Mineralogy of "cordierite cluster"in the Takakumayama granite, Kagoshima, Japan

Abstract

"Cordierite clusters" up to about 3 cm in diameter abundantly found in Sarugajo type granitic rock (aplitic adamellite) from Takakumayama, Kagoshima, Japan, were examined using optical microscopy, X-ray diffraction, electron probe microanalysis, and X-ray analytical microscopy. The "cordierite clusters" were composed mainly of quartz, alkali feldspar, plagioclase, garnet, cordierite, biotite, muscovite and clinochlore. Compositional map of the "cordierite cluster" disclosed that the microcrystalline clinochlore colored the cluster. An abundance of Fe in the cordierite implies that it was formed pegmatitic stage during cooling of the Takakumayama granite.