Zircon U–Pb–Hf Isotopes and Whole-rock Geochemistry of Rhyolite and Tuff from the Harachiyama Formation, North Kitakami Mountains, NE Japan

The Harachiyama Formation comprises Lower Cretaceous volcanic rocks, which are distributed in the eastern margin of Kitakami Mountains northeastern Japan. Whole-rock chemical analysis, U–Pb zircon dating and Hf isotope analysis were performed to constrain formation age magmatic origin was discussed. lava tuff samples from Omoto Tsukue areas supported island-arc rhyolitic rocks (SiO2 content > 70%), yielded weighted mean ages 127.8 ± 3.4 Ma 129.2 2.6 (2σ), respectively. Eighteen grains two samples, dated between 141.6 123.9 Ma, positive εHf(t) values +5.0 +8.7. consistent with those Granitoid reported previous studies. Therefore, it is suggested that Early Japan, such as Formation, have same Granitoid.