Ammonites and Infrazonal Stratigraphy of the Lower Bathonian Besnosovi Zone of the Russian Plate
— Ammonites and deposits of the lower Bathonian Besnosovi Zone of the central and southern regions of the Russian Plate are studied. The paper discusses the infrazonal stratigraphy and correlation of two reference sections: the Pletnyovka Quarry in the north of the Penza oblast and the Sokur Quarry...
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Published in | Stratigraphy and geological correlation Vol. 27; no. 1; pp. 95 - 117 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
Moscow
Pleiades Publishing
2019
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | —
Ammonites and deposits of the lower Bathonian Besnosovi Zone of the central and southern regions of the Russian Plate are studied. The paper discusses the infrazonal stratigraphy and correlation of two reference sections: the Pletnyovka Quarry in the north of the Penza oblast and the Sokur Quarry near the city of Saratov. The successive biohorizons Oraniceras issae, O. calvum, and O. besnosovi are recognized on the basis of ammonites of the genus
Oraniceras
(family Parkinsoniidae) in the Besnosovi Zone. Provisional O. mojarowskii and O. scythicum biohorizons are proposed below the above-mentioned biohorizons, whereas the O. cf./aff. besnosovi Biohorizon is proposed above them. The Besnosovi Zone corresponds to the middle part of the Western European Zigzag Zone. The Michalskii Zone underlining the Besnosovi Zone apparently corresponds to the Bajocian–Bathonian boundary interval. It is suggested that only one A. excentricum migrational biohorizon, corresponding to the upper part of the O. besnosovi Biohorizon and correlating with the lowermost part of the Ishmae Zone of the Boreal scale, can be established on the basis of Boreal ammonites of the genus
Arcticoceras
in the Sokur Section. Central Russian representatives of the genera
Oraniceras
[M] and
Sokurella
[m] are assigned here to the subfamily Pseudocosmoceratinae that is eudemic to the Central Russian late Bajocian–early Bathonian sea. It is suggested that the above-mentioned genera evolved from
Pseudocosmoceras
[M and m] that is cryptogenic neoendemic of the East European Peritethyan marine basin. New species are described:
Oraniceras issae
sp. nov. [M],
O. calvum
sp. nov. [M],
Sokurella pletniovkae
sp. nov. [m], and
S. elshankae
sp. nov. [m]. |
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ISSN: | 0869-5938 1555-6263 |
DOI: | 10.1134/S0869593819010039 |