An investigation of Microplankton assemblages from latest Albian (Vraconian) sediments
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R.J. Davey [1] ; J.P. Verdier [1]
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[1] Esso REO, Bègles, France
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- Localización: Revista española de micropaleontología, ISSN 0556-655X, Vol. 5, Nº. 2, 1973, págs. 173-212
- Idioma: inglés
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Resumen
Microplankton (dinoflagellate cyst) assemblages are described from the upper part of the Late Albian (including Vraconian) and from the basal Cenomanian. The samples examined come from two well dated sections in France and from the Vraconian type section (Switzerland). Ninety-five species and varieties are recorded; one new genus and seven new species are proposed. The distribution of these species is fully discussed, with the aid of range charts, particularly with respect to the ammonite zonation at this level and to the Albian-Cenomanian boundary. Each of the ammonite zones is characterized by certain extinctions and appearances of microplankton species; the largest floral change occurs at the base of the Stoliczkaia blanchett zone (Lower Vraconian) where twenty-five species make their first appearance in the studied sections. Finally, our results are compared with those from earlier mid-Cretaceous studies.
