Zircon fission-track ages of some pyroclastic flow deposits in the Kagoshima City area, Japan

Abstract

Seven new fission-track ages of zircons from pyroclastic flow deposits in the Kagoshima City area, southern Kyushu, have been determine by the external detector method. The ages of the deposits are as follows: Omine 1, 2.2±0.4 (±2σ) m. y.; Omine 3, 0.7±0.2 m. y.; Omine 4, 0.5±0.2 m. y.; Omine 5, 0.5±0.2 m. y.; Kogashira 2, 0.7±0.1 m. y.; Yoshino, 0.5± 0.2 m. y. and Mifune, 0.9±0.2 m. y. These data were supplemented with previously determined fission-track ages for the Upper Kakuto, 0.3±0.1 m. y., Lower Kakuto, 0.3±0.1 m. y. and Giono, 2.0±0.4 m. y. to provide time markers for future correlations. All the ages, except the Mifune rhyolite, are consistent with the stratigraphy in the Kagoshima City crea.