ABSTRACT: îııvesttgated area Is located between Tokat and Sivas, northeast of Çırçır, It has been aimed to examine the petrochemical features of Yıldızdağı Gabbro In this paper, Yılcîızctafı Gabbro, possibly Eocene in age, Is represented by hypabyssal rocks displaying porphyritic, ophMo and poîkllitle textures. It consists mainly of labradorite-bytownlte, hornblende, rarely diopdde and olivine, m addition to opaque mineral», sphene and/or rutile. According to the result of amMyses and evaluation», İt has been defended that Yüdızdağı Gabbro ims tholeiitic character and probably formed in an arc system during Eocene.