Ichnology of Upper Cretaceous–lower Palaeogene deep-sea deposits in the Haymana Basin of Central Anatolia

Abstract

Upper Cretaceous to lower Palaeogene carbonate and siliciclastic deposits that crop out widely in the Haymana and Polatlı districts (Ankara Province) of the Haymana Basin (Central Anatolia) are rich in larger benthic foraminifera, various macrofossils and ichnofossils. The ichnofossils of the Haymana and Yeşilyurt formations were studied at five localities. The Upper Cretaceous siliciclastics of the Haymana Formation contain moderately diverse trace fossils, belonging to the deep-sea Nereites ichnofacies. The Paleocene siliciclastic and carbonate deposits of the Yeşilyurt Formation comprise similar trace fossils, which do not show significant changes in comparison to the Haymana Formation. This indicates that the K-Pg boundary extinction event did not affect the ichnofauna with any longer consequences.

The Upper Cretaceous coarser, siliciclastic deposits of the Haymana and Beyobası formations are rich in shallow-marine, larger benthic foraminifera, including species of Orbitoides, Omphalocyclus, Siderolites, Hellenocyclina, and Loftusia, whereas fine siliciclastic deposits contain abundant planktonic, open-marine foraminifera, such as Globotruncana and Heterohelix. Palaeogene siliciclastic to carbonate deposits of the Kartal, Yeşilyurt and Çaldağ formations are rich in the larger, benthic foraminifera Nummulites, Discocyclina, Assilina and Alveolina. The larger foraminifers have been redeposited from nearby, shallow-marine parts of the basin.