Petrogenesis and Tectonic Implications of the Paleoproterozoic (2.35–1.80 Ga) Magmatic Rocks in the Zhongtiao Mountains, North China Craton

The southern North China Craton (NCC) preserves extensive Paleoproterozoic magmatic records, providing critical insights into Precambrian crustal growth and Columbia supercontinent assembly. This study integrates zircon U–Pb–Hf isotopic analysis with whole-rock geochemistry to systematically constrain the petrogenesis and tectonic implications of newly identified early Paleoproterozoic magmatic lithologies in the Sushui Complex, Zhongtiao Mountains. Three discrete magmatic episodes are recognized at 2315 Ma, 2176 Ma, and 1960 Ma. The 2315 Ma highly fractionated I-type quartz syenite porphyry originates from partial melting of ancient TTG rocks with minor sedimentary input, and the 2176 Ma I-type monzogranite records mixed melting of Neoarchean TTG rocks and K-enriched mafic lower crust, while the 1960 Ma high-Mg monzodiorite exhibits subduction-related geochemical signatures generated by the interaction between lower continental crust and mantle peridotite. Regional synthesis reveals that the Zhongtiao and Xiaoqinling–Lushan areas display consistent spatiotemporal magmatic evolution, together defining a coherent Paleoproterozoic tectonic framework for the southern NCC. On the basis of the new petrogenetic data, integrated with regional stratigraphic and geochemical correlations, this framework can be subdivided into three distinct stages: an early phase of crustal reworking under extensional conditions (ca. 2.35–2.25 Ga), a middle intracontinental rifting event (ca. 2.24–2.04 Ga), and a late transitional period from compression to extension (ca. 1.96–1.80 Ga).