2009 Volume 60 Issue 7-8 Pages 395-405
Kita-Iwo-To Volcano is a dissected Quaternary stratovolcano with no fumarolic activities, belonging to the Izu-Bonin Arc. It is stratigraphically divided into older and younger volcanoes. The volcano consists wholly of subaerial lava flows, pyroclastics and volcaniclastics. Numerous thin and nearly vertical dikes crop out along the sea cliff and count up to 167. Most of them have radial patterns from the center of the island. All lavas and dikes sampled are basaltic rocks with phenocrysts of plagioclase, olivine and clinopyroxene except one andesite dike. Chemical compositions of basaltic rocks with 47.3-51.2 wt.% SiO2 and an andesite dike with 58.6 wt.% SiO2 belong to the low-K to medium-K series.
