Metablastic hornblende gabbro and diorite from the middle of Horoman river, Hidaka, Hokkaido

Hornblende gabbro, diorite and gabbro-diorite occur in the sheared zone of biotite gneiss and basic hornblende plagioclase rocks. Careful observations on the occurrence of these rocks and the comparison of the component minerals between the coarse igneous textured rocks and the country metamorphic rocks have revealed that the basification and the acidification of plagioclase occur more intensively in igneous textured rocks than in metamorphic rocks, and moreover quality of the country metamorphic rocks provide for that of gabbro and diorite and the regulation is not vice versa. Consequentry, these igneous textured rocks in these districts are the metablastic rock originated from the country rocks, from which it is produced by metamorphic differentiation.