Turkey is characterised by widespread post-Oligocene volcanism. In western Anatolia, volcanic activity began during the Late Oligocene-Early Miocene in a compressional regime. A widespread suite of andesitic and dacitic calc-alkaline rocks was erupted in this period. They were accompanied by locally-developed high-level granitic intrusions. The abrupt change from N-S compression to N - S stretching in the middle Miocene was accompained by a gradual transition to alkali basaltic volcanism.