SHRIMP U – P b zircon ages of the H ida metamorphic and plutonic rocks, J apan: I mplications for late P aleozoic to M esozoic tectonics around the K orean P eninsula

A new U–Pb zircon geochronological study for the H ida metamorphic and plutonic rocks from the T ateyama area in the H ida M ountains of north central J apan is presented. The U–Pb ages of metamorphic zircon grains with inherited/detrital cores in paragneisses suggest that a metamorphic event took place at around 235–250  M a; the cores yield ages around 275 Ma, 300 Ma, 330 Ma, 1 850 Ma, and 2 650 Ma. New age data, together with geochronological and geological context of the H ida B elt, indicate that a sedimentary protolith of the paragneisses is younger than 275 Ma and was crystallized at around 235–250 Ma. Detrital ages support a model that the H ida B elt was located in the eastern margin of the N orth C hina C raton, which provided zircon grains from P aleoproterozoic to P aleozoic rocks and also from A rchean and rare N eoproterozoic rocks. Triassic regional metamorphism possibly reflects collision between the N orth and S outh C hina C ratons.