Abstract: Petrochemical features of the volcanics of the area between Tokat and Sivas are described. Volcanicswhich are found in the ophiolitic melange as being blocks have the characteristics of tholeitic rocks formed . atmid-ocean ridges. Upper Cretaceous (possibily Turonian) aged volcanics seem to be identical to those formed atsubdu;ction zones. They have the characteristics of calcal caline volcanics indicating the first phase and its continuation of island arc formation. Eocene  possibly younger volcanics indicate the last product of differentiation ofcalcalcaline rocks differentiation.