Ny. Bragin et Uk. Tekin, Stratigraphy and the upper Jurassic lower Cretaceous radiolarians from thecarbonate-siliceous deposits, Ankara Region, Turkey, STRATI GEOL, 7(2), 1999, pp. 130-140
In the Ankara region, the Jurassic-Cretaceous Alacaatli key section spans t
he stratigraphic interval from the Oxfordian to the Valanginian (but not al
l the three Jurassic Series, as it was believed earlier). Abundant and dive
rse radiolarian assemblages are used for the detailed subdivision of these
deposits and their correlation with the sections in the West Mediterranean
region. Three units were distinguished and dated by radiolarians: (1) the m
iddle Oxfordian-lower Tithonian (cherts and limestones, including the "ammo
nitico rosso" facies of the latter), 35-40 m; (2) the upper Kimmeridgian-Lo
wer Berriasian (limestones and marls), 33 m; (3) the upper Tithonian-upper
Valanginian (micritic limestones and calcarenites), 59 m.