R6: 深成岩・火山岩及びサブダクションファクトリー

[R6-08] 熊本県北部の花崗岩類のジルコンU-Pb年代

*堤 之恭¹ (1. 国立科学博物館)

キーワード：ジルコン、U-Pb年代、定置、花崗岩質岩、九州

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.