Peritectic assemblage entrainment and mafic-felsic magma interaction in the Late Oligocene-Early Miocene Karadag Pluton in the Biga Peninsula, northwest Turkey: petrogenesis and geodynamic implications

Abstract

The Hellenic subduction system governs the entire Aegean region through the creation of a migrating magmatic arc that has existed since the beginning of the Early Cenozoic. The Karadag Pluton is situated in the NW part of Turkey and represents one of the distinct snapshots of this subduction system during the Late Oligocene-Early Miocene Period.iod. It consists of 2 major lithological units, based on their petrographic and geochemical features, comprising: 1) main plutonic facies (SiO2 70 wt.%) that are represented by cordierite-free and cordierite-bearing leucogranites. Zircon U-Pb laser ablation inductively-coupled plasma mass spectrometry and K-Ar dating revealed crystallization and cooling ages of 23.9 +/- 0.5 Ma and 20.2 +/- 0.9 Ma for the main plutonic bodies, and 22.0 +/- 1.1 Ma for the leucogranite facies, respectively. The pluton had a high-K calc-alkaline affinity and exhibited a metaluminous to peraluminous (aluminum saturation index of