High resolution electron microscopic observation of a new kind of superstructure in altered clinopyroxene

Abstract

A new kind of superstructure composed of single and double chains was found by high resolution electron microscopy in hydrothermally altered clinopyroxene from Akatani mine in Niigata Prefecture, Japan. The superstructure of 13.5A was most reasonably interpreted as regular alternation of one single chain and one double chain and that of 31.5A as regular alternation of one single chain and three double chains in the b direction. The regions of 13.5A and 31.5A extend to the b direction about 100∼1000A and 150∼200A in width respectively. Disordered structures composed of single and double chains were also often found.