Foraminiferal assemblages from the Jurassic Alacaatli section of Central Tu
rkey are studied. The section of the reference type for the Ankara region r
epresents a transgressive rock succession spanning the time range from the
Upper Jurassic to the Valanginian. The Jurassic carbonate-siliceous rocks o
f the section are characterized by diverse foraminiferal assemblages that i
nclude both benthic and planktonic species. The occurrence of characteristi
c benthic foraminiferal genera and species, together with the zonal plankto
nic species Globuligerina oxfordiana (Grigelis) allows these deposits to be
correlated within the Oxfordian in general and to distinguish separate sub
stages and foraminiferal zones. The peculiar feature of the considered asse
mblages is their composition represented by cosmopolitan forms without any
endemic Tethyan species. Paleoecological peculiarities of these biocoenoses
indicate that foraminiferal communities lived in deep open-marine environm
ents. This is also confirmed by the composition of radiolarian assemblages
coexisting with foraminifers.