ABSTRACT

Several specimens of coexisting biotite and hornblende were separated from the rapakivi granites, Svecofennian and Karelian granitic rocks of Finland and subjected to D/H ratio measurements and chemical analyses. D/H distribution between biotite and hornblende in the rapakivi and Svecofennian granitic rocks showed the disequilibrium situation defined by KURODA et al. (1977a). The origin of equilibrium and disequilibrium granites was discussed on the basis of the content and state of water in magmas.