| mhorn | Дата: Tuesday, 22.09.2015, 14:49 | Сообщение # 1 |
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| Rogov M.A., Alifirov A.S., Igolnikov A.E. (2015) Revised ammonite succession of the Upper Volgian of Nordvik section: zonal boundaries and uncertainties // The International Scientific Conference on the Jurassic/Cretaceous boundary. September 7-13, 2015, Samara (Russia). Togliatti: Kassandra. P.70-76.
Revision of all ammonite records from the Upper Volgian Substage of the Nordvik section leads to the improvement of its zonal subdivision. For the first time presence of the Originalis Zone is proven for this section. However, due to rarity of ammonite occurrences in the upper part of the succession the position of the boundary between Okensis and Taimyrensis Zones remains unclear, and position of the Tithonian-Berriasian boundary (i.e. base of the Jacobi Zone) could be corresponding either to the uppermost part of the Originalis Subzone of the Okensis Zone or to the lower part of the Taimyrensis Zone
Middle Jurassic - Lower Cretaceous ammonites & aptychi
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