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

Authors: ZEKİYE KARACIK, YÜCEL YILMAZ, JULIAN A. PEARCE

Abstract: 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.

Keywords: volcanism, geochemistry, mineral chemistry, mixing, Turkish Aegean region

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