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Infrazonal subdivision of the Volgian Stage in its type area by ammonites and its Panboreal correlation

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Infrazonal subdivision of the
Volgian Stage in its type area by
ammonites and its Panboreal
correlation
Rogov M.A.
Russia, Mosсow, Geological Institute of RAS
Volgian stage
Since the beginning
of study of the
latest Jurassic of
the european part
of Russia its
succession could
not be directly
correlated with
those of the
Western Europe
Ammonites virgatus Buch
Ammonites catenulatus Fischer
The Volgian Stage
has been proposed
by S.N. Nikitin (1881,
published in Russian
and German) for the
uppermost part of the
Jurassic System: “für
die ganze Masse
jurassischer
Schichten in
Mittelrussland, die
über dem Oxfordthon
liegen, ebenfalls eine
besondere
Benennung
“Wolgaformation”
einzuführen”
Threefold subdivision of the Volgian Stage has been established since
60th years of the XX century and used for the whole Arctic
Most important features of biohorizons are:
•
•
•
- potential indivisibility to those taxonomic criteria on
which they are established;
- determinacy of the both lower and upper boundary of
biohorizons in a geological section;
- identification from recognition of the single (unique)
index-taxon (usually species or subspecies)
Infrazonal scales are based on combination of phylogenetic and
immigrational bioevents
Gorodischi section
Murzicy section
Lower Volgian Substage
Lower Volgian Substage
Ilowaiskya – “Pseudovirgatites” succession
Lower Volgian Substage
Paralingulaticeras efimovi
Neochetoceras spp.
Lower Volgian Substage
Schaireria
neoburgense
Franconites cf. vimineus
Lower Volgian Substage
Presence of some Submediterranean taxa in the Volgian Stage of the
Russian Platform permits the possibility of direct correlation of the
Lower Volgian with Tithonian succession
Lower Volgian Substage
Correlation chart of the beds around the Kimmeridgian–Volgian boundary
and its equivalents through Europe (Rogov, Price, 2010)
Middle Volgian Substage
Eganovo section
Gorodischi section
Middle Volgian outcrops
Middle Volgian Substage
Zaraiskites
Middle Volgian Substage
Virgatites
Middle Volgian Substage
Epivirgatites and Laugeites
Upper Volgian Substage
Ammonites in the Eganovo
section
Milkovo section
Eganovo section, Moscow area
Upper Volgian Substage
Kachpurites lineage
Upper Volgian Substage
Garniericeras, Craspedites (Trautscholdiceras)
and Volgidiscus
Comparative completeness of the selected Middle-Upper Volgian sections
Laugeites spp.
Nordvik, N. Siberia
Craspedites praeokensis - okensis
Nordvik
European Russia
N. Siberia
European Russia
Volgidiscus
Craspedites (Taimyroceras)
Nordvik, N. Siberia
Panboreal correlation of the Volgian Stage
Thanks for your attention!
Автор
Nastya
Nastya65   документов Отправить письмо
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