Comparison of The Geochemical Characteristics of Late Cretaceous Alkalen Volcanic Rocks From The Southern Border of Sakarya Zone

Alkaline volcanics exposed at similar stratigraphic levels in Upper Cretaceous at Bayburt, Amasya-Gümü？hac？k？y and Ankara-Kalecik locations along the southern boundary of the Sakarya Zone provide macroscopically two different lithologies which are containing large pyroxene porphyries and large analcimized leucite porphyries. These rocks formed as a result of the low-grade partial melting of the metasomatized phlogopite-rich mantle rocks, which resulted in the step subduction angle of the aged oceanic crust before the collision. In the course of following their cases, in the middle / shallow depths of the crust, in the magma chambers they underwent differentiation and reached two different lithologies