An ultimate steady-state pattern of c-axis fabric of quartz in metamorphic tectonites

Abstract

The c-axis fabrics of quartz grains at the hinge zones of the orthorhombic buckle folds of quartz-rich layers which were collected from the Sambagawa crystalline schists of Shikoku, Japan, have been described and discussed. Especially, attempt to correlate the pattern of the quartz fabric with the strain picture has been made. It has been pointed out that the high concentration of quartz axes on two positions which are symmetrically placed on the plane of the longest principal axis and the shortest principal axis of the strain ellipsoid and at an angle of ca. 30‡ to the latter axis may be regarded as an ultimate steady-state pattern of preferred orientation of quartz axes developed under non-rotational two dimensional strain.