Sedimentology and Stratigraphy of Tertiary Evaporitic Sediments in the South of Ulukisla (Nigde)

Abstract

This study includes the research of a tertiary aged and mostly evaporitic sedimentary basin, which is located in the district Ulukışla (Niğde), and northern part of Mount Bolkar of the Middle Taurus (Toros) Mountains. This region is an inner marinal basin that was formed after the Paleocene in the north of a collision zone of an old ocean in the southern branch of the Neo-Tethys, which is closed between Upper Cretaceous and Lower Paleocene. In the south of the region, the Upper Cretaceous units were thrust with reverse faults on Paleocene units towards south. Within the borders of our field, there are deformations that were indirectly caused by these overthrusts. In our study, we have researched and explained the sedimentological features of sediments which are between Paleocene-Pliocene aged sediments around Ulukışla (Nigde) and the sedimentation mechanism of evaporates with environmental conditions during this forming and geological evolution of the region. The oldest unit in the study field is the Şimşim formation (Alihoca ophiolite), which is Upper Cretaceous aged, ophiolithic and of dark grey-green colour. The Sansartepe Formation that is Paleocene aged and represented by pillow lavas stays discordantly over this formation (because deformation in the pillow lavas is less than the deformation in Şimşim Formation and according to stratigraphic rules it must be an unconformity between them). Then, Serenkaya Formation, which is Lower-Middle Eocene aged and generally represented by the sediments with coarse, angular, sub-angular fragments and blocks concordantly, overlies Sansartepe Formation. Most of the material of the Serenkaya Formation is from the Sansartepe Formation. After Serenkaya Formation, the Güney Formation, which is Middle-Upper Eocene aged, comes concordantly.