Radiocarbon dating of pyroclastic flow deposits on southern slope of Kuju Volcanic Group and their significance

Okuno, Mitsuru*; Nagaoka, Shinji*; Kokubu, Yoko   ; Nakamura, Toshio*; Kobayashi, Tetsuo*

Kuju Volcanic Group, located in middle Kyushu, Japan, consists of lava domes and small stratovolcanoes. We present here results of AMS C dating of pyroclastic flow deposits (Pfl) on southern slope of the Kuju Volcanic Group. The C dating has conducted by AMS (JAEA-AMS-TONO) under the Common-Use Facility Program of JAEA. The Handa Pfl was the biggest eruption during the last 200 kyrs and the AMS C age was about 54 kBP. Shirani Pfl and Muro Pfl are block-and ash flow type and the C ages were 48 kBP and 41 kBP, 32 - 34 kBP, respectively. These ages can be correlated with Thermoluminescence ages for lava domes of Kutsukake-yama and Hossho-zan. This study demonstrates that the lava dome and block-and ash flow deposits formed at the summit area after the eruption of Handa Pfl.