Albitite from Izuruha, Yamaguchi Prefecture

Abstract

Albitite from Izuruha can be found in dike-like form, in the metamorphosed tuffaceous sandstone of Shimonoseki subgroup (Kanmon group), which is included in Izuruha granodiorite.
Albitite is composed chiefly of mosaic, sometimes porphyritic, albite aggreates, with a little interstitial quartz, chlorite and epidote.
By field observations and chemical data, it is considered that albitite has been formed by metamnorphic differentiation within sandstone, accompanying to the introduction of soda, alumina and silica from granodiorite.