Petrography and petrology of The Yürekli (Bal？kesir) volcanics: an example of post-collisional felsic volcanism in the Biga peninsula (NW Turkey)

In this study, the aim was to determine the petrography, geochemistry and source of the Yürekli volcanics (Biga Peninsula, NW Turkey). Tertiary volcanism is widespread in Western Anatolia (NW Turkey), which is an important area where tectonic and magmatic events are observed together. Yürekli volcanic rocks comprise dacitic lavas and pyroclastics. Dacitic lavas show porphyric and hyaloporphyric texture, and consist of plagioclase, quartz, amphibole, biotite, sanidine and Fe-Ti oxide minerals with apatite and zircon accessory minerals. Petrologically, they have high-potassic and calc-alkaline characteristics. Yürekli volcanics show enrichment in large ion lithophile elements (LILE) and are depleted in high field strength elements (HFSE) on the N-MORB normalized diagram. On the chondrite-normalized rare earth element (REE) plot, light rare earth elements are enriched but heavy rare earth elements are depleted in the rocks. REE patterns are concave shaped (mean LaN/LuN=16–25) and show slight negative Eu anomalies (0.66–0.81). Plagioclase, amphibole and biotite fractional crystallisation and crustal assimilation are important in the evolution of the Yürekli volcanics. According to all data, it can be argued that the Yürekli volcanics formed in a post-collisional setting, and the parental magmas were derived from the melts of enriched lithospheric mantle