Abstract: The Kemalpaşa Plio-Quaternary basin was constructed during the period of N-S extension which has beenreactivated nearly 5 Ma BP causing the opening of E-W trending grabens following a short-time compressionphase in Western Anatolia. The Kemalpaşa basin, southwestern one of the westerly furcated branches ofGediz Graben, has a Neogene basement composed of Lower-Middle Miocene and Upper Miocene-lowermostPliocene continental sedimentary sequences seperated by a regional unconformity. The Lower-MiddleMiocene Kemalpaşa group is represented by the Dereköy, Örnekköy and Topçutepe formations depositedin fandelta, lacustrine and fluvial environments respectively and the calcalkaline andesitic Yukarıkızılcavolcanics. The Çiçekliköy group, which is deposited during the Late Miocene to early Early Pliocene, consists of alluvial Ulucak formation in its lower part and overlying lacustrine Yaka limestone.The deposition in the Kemalpaşa basin, which is formed in two successive phases during the late EarlyPliocene and Holocene respectively, is represented by the Gediz group. The first phase depositsof lateEarly Pliocene-Plesitocene on the hanging wall of Gediz Graben detachment fault arethe lacustrineÇiniliköy formation and lateral alluvial Kızılca and Armutlu formations. Alluvial fan and fluvial depositsof the second phase have been deposited in the Holosen basin opening on the first phase deposits by theKemalpaşa high-angled oblique-slip normal fault.