We investigated the K-Ar ages and the petrological and geochemical features of lava units from lateral cones and lava distributed around the Aso caldera in central Kyushu, Japan, in order to constrain the spatial range of lateral magma intrusion d...
Koji Uno   Yoko Kaneshige   Kuniyuki Furukawa   Taro Shinmura   Masaya Miyoshi   
Earth Planets and Space 65 331-336 2013年6月 [査読有り]
Rhyolite is a common volcanic rock; however, few studies have focused on the remanent magnetization of rhyolite lava, and few paleomagnetic studies have successfully investigated rhyolite lavas. We suspect that problems associated with paleomagnet...
Masaya Miyoshi   Hirochika Sumino   Yasuo Miyabuchi   Taro Shinmura   Yasushi Mori   Toshiaki Hasenaka   Kuniyuki Furukawa   Koji Uno   Keisuke Nagao   
Journal of Volcanology and Geothermal Research 229 64-73 2012年6月 [査読有り]
We determined the K-Ar ages for post-caldera lavas from Aso volcano in central Kyushu, Japan using the unspiked sensitivity method. The following three peaks of highly-frequent volcanism are recognized in the post-caldera stage: 70-50 ka, 40-20 ka...
Koji Uno   Tetsuji Onoue   Kazumasa Hamada   Saki Hamami   
Geophysical Journal International 189 1383-1398 2012年6月 [査読有り]
Middle Triassic (Anisian) red bedded cherts were collected from the Ajiro area in Kyushu Island, southwest Japan, for a palaeomagnetic study. Thermal demagnetization showed five distinct remanent magnetization components from the cherts. The lowes...
Koji Uno   Kuniyuki Furukawa   Shigeki Hada   
Earth and Planetary Science Letters 303 153-161 2011年2月 [査読有り]
A new paleomagnetic study illustrates latitudinal translation of ribbon-shaped continental fragments along the western margin of the Pacific Ocean. Though tectonic translations have long been recognized as prominent features in the eastern Pacific...