ABSTRACT

A granitic rock with an aegirine-bearing ferrosalite is found to occur as a small dyke at Myogase, Japan. In parts of the dyke the clinopyroxene granite grades into a biotite-bearing leucogranite with granophyric texture and feldspars of high temperature optics. The pyroxene granite encloses xenoliths of marbles and gneisses. Five analyses are given of rocks, together with an analysis of the clinopyroxene. No removal of aluminium from the magma is suggested and epidote, grossular andradite and the clinopyroxene itself are indicated to have locked aluminium in themselves. The very seldom occurrence of alkali pyroxene granite due to carbonate rock contamination is concluded to come from a limited availability of high temperature, dry magmas.