Short Article
Fission-track age of the volcanic rock of Tokara-Hirase, Kagoshima Prefecture.
2007 Volume 58 Issue 1-2 Pages 45-47
Details
2007 Volume 58 Issue 1-2 Pages 45-47
A FT age of 4.2±0.2 Ma is obtained from andesite lava of Tokara-Hirase, Tokara Islands. Tokara-Hirase is a summit of a conical seamount about 400 m high from the surrounding seafloor and 13 km in basal diameter. Above the sea level, small rocks distribute in an area 2.5×1.2 km. TokaraHirase consists of lavas of pyroxene andesite and quartz-phyric dacite and pyroclastic rocks, and these volcanic rocks are suffered from hydrothermal alteration in various degrees. The obtained FT age is older than the reported age of the other Quaternary volcanic islands of Tokara.
