Host: Japan Association of Mineralogical Sciences
The Tonaru metagabbro mass occurs as a large lenticular body in the Sambagawa metamorphic belt in central Shikoku, and it consists of two different lithologies. One is diopside amphibolites, and the other is garnet epidote amphibolite, accompanied by small amounts of eclogites. Garnet epidote amphibolites composed mainly of garnet, epidote, amphibole (tschermakite, pargasite, magnesio-hornblende), plagioclase (An14-20) and quartz. Two types of garnets have been identified, coarse grained garnet up to 7 mm and fine grained garnet up to 2 mm across. The chemical compositions of the coarse grained garnet are similar to the core of the fine grain garnet.