Petrogenesis and geological significance of the Jurassic Xiaoheishan pluton in the Liaodong Peninsula, East China: in-situ zircon U-Pb dating and Hf isotopic analysis

The Xiaoheishan pluton is located in the southern Liaodong Peninsula of the eastern North China Craton, and consists of deformed diorite, granodiorite and biotite granite. LA-ICPMS zircon U-Pb dating gives the age of 174-170 Ma for diorite, 174±1 Ma for granodiorite, 177±2 Ma for biotite granite and 175±2 Ma for granitic pegmatitic dike, indicating that the Xiaoheishan pluton is a Jurassic intrusive complex. Geochemical, whole rock Sr and Nd isotopic and zircon Hf isotopic data indicate that the diorite, granodiorite and granite of the Xiaoheishan pluton were result of partial melting of ancient lower crustal materials at high pressures, interacted with mantle-derived magmas. The Xiaoheishan pluton and the Jurassic magmatism in the eastern North China Craton formed in a continental crustal thickening setting that may be related to subduction of the Paleo-Pacific oceanic plate, which induced partial melting of lower crustal materials of the North China Craton.