WAIRAKITE-ANALCIME SOLID SOLUTIONS FROM LOW-GRADE METAMORPHIC ROCKS OF THE TANZAWA MOUNTAINS, CENTRAL JAPAN

Abstract

Minerals of intermediate chemical composition between analcime and wairakite are described. They were found in the highest metamorphosed part of the laumontite and mix-layer chlorite zone of the metamorphosed area in the Tanzawa Mountains, central Japan. Chemical analyses and X-ray diffraction studies were carried out on these materials. The results plotted in the Wa-Nat-Ab′ diagram indicate that the compositional variation is more extensive than reported in the past. Possible distribution of vacant fields in the diagram is also discussed.