Petrogenesis and tectonic implications of Early Miocene adakitic granites in the Menderes Massif (western Türkiye)

The Menderes Massif, a significant Alpide metamorphic complex in Türkiye, is recognized as one of the most extensively studied core complexes globally, characterized by syn-extensional intrusions with diverse geochemical characteristics. Among these is the Güneşli granite, located in the northern Gördes submassif, which intrudes the basement migmatites. This study presents the petrography, geochemistry, Sr-Nd isotope compositions, and U-Pb zircon dating of the Güneşli granite. The intrusion consists of monzogranite, granodiorite and a late-stage pegmatite. Granodiorite is located in the core zone, while monzogranite contacts migmatites. Textures and contact relationships suggest shallow emplacement. U-Pb zircon dating yields an Early Miocene age of 22.3 ± 1.2 Ma. Geochemically, the Güneşli granite has high SiO₂ (>71.6 wt%) and is slightly peraluminous (ASI = 1.0–1.1), classifying it as I-type granite. It shows calc-alkaline to high-K calc-alkaline affinities. Source characteristics indicate high-K mafic rocks to tonalite. The high Sr/Y (avg 47.5 ppm) and La_N/Yb_N (avg 32.4 ppm) ratios, and Eu/Eu* (0.8 to 1.4), suggest an adakitic signature. Its potassic nature (K₂O/Na₂O > 0.5) and low MgO content suggest derivation from lower crustal depths rather than slab melting. Additionally, high Dy_N/Yb_N and La_N/Yb_N ratios indicate garnet presence in the source. The ⁸⁷Sr/⁸⁶Sr and εNd values range from 0.709275 to 0.712199 and from −10.6 to −7.3, suggesting the possibility of upper crustal assimilation during crystallization. The Güneşli granite was likely derived from deep crustal sections of the Menderes Massif during the Aegean extensional period, coinciding with Early Miocene core complex exhumations.