Geotectonic Setting and Origin of the Youngest Kula Volcanics (Western Anatolia), with a New Emplacement Model

The Quaternary Kula volcanics are Na-dominant in character while all the older volcanic rocks of western Anatolia are generally definitive K-dominant rocks. As a unique example in western Anatolia, the existence of a huge amount of plateau basalts at Kula indicates rapid uplift of mantle material, as confirmed by new geochemical data. Based on our field observations, the oldest Kula volcanics are the plateau basalts with more than one main lava flow. At the beginning of volcanic activity (first-period plateau basalts), this plateau was vast. Subsequently, parts of the first-period plateau basalts were uplifted and partly eroded while other parts were covered by younger lavas, tephra and sediments. The horsts, covered by plateau basalts, are well protected because of their resistance to erosion. During extensional activity, the development of cinder cones continued without hiatus. During the last period of volcanic activity, the youngest craters once again produced lava flows to form the second-period plateau basalts. As a result, there are more than 80 cinder cones with quite different erosional stages between the first and second plateau-basalt periods. The Kula basalts are the only example of rapid uplifting of asthenospheric material in western Anatolia, and are interpreted to form due to the opening of a horizontal slab window as a consequence of the more rapid southwestward movement of the Aegean microplate overriding Africa, with respect to the Anatolian plate.