The Dikili-Çandarli volcanics, Western Turkey: Magmatic interactions as recorded by petrographic and geochemical features

Located in the northwestern part of the Aegean region, Dikili-Çandarli volcanic suite contains products representative for the western Anatolian Miocene volcanism. They can be divided into two main groups: the Dikili and the Çandarli groups. The Dikili group is Early-Middle Miocene in age and consists mainly of pyroclastic rocks, andesitic-dacitic lavas, lava breccia, lahar flows and associated sedimentary rocks. The lavas contain disequilibrium phenocrysts assemblages. The Çandarli group consists of Upper Miocene-Pliocene lava and sediment associations. The volcanic rocks consist mainly of rhyolitic domes and basaltic trachyandesite-basaltic andesite lavas erupted along the NW-SE- and NE-SW-trending fault systems; the faults controlled the development of the Çandarli depression. Major- and trace-element chemistry indicates that the lavas are dominantly high-K, calc-alkaline, intermediate to acidic in composition. Chemical and textural characteristics of the minerals reveal that mixing was a common process in the generation of this magma. In particular, petrography, textural evidence and crystal chemistry of the phenocrysts together with variations in rock compositions indicate that basaltic-basaltic andesitic magma intruded dacite magma and is partially hybridized with it. New petrographic and geochemical data of Dikili-Çandarli volcanics are closely similar to those of the active continental margin volcanism which are interpreted as mantle-derived magmas contaminated by crustal materials.