Petrological investigation of Ulukale (Çemişgezek) porphyritic stock and Çağlarca (Hozat) radial dykes in Tunceli volcanics

Within the scope of this thesis, mineralogical-petrographic and geochemical features of Çemişgezek-Ulukale dome (It has a height of 300 m and a perimeter of approximately 1500 m) and Hozat-Çağlarca radial dykes (seven different lengths) found in the Late Miocene aged Tunceli Volcanites were investigated and the results were compared with the surrounding volcanics. Despite their morphological and formation differences, both rock groups showing similar petrographic features have porphyritic texture and andesitic composition. The difference is that the pyroxene mineral is found in the dykes and some of the mineral contents that make up the dykes are more basic in composition compared to the dome minerals. As a result of geochemical investigations, it was determined that both groups of rocks, which were determined to be in trachyandesite composition, had calcalkaline-shoshonitic and peraluminous properties and also all elemental changes or behaviors were similar to each other. Nd-Sr isotope data show a mantle - lithospheric source characteristic in the enriched source region of both rock groups. All geochemical data reveal that these volcanics have low-grade partially melted spinel-peridotitic source magma, however, magma mixture with assimilation-fractional crystallization, the effect of continental crust in the form of contamination and the effect of sediment melts developed due to subduction are important in the formation of magma differentiation. In addition, all these data show that these volcanics have the same petrological characteristics as the Tunceli Volcanites, which are the main magmatism product. Keywords: Tunceli Volcanics, Çemişgezek-Ulukale, Hozat-Çağlarca, dome, dyke, Nd-Sr isotope, petrology