f Foraminiferal response to sedimentary cyclicity in the Haymana Basin (Central Anatolia, Turkey)

The aim of this research was the determination of the foraminiferal response to sedimentary cyclicity. The results of the field works on exposures of the Cretaceous-Paleocene deposits located in the Haymana basin demonstrated the high-frequency cyclicity in sedimentation, accompanied by rapid lateral and vertical depositional environment change. The sedimentary sequence is mainly characterized by flyschoidal sequence that is composed of alternation of siliciclastic and carbonate units in the Cretaceous-Paleocene age. It is possible to observe several full depositional sequences developed from low stand system tracts to transgressive and high stand system tracts. The depositional setting during accumulation of this succession has changed from pelagic to neritic environments. On the background of these cycles, the depositional series of higher order containing sediments formed during very small scale sea level fall and rise. <br>We also carried out the microfaunal analysis, which displays significant presence of foraminifers and an insignificant presence of ostracoda shells represented by genera Leptocythere, Caspiella, Xestoleberis and etc. The foraminiferal assemblages of this sequence were determined in detail and quantitative analysis of them was carried out. By detail investigation of microfauna and determination of foraminifer species under the microscope, we also pinpointed the C/T boundary in the section, which is indicating the mass extinctions of Cretaceous foraminifers represented by genera Planoglobulina, Globotruncana, Globorotalia, Heterohelix and appearance of new genera such as Globoconusa, Igorina, Globanomalina in the Tertiary time. Diversity and abundance of the assemblages was analyzed in order to demonstrate the response of the foraminifers to sedimentary cyclicity.<br>