Deformation microstructures of the quartz in quartz schist from the Sambagawa metamorphic belt in central Shikoku

Abstract

In the Asemi River region of the Sambagawa metamorphic belt, central Shikoku (Fig.1), dozens of quartz schist layers are intercalated, in which well-defined quartz c-axis fabrics penetratively developed. In this pictorial, we show the close relationship between microstructures and c-axis fabrics in the deformed quartz, which indicates that both the microstructures reflect the deformation geometries caused by ductile flow in the Sambagawa metamorphic belt.The geological structure in the region is characterized by E-Wtrending and Ndipping foliation (Sb), and horizontal mineral lineation (Lm). ThesamplesforFigs.2, 3, 4 and 5 are collected respectively from the metamorphic zones as shown in Fig.1. In all the figures, X, Y and Z directions denote the directions parallel to Iineation, parallel to foliation and normal to lineation, and normal to foliation, respectively, and thesedirections can be approximated as the principal directions of strain ellipsoid(X>Y>Z).