Abstract: Peridotite, ophiolite, blueschist and marble are the major rock types northeast of Tavşanlı, In the areastudied a large peridotite massif tectonically overlies an ophiolite melange. This ophiolite melange consists of volcanic and sedimentary rocks (spilite, pyroclastie, chert, shale, pelagic limestone etc.), and lenses of serpentinite. Althoughrocks of the ophiolite melange appear unmetamorphosed in the field, a detailed petrographic study has revealed that allhave undergone an incipient high pressure/low temerature metamorphism. Bluschists sensu stricto are produced by theprogressive metamorphism of this ophiolite sequence. Two stages of blueschist metamorphism have been recognised inthe field and by petrography. In the first stage the typical paragenisis of lawsonite-sodic pyroxene-ehlorite is produced inthe metabasites. Sodic amphibole develops in the second stage through a reaction between sodic pyroxene and chlorite. Thesubsequently produced glaucophane lawsonite blueschists are the most extensive lithology in the studied area. They lieconformably on a thich marble sequence, which has undergone the same high pressure/low temperature metamorphism anddef ormation as the surrounding blueschists.