The Dikili-Çandarlı Volcanics, Western Turkey: Magmatic Interactions as Recorded by Petrographic and Geochemical Features

Located in the northwestern part of the Aegean region, Dikili-Çandarlı volcanic suite contains products representative for the western Anatolian Miocene volcanism. They can be divided into two main groups: the Dikili and the Çandarlı 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 Çandarlı 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 Çandarlı 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-Çandarlı volcanics are closely similar to those of the active continental margin volcanism which are interpreted as mantle-derived magmas contaminated by crustal materials