Cuisian orthophragminid assemblages (Discocyclina, Orbitoclypeus and Nemkovella) from the Haymana-Polatli Basin (central Turkey): Biometry and description of two new taxa

Ozcan E.

ECLOGAE GEOLOGICAE HELVETIAE, vol.95, no.1, pp.75-96, 2002 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 95 Issue: 1
  • Publication Date: 2002
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.75-96
  • Keywords: Orthophragminids, Discocyclina, Orbitoclypeus, Nemkovella, biometry, cuisian, central Turkey, CENTRAL ANATOLIA, PALEOCENE
  • Akdeniz University Affiliated: No


The Paleocene - early Lutetian sedimentary succession of the Haymana-Polatli basin (central Anatolia, Turkey) comprises extremely fossiliferous shallow-water units. Some sections of this succession were formerly proposed to serve as reference sections for early Thanetian - early Lutetian Shallow Benthic Zones (SBZ), which developed within the framework of the integrated zonation of the Tethyan Paleogene. The Cuisian - early Lutetian Cayraz Formation, the uppermost unit of the Haymana- Polatli basin, is a thick, shallow-marine elastic - carbonate unit known by its diverse assemblages of nummulitid, alveolinid and orthophragminid foraminifera. The lower part of this unit, considered to be Cuisian in age, was studied for its orthophragminids at its type locality. Orthophragminids identified for the first time in this Anatolian material from the lower part of the Cayraz Formation comprise diverse assemblages of Discocyclina, Orbitoclypeus, Nemkovella and partly Asterocyclina, which characterise the early-middle and late Cuisian Shallow Benthic Zones (SBZ 10-11/12). Identified taxa belong to the same evolutionary lineages that are present in the northern Mediterranean, from the Pyrenees through Aquitaine, northern Italy and Slovakia, as far as the Crimean Peninsula. Two new subspecies of Discocyclina and Orbitoclypeus, Discocyclina fortisi (d'Archiac, 1850) cairazensis n. ssp. and Orbitoclypeus douvillei (Schlumberger, 1903) yesilyurtensis n. ssp., are introduced from the upper part of the Cuisian section. A sequence of populations of Discocyclina, Orbitoclypeus and Nemkovella has been subjected to biometric analysis of the embryo and equatorial chamberlets. A comparison of these biometric results with previous data from other Tethyan Cuisian localities (mainly in Europe and the Crimea) is also made.