Facies and paleoecological aspects of terrestrial deposits from the ürgüp formation (Nevşehir)

The collision of Eurasian and Afro-Arabian plates during Miocene volcanic activities widespreadly occured in Central Anatolia. This province is known as Central Anatolian Volcanic Province that one of the biggest Volcanic Province in Turkey. The objective of this thesis is to research on geology, mineralogy, geochemistry and depositional environment of Neogene fluviolacustrine sediments (Ürgüp Formation) which are located between Ürgüp (Nevşehir) region in Central Anatolia. The samples were examined their mineralogical and geochemical properties by polarized-light microscopy, X-ray diffraction, scanning electron microscopy, and X-ray fluorescence analysis, stable isotope analysis (δ13C, δ18O). The Ürgüp Formation is made up of many ignimbrites, andesitic basalts and fluviolacustrine deposits. The presence of ignimbrites, andesitic lavas, tuffs, mudstone, calcrete, dolomite, dolomitic limestone, limestone and lithofacies properties indicates fluvial and shallow-lake environments in this volcanic province. Facies and facies assemblages were determined according to sedimentologic characteristics (sedimantary structures, clast size, geometry, contact and fossil content). Facies distinguished is divided into three categories; lake, volcanic-volcaniclastic and fluvial. Feldspar, quartz, calcite, opal-CT, amphibole accompanied with smectite, and illite were predominant in these palaeoenvironment. The oxygen and carbon stable isotopes and values of geochemical analysis of carbonate samples indicate that their formations occurred in drought climatic conditions. This aspect may be linked by a Messinian (late Miocene) Salinity Crisis. Moreover, data from the analyses indicate climatic and vegetational changes during late Miocene-Pliocene transition.