Abstract
Mt. Hayachine lies on the margin of the northern part of the median tectonic zone of the Kitakami. The ultra-basic rocks and the basic rocks occur in the vicinities of Mt. Hayachine.
These rocks are a great deal suffered by the metamorphism at the stage of its svnkinematic intrusion. Concerning of the succesions of the igneous activities in this district, the basic rocks are formed, and then the ultrabasic rocks intrude into the mass of the basic rocks. The granodiorite occurs lastly in the southern parts of this districts.
From the mineral compositions of the ultrabasic rocks, the anther. divides the ultrabasic rocks into four zones that are (1) zone of the serpentinite, (2) zone of the relict olivine pyroxene bearing serpentinite, (3) zone of the relict olivine bearing colourless amphibole, (4) tremolite rock, (5) zone of the relict olivine bearing tremolite chlorite rock.
Before the granodiorite intrudes, the zoning of the ultra-basic rocks may have been formed by the different conditions of the metamorphism at the stage of the synkinematic intrusion.
The facts show that the metamorphism can exist between the intrusions of the ultrabasic rocks and the granodiorite.
