On the Satsuma Peninsula granitic rocks, Kagoshima Prefecture, Japan

Granitic intrusives ranging in composition from granodiorite through granite porphyry and quartz porphyry to rhyolite are abundant and are distributed in a separate form of a small scale in Satsuma Peninsula, Kagoshima Prefecture, Kyushu. For convenience they are called as Satsuma Peninsula granitic rocks. Optical investigation shows that their mafic minerals are strongly chloritized over through the bodies. Their chemical compositions have been determined from 22 analyses from 5 bodies. The granitic rocks are characterized by the high value of K2O/Na2O ratio. Field and laboratory investigations show that the Satsuma Peninsula granitic rocks are characterized by the features of characteristic occurrence and strong chloritization on mafic minerals and have almost the same feature in composition as granitic rocks of the Southwestern Outer Zone-type.