The Mount Kozak magmatic complex, western Anatolia

The Mount Kozak igneous complex is located close to the towns of Ayvalik, B ergama and Burhaniye in the Western Anatolia, Turkey. Magmatic activity occ urred during the Late Oligocene-Early Miocene, beginning with the emplaceme nt of the Kozak pluton. Sheet intrusive rocks formed around it coevally. Th ey are surrounded by the volcanic rocks, partly contemporaneously with the emplacement of the granitic rocks during the Early Miocene. The Upper Oligo cene-Lower Miocene magmatic rocks of the Kozak region are represented by a high-K, calc-alkaline suite of predominantly intermediate and acidic compos ition. Their geochemical characteristics suggest that the magmas are hybrid , and were formed from a similar source, representing mantle-derived magmas , contaminated by crustal materials. The cogenetic plutonic rocks, the hypa byssal rocks and the overlying volcanic associations are related to one ano ther in space and time, and appear to have been connected to a shallow leve l granitic intrusion in a caldera collapse setting. The calc-alkaline magma tic activity waned during the Middle Miocene. When the volcanism was rejuve nated during the Late Miocene-Pliocene, alkaline basalt lavas were formed a s fissure eruptions. (C) 1998 Elsevier Science B.V. All rights reserved.