Petrographic and geochemical characteristics of the Tertiary Bağburun volcanites around Sarıalan (Altıeylül, Balıkesir)

The Bağburun volcanites, located in Altıeylül, Balıkesir, were examined for their petrographic and geochemical properties to enhance the understanding of Neogene volcanism in western Anatolia. These rocks predominantly comprise plagioclase, amphibole, biotite, sanidine, and altered clinopyroxene. Textural features, such as sieve-textured plagioclase and the presence of xenoliths, indicate complex crystallization processes, including magma mixing and assimilation. The major element geochemistry reveals a high-K calc-alkaline nature, characterized by decreasing MgO and TiO2 and increasing K2O content. Variations in Na2O and Sr contents are likely indicative of alteration. Trace element patterns exhibited LILE enrichment, HFSE depletion, negative Eu anomalies, and elevated La/Yb (13.5–18.2) and Th/Nb (13.5–18.2) ratios, suggesting a multicomponent magma source involving mantle melts, subplate fluids, and continental crustal contributions. Their spatial distribution implies that magma ascent was facilitated by local fault systems. In summary, the Bağburun volcanites represent a localized yet significant manifestation of Neogene magmatism in western Anatolia, contributing to a more comprehensive understanding of the tectonic evolution of the region.