Foraminiferal micropaleontology, biostratigraphy and facies characteristics of Urla (İzmir, Western Turkey) Mesozoic carbonate sequences

In this study, Late Triassic - Jurassic rocks around Urla İçme Hill were investigated. These rocks are found within the Late Cretaceous-Paleocene Bornova Complex with tectonic boundaries and are overlined by the Neogene-Quaternary rocks. The Mesozoic aged rocks are composed of the Norian-Rhaetian Lower limestone subunit and the Early Jurassic (Liassic) Upper limestone subunits which can be correlated with the Nohutalan Formation at the lowest part of the sequence. The upper part differs from the Karaburun Peninsula sequence. The Lower limestone unit consists of biomicritic and biosparitic sub-tidal and supra-tidal limestones and contains dolomitic levels. The Upper limestone unit consists of micritic, biomicritic, biosparitic and biolithic limestones. This unit has precipitated in a changing environment from the sub-tidal to deep sea and from deep sea to the reef. Lower limestone subunit has a Norian-Rhaetian association containing Endoteba sp., Reophax sp., Aulotortus communis, Aulotortus ? impressus, Aulotortus sp., A. friedi, A. tenuis, A. gr. sinuosus, Auloconus permodiscoides, Gandinella falsofriedli, Triasina hantkeni foraminifers and includes large sized megalodonts. However the Upper limestone unit includes a micro fauna and flora consisting of Paleomayncina termieri, Bosniella sp., Orbitopsella primaeva, Orbitopsella praecursor, Orbitopsella sp. Duotaxis cf. metula, Trochammina ? sp., Lituoseptha cf. recoarensis, Siphovalvulina gibralterensis., Endotriada sp., Endotriadella sp., Meandrovoluta asiagoensis, Mesoendothyra sp., Pseudocyclammina sp., Everticyclammina praevirguliana, Duotaxis cf. metula, ve Siphovalvulina sp., foraminifers and Palaeodasycladus mediterraneous, Nipponopycus ramosus, Tubiphytes sp. and Thaumatoporella parvovesiculifera algaes. In addition to this, the subunit contains a large amount of coral and sponge reefs at its uppermost part. Late Noriyen-Rehaetian Triasina hantkeni taxon range zone and the Middle Liassic (Cinemurian-Pliansbachian) Orbitopsella praecursor taxon range zone provide the exact separation of Triassic and Liassic rocks.