New data on Callovian (Middle Jurassic) belemnites and palynomorphs from the Northern Caucasus, southwest Russia
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Date
2016-04
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Publisher
Instytut Geologii UAM
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Abstract
Palaeontological data on the Caucasus are highly important for large-scale stratigraphical and palaeobiogeographical
assessment of the northern Tethyan margin, but this information is often scarce and not available in English. Field studies
in the Northern Caucasus have now permitted to amass some new data. Two belemnite species are described from
the stratotype section of the Kamennomostskaja Formation (Callovian, Middle Jurassic) near the town of Kamennomostskij
in Adygeja (Northern Caucasus). These are Belemnopsis subhastata (von Zieten, 1831) and Rhopaloteuthis ominosa
Gustomesov, 1968. The latter is a rare species, and the present find allows new insights into its taxonomy. A palynological
analysis of the belemnite-bearing sample was carried out, and a diverse assemblage of dinocysts, acritarchs and
prasinophytes, plus pollen and spores recognised. The most abundant palynomorphs are Micrhystridium and Classopollis.
Data on belemnites coupled with those on palynomorphs indicate the early Callovian age of the sample level. This
interpretation differs slightly from previous conclusions based on ammonites and dinocysts. If this age is correct, the
degree of condensation of Callovian deposits in the section studied was lesser than previously assumed.
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Keywords
macroinvertebrates, microfossils, condensed section, Mesozoic, Adygeja
Citation
Geologos, 2016, 22, 1, pp.49-59.
ISBN
ISBN 978-83-232187-4-6