Spatial U-Pb age distribution of plutonic rocks in the central Abukuma Plateau, northeastern Japan Arc

摘要

The Abukuma plutonic rocks are one of the major Cretaceous granitic suites in the Japan Arc. In the central to eastern Abukuma Plateau, intrusive ages of 115-97 Ma were obtained using zircon U-Pb method. According to the compilation of all existing U-Pb ages, seven intrusive stages were detected between 121 and 96 Ma. Especially, differences of the intrusive ages and geochemical variations were identified between the eastern and western leucocratic granitoids, which was likely due to the heterogeneity of their source rock compositions and/or difference in the depth of magma geneses.