Petrogenesis and tectonic implications of the Mesozoic granitoid intrusions in the eastern Liaoning Peninsula, NE China

Mesozoic magmatic rocks are widely distributed in the eastern region of the North China Craton (NCC), providing important information for understanding the Mesozoic tectonic regimes in this area. This paper reports newly obtained geological, geochemical, and zircon U-Pb-Lu-Hf isotope data for the Xiaoheishan-Daheishan intrusion (XDI) and the Yanghezhen-Dayingzhen intrusion (YDI) newly identified from Precambrian metamorphic basement range in the eastern Liaoning Peninsula, and provides a case study demonstrating that the petrogenesis of granitoid rocks was closely related to the tectonic regimes. The Middle-Late Jurassic XDI granitoids commonly have the adakite-like geochemical characteristics and their primary magma was derived from the partial melting of mafic rocks and Neoarchean tonalites in the thickened lower crust. The Early Cretaceous YDI granitoid rocks generally show diversified geochemical characteristics and their primary magma was generated by the partial melting of Paleoproterozoic metagreywackes and Neoarchean tonalites in the lower crust with minor addition of mantle-derived magma. These differences indicate that the granitoid magmatism in the eastern Liaoning Peninsula has occurred a significant variation during the Jurassic to Cretaceous. The variation of late Mesozoic granitoid magmatism may be responses to the regional tectonic transition from compression to extension in the eastern Liaoning Peninsula, which is induced by the geodynamic regime of the Paleo-Pacific Plate from low-angle subduction to slab rollback.