Yenipazar area (bilecik) planktonic foraminifer biostratigraphy of the upper jurassic-cretaceous sequence

In this study, the planktonic foraminifera association of the Yenipazar Formation which comprises Late Jurassic-Cretaceous slope to basin sequences located in the east of Bilecik is examined and its geochronological and paleoenvironmental properties are interpreted. The 82 planktonic foraminifera species that belongs to 24 genus are determined in the 218 samples gathered from the Karahasanlar stratigraphic section which is measured within the Yenipazar Formation. The Yenipazar Formation age was determined as Albian-Late Maastrichtian according to definited planktonic foraminifera assemblage. Sea level changes in the basin during the Albian-Late Maastrichtian time interval is interpreted with the help of the abundance distribution of planktonic foraminifera species in the samples of Karahasanlar measured stratigraphic section. According to data available, the highest sea levels in Bilecik district were reached in Early Albian, Early Senomanian, at the start of Late Campanian and at the start of Early Maastrichtian; while the lowest levels were reached in Late Jurassic, Middle Albian, end of Senomanian-Early Campanian, Middle Campanian, at the end of Late Campanian and from the middle of Early Maastrichtian to end of Early Maastrichtian time interval. According to data obtained the study area, the climate was temperate-warm during Albian , after the Albian time to the Early Maastrihtiyen time, climate was cool and the sea level was in shallow character. At the Late Maastrihtiyen, environment continued to increase volcanic activity, therefore, ecology of life in environment is negatively affected is determined. Keywords: Bilecik, Paleoenvironmental, Planktonic Foraminifera, Numerical Analysis, Systematic, Upper Jurassic-Cretaceous, Yenipazar Formation.