Uşak-Güre havzasının Volkano-sedimanter evrimi, Batı Anadolu

The Uşak-Güre basin is a well-preserved NE?SW-trending basin located on the northern part of the Menderes Massif, in western Anatolia. The basin contains a Lower to Upper Miocene volcano-sedimentary succession that records the un-roofing of the metamorphic rocks of the Menderes Massif. The new 40Ar/39Ar radiometric data demonstrate that Cenozoic volcanism commenced (17.29 Ma) with the emplacement of the Elmadağ volcano, synchronously with deposition of the İnay group. The youngest radiometric age is obtained from the Beydağı volcano (12.15 Ma) in the south, indicating that the volcanic activity migrated from north to south with time.Low-angle detachment surfaces are clearly defined in the basin for the first time. Photomicrographs of the metamorphic rocks of the Menderes Massif as a footwall unit of the Simav Detachment Fault (SDF), show that transition of the ductile to brittle deformation.Three stratovolcanoes has been described in the Uşak-Güre basin. These stratovolcanoes display the features of subaqueous-subaerial environments, and all volcanic sequences consist of complex successions of effusive-extrusive and explosive phases. The products of the explosive volcanism and related magma-water interactions have been described for the first time in the western Anatolia.Three distinct volcanic unit are classified in the Uşak-Güre basin: (1) the Beydağı volcanic unit composed of shoshonite, latites and rhyolitic lavas followed by dacitic and andesitic pyroclastic deposits; (2) the Payamtepe volcanic unit composed of potassic intermediate composition lavas (latites and trachytes); and (3) the Karaağaç dikes composed of andesite and latite. Volcanic rocks of the basin are characterized by strong enrichment in LILE and LREE and depletions of Nb-Ta and Ti on MORB-normalized multi-element diagrams. Geochemical features of the volcanic rocks suggest that they experienced mixing processes between mafic and felsic end-members and also fractional crystallization of dominantly plagioclase and pyroxenes from mixed magma compositions.