Investigation of Intrusive Rocks in the Çambaşı Plateau and Bektaşyayla Region Located South of Ordu Using 40Ar/39Ar Petrology and Geothermochronology Methods

This research focuses on elucidating the tectonic processes in the Eastern Pontides by investigating the Çambaşı Quartz Syenite and Bektaş Yaylası Quartz Monzonite, situated south of Ordu province in northeastern Turkey. To achieve this, mineralogical and petrographic characteristics of the acidic granitoids were analyzed alongside 40Ar/39Ar biotite age dating and comprehensive whole-rock and mineral geochemical analyses. Samples collected from Bektaş Yaylası Quartz Monzodiorite and Çambaşı Quartz Syenite underwent crushing, grinding, sieving, and washing to prepare for age determination. The biotite minerals were embedded in epoxy, polished, and examined. After processing the rock sample, geochemical analyses, including trace and rare earth element studies, were carried out at Actlabs laboratory in Canada. The ⁴⁰Ar/³⁹Ar biotite dating yielded ages ranging from 44.50 ± 0.35 million years to 81.12 ± 0.25 million years, indicating that these intrusions formed during the Late Cretaceous and Late Paleocene periods. Geochemical data classify the acidic intrusive rocks as calc-alkaline, high-potassium calc-alkaline, and shoshonitic. Integrating geochronological and geochemical evidence, the study suggests that the Çambaşı Quartz Syenite and Bektaş Yaylası Quartz Monzonite originated from the partial melting of the mafic lower crust, driven by continental collision. These results highlight the crucial role of continental collision in the geodynamic evolution of the Eastern Pontides.. This study on the geochronology and geochemistry of the Çambaşı Quartz Syenite and Bektaş Yaylası Quartz Monzonite offers valuable insights into the tectonic processes of the Eastern Pontides. The results demonstrate that the region’s geodynamic evolution is characterized by a complex and multi-phase history.