeiric basins on the EEP increased progressively from −17.9 and −19.4 in pyrite from the sequence bottom to −7.9 and −8.5 in the Early Cambrian pyrite of the central part of the EEP. The Ediacaran phosphate nodules show εNd(t) ranging from −12.9 to −15.0, while that in the Early Cambrian nodules is typically c. −9.0. These data indicate the secular change in Nd isotope composition of the water reservoir on the EEP from Ediacaran to Cambrian.


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