Adakitic rocks from Hakusan Volcano, central Japan

Abstract

Hakusan volcanic rocks younger than a dormant period (ca 0.3-0.1 Ma) are adakitic, while older ones have geochemical affinity with common island arc andesites and dacites. Type of magma genesis is likely to have changed during the dormant period from that triggered by the dehydration of Pacific plate to that by the partial melting of Philippine Sea plate beneath the area.