LA-ICP-MS zircon U-Pb ages of the late Paleozoic magmatic rocks in the tectonic window along the eastern coastal Fujian Province and their geologic significance

The coastal tectonic window of eastern Fujian is located on the eastern edge of the Cathaysia Block and contains a complex metamorphic basement, which provides key clues for exploring the tectonic evolution of the Pre-Mesozoic. This paper focuses on the magmatic rocks in the Wufenglou and Daixi tectonic windows in Zhouning, Fujian Province, and applies LA-ICP-MS zircon U-Pb dating to further explore the petrogenesis and geological significance. The dating results show that the magmatic rocks formed in the Late Carboniferous (316-335Ma) and contain inherited zircons of 843-2384Ma. Thus it can be determined that the magmatic event in the tectonic window occurred in the Late Paleozoic, and the magmatic rocks perhaps sourced from partial melting of Proterozoic sedimentary rocks(variable). Combining with the previous research and the analysis of lithofacies paleogeographic changes, it is believed that the late Paleozoic magmatic rocks along the southeast coast formed in the extensional tectonic setting after intracontinental orogenesis, and the region may has undergone a tectonic transition from extrusion orogeny to intracontinental extension in the late Paleozoic, which is closely related to the intracontinental orogenesis mechanism. The research results contribute to a deeper understanding on regional geological evolution and provide new perspectives and data support for related research.