Japan Geoscience Union Meeting 2015

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International Session (Oral)

Symbol S (Solid Earth Sciences) » S-MP Mineralogy & Petrology

[S-MP09] Supercontinents and Crustal Evolution

Wed. May 27, 2015 11:00 AM - 12:57 PM 201A (2F)

Convener:*Madhusoodhan Satish-Kumar(Department of Geology, Faculty of Science, Niigata University), Yasuhito Osanai(Division of Evolution of Earth Environments, Faculty of Social and Cultural Studies, Kyushu University), Geoffrey H. Grantham(Council for Geoscience, P/Bag X112, Pretoria, SOUTH AFRICA), Sajeev Krishnan(Centre for Earth Sciences, Indian Institute of Science, Bangalore 560 012, INDIA), Tomokazu Hokada(National Institute of Polar Research), Chair:Tetsuo Kawakami(Graduate School of Science, Kyoto University), Tomokazu Hokada(National Institute of Polar Research)

12:54 PM - 12:57 PM

[SMP09-P10] Spatial U-Pb age distributions of plutonic rocks in the central Abukuma Plateau, northeastern Japan Arc

*Yoshiaki KON1, Terumi EJIMA1, Tetsuichi TAKAGI1 (1.GSJ, AIST)

Keywords:Abukuma, granite, zircon, U-Pb, LA-ICP-MS

Intrusive ages of the Abukuma plutonic rocks, a major Cretaceous granitic suite in the Japan Arc, were determined using zircon U?Pb age method. The U?Pb ages of the ‘Hbl-Bt granitoids’ distributed in the western to central part of the Abukuma Plateau were 113-99 Ma, whereas five ‘east leucocratic granitoids’ intruded within a short time range of 112-106 Ma. The U?Pb ages of a gabbro from the Mt. Katasone and of the ‘western leucocratic granitoid’ were115.2 ± 1.1 Ma and 96.7 ± 1.0 Ma, respectively. The above age distribution combined with geochemical results suggests that. Based on these zircon U?Pb age, significant difference of the intrusive age between ‘east-’ and ‘west leucocratic granitoids’ was indicated.