Upper Cretaceous planktonic foraminiferal biostratigraphy from NW Turkey: calibration of the stratigraphic ranges of larger benthonic foraminifera
✍ Scribed by Sevinç Özkan-Altiner; Ercan Özcan
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 754 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0072-1050
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✦ Synopsis
Planktonic and larger benthonic foraminifers of the Upper Cretaceous (Santonian±Maastrichtian)-Lower Tertiary (Danian) rock units from north, northwest and central Anatolian fore-arc basins have been investigated in order to improve the biostratigraphic resolution of this time interval. Total abundance and diversity of planktonic foraminifers vary from rare (the sequence from the Haymana region) to high (the sequences from the Cide, C Ë aycuma, HanoÈ nuÈ and Yenikonak regions) and preservation is poor to moderate due to lithologic variation. First and last appearances of the planktonic foraminifera evaluated as major bio-events have been used to establish the biostratigraphic framework. Planktonic foraminiferal zonation from bottom to top of the succession consists of zones de®ned by Dicarinella concavata, Dicarinella asymetrica, Globotruncanita elevata, Globotruncana ventricosa, Radotruncana calcarata, Globotruncanella havanensis, Globotruncana aegyptiaca, Gansserina gansseri, Abathomphalus mayaroensis and Morozovella pseudobulloides. Ten Orbitoides and Lepidorbitoides species have been identi®ed. The dierent phylogenetic development stages of Orbitoides and Lepidorbitoides populations and other larger benthonic foraminifers, Pseudosiderolites vidali, Siderolites calcitrapoides, Siderolites denticulatus, Omphalocyclus macroporus, Cideina soÈzerii, Hellenocyclina beotica, and Clypeorbis mamillata have been calibrated with the planktonic foraminiferal zonation established in the same successions. Hence, an integrated zonational scheme composed of planktonic foraminifers and larger benthonic foraminifers has allowed a detailed stratigraphy of these successions to be erected.