| mhorn | Дата: Saturday, 17.09.2011, 11:58 | Сообщение # 1 |
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| Shurygin B.N., Nikitenko B.L., Meledina S.V., Dzyuba O.S., Knyazev V.G. (2011) Comprehensive zonal subdivisions of Siberian Jurassic and their significance for Circum-Arctic correlations // Russian Geology and Geophysics. Vol.52. P.825–844.
pdf: http://rghost.ru/21921381
Authors show the present state of the set of parallel zonal scales for the Siberian Jurassic, based on various fossil groups, and the principles of their construction. We discuss the significance of Siberian biostratigraphic scales for the Boreal zonal standard of the Jurassic units. The stratotype region for this standard must have a typical Boreal (Arctic rather than mixed) fauna. A possible candidate is Siberia (and the Arctic biochorema), which is located in the center of the Panboreal Superrealm, where the set of interrelated scales for various fossil groups is the most complete. The set of parallel zonal scales for the Siberian Jurassic is efficient for the subdivision and correlation of Jurassic units in various Arctic regions (Barents Sea shelf, northeastern Russia, Arctic Alaska, Arctic Canada).
[added by mhorn] unfortunately, some details of used ammonite zonal subdivision are contradicts with other data or based upon poor data. For example, Arctocephalites arcticus Zone corresponding to lowermost Bathonian on the base of presence of Oxycerites close to O. aspidoides, but the type horizon of the O. aspidoides is Upper Bajocian (cf. Dietl, 1982), and O. aspidoides faunal horizon is now recognized within Parkinsoni Zone, Bomfordi Subzone (Dietze & Dietl, 2006). Base of the Kimmeridgian in the authors’ opinion is marked by FAD of the Amoebites, while it should be drawn one zone below.
Middle Jurassic - Lower Cretaceous ammonites & aptychi
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