Geochronological and Petrogenesis of the Late Paleozoic Granitoids: in Sakarya Zone (Sarıcakaya-Türkiye)

Abstract

This study aims to elucidate the origin and geodynamic setting of the Late Paleozoic granitoid (Sarıcakaya magmatic complex) of the Sakarya Zone by examining its petrographic, geochemical, geochronological, and tectonic characteristics. Based on field and petrographic observations, the intrusive suite was identified as gabbro, diorite, granodiorite, granite, and pegmatite. Major and trace element analyses reveal that these rocks exhibit high K-bearing calcium-alkaline, metaluminous, and I-type granitoid characteristics. Major and some minor element discrimination diagrams indicate that plagioclase, hornblende, and biotite play a significant role in fractional crystallization. Discrimination diagrams (Th/Nb, Ta/Yb-Th/Yb, Nb/Y-Th/Y) indicate a crustally contaminated, subduction-modified, enriched mantle source. Increasing Zr/Nb ratios support these interactions and ongoing magmatic differentiation. Tectonomagmatic discrimination diagrams indicate that the samples are within the volcanic arc granite (VAG) domain. U-Pb zircon dating yields ages between 321.3±1.2 Ma and 323.6±0.9 Ma, corresponding to the Late Carboniferous and Early Carboniferous periods. Chondrite-normalized REE models show LREE enrichment relative to HREEs and a negative europium anomaly attributed to plagioclase fractionation or crustal assimilation. The data indicate that the magmatic rocks of Sarıcakaya represent the southward subduction of the Paleotethys Ocean during the Permian-Carboniferous period.