LA-ICPMS zircon U-Pb dating of the Hudian gneissic monzogranite in the western segment of the North Qinling and its geological significance

Abstract：The Hudian deformed intrusion in the north of Baoji batholith consists of gneissic monzogranite. Zircons from the rock yielded a LA-ICPMS U-Pb age of 1770±13 Ma. Petrologic and geochemical study shows that the gneissic monzogranite formed in a subduction-collision environment on the plate margin and that the magma originated by partial melting of mid-upper crustal materials. The tectonic setting and age of this deformed intrusion are in the main consistent with those of the Gongjiangou deformed intrusion in the Taibai batholith, representing a strong tectono-magmatic event occurring in the western segment of the North Qinling orogenic belt in the terminal Paleoproterozoic and initial Mesoproterozoic. The event broadly corresponded to the Lüliang movement and might have certain genetic relation to the formation of the supercontinent Columbia. This new information has great significance for the study of the Proterozoic tectonic framework and tectonic evolution in the North Qinling orogenic belt and the dynamics of continental of China.