Abstract:This study systemically presents the geochemical features and zircon U-Pb and Lu-Hf isotopic compositions of Yinmabin plutons and mafic dykes in the central Mogok metamorphism belt, Myanmar, with an emphasis on their petrogenesis and sources and geological implications. The Yinmabin granodiorites are geochemically characterized by medium SiO2 (64.3%~65.5%) and high Na, with N2O/K2O =1.5~1.75 and A/CNK=0.94~0.97, enrichment in LREE (Sr and Ba >500×10-6) and high field strength elements (HFSE) such as Nb, Ta, Zr and Hf, nd depleted in HFSE. These geochemical features of the Yinmabin granodiorites are of attribute of active continental margin calc-alkaline I-type granite. The LA-ICP-MS analysis yielded an age of 131~135 Ma for the zircon from Yinmabin granodiorite and 120~118 Ma for diabases. The Yinmabin granodiorite are heterogeneous in zircon εHf(t) values (-15.66~-2.99) with a mean of -8.77, yielding younger zircon Hf crustal modal ages of 795~1569 Ma. While zircons from diabases dykes show εHf(t) values from -13.72 to +5.82 (averaging -2.72) and a corresponding mean tDM age of 570~1341 Ma. This suggests that the rocks mainly derived from partial melting of ancient crust with the addition of depleted mantle material. The similar Lu-Hf isotopic compositions to that of the Tengchong and North Lasha magmatism belt indicate that early Cretaceous magmatic belt in the Mogok-Maodanmian block formed in the similar geological background as the Bomi-Chayu-Gaoligong-Lasha magmatic belt. This suggests it be part of southward extension of the Tengchong magmatic rock belt. Combined with petrogenesis, source characteristics and the previous research results, it can be concluded that the formation of Early Cretaceous Yinmabin granodiorite and mafic dyke were closely related to the subduction of the Luxi-Mogok oceanic plate and that the ocean-continent transformation occurred at about 120Ma. The research has important geological significance in understanding the process of subduction and collision of the mid-Tethys ocean during the Late Mesozoic in the Mogok metamorphism belt.