El paso Cenomaniense-Turoniense de Menoyo (Alava):: Variaciones de la nanoflora calcárea.

• Autores: Amalia Gorostidi, Marcos Antonio Lamolda Palacios
• Localización: Geogaceta, ISSN 0213-683X, Nº. 10, 1991, págs. 54-57
• Idioma: español
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• Resumen

  • The study of calcareous nannofossil assemblages of the Cenomanian-Turonian passage (Menoyo section, N Spain) has allowed us to characterize the Lithraphidites acutus and Quadrum gartneri zones. The first appearance datum of Quadrum gartneri Prins and Perch-Nie/sen, seems us a good index to mark out the Cenomanian-Turonian boundary. The species Watznaueria barnesae presents high percentages (40% or more) in all samples, then nannofossil assemb/ages shou/d have underwent importan taphonctll ical process, e.g. less number of species with higher percentages of W. barnesae (poor preservati0i l). On the Other hand, the nannofossi/ abundance could be related to productivity of the OAE