R6: Plutonic rocks, volcanic rocks and subduction factory

[R6-08] Zircon U-Pb dating of granitoids in northern Kumamoto, southwest Japan

*Yukiyasu Tsutsumi¹ (1. National Museum of Nature and Science)

Keywords:zircon, U-Pb age, emplacement, granitoid, Kyushu

Zircons U-Pb ages were obtained from granitoids in northern Kumamoto Prefecture. Two samples from the Kikuchi Granite indicate 106.6 ± 0.9 Ma and 105.7 ± 1.2 Ma. Two samples from Tamana Granodiorite indicate 105.7 ± 0.7 Ma and 105.5 ± 0.9 Ma. The sample from Tsutsugatake Granite indicates 106.0 ± 1.0 Ma. Errors are with 95% confidential interval. Ages of all samples concentrate around 106 Ma whereas age data obtained by various dating methods showed various age of 89 to 121 Ma.