Abstract
Fine textures and fine structures of clinopyroxenes altered by metasomatism from the Akatani ore deposit were observed by high resolution electron microscope. Clinopyroxenes transformed into triple and double chain silicates (fibrous amphibole-like aggregates), and then to sheet structure (talc) during the metasomatism. Various kinds of fine textures and fine structures were observed in weakly altered clinopyroxenes and other biopyriboles. From the observations, the knowledge of alteration of clinopyroxene in metasomatism was renewed; that is, the intermediate products in the metasomatism (so called "fibrous amphibole") are the mixture of multistage products (double and triple chain structures, disordered structures of pyriboles, local superstructures and sheet structures) in local and nonequilihrium reaction.
