Quartz c-axes orientation determination using the rotating polarizer microscope

A fast and accurate optical method to calculate quartz c-axis orientations using the rotating polarizer stage and standard thin sections is presented. c-Axis orientations are calculated for each pixel and Achsenverteilungsana lyse (AVA) can easily be constructed to study problems that would normally require a prohibitive amount of tedious work. The computer controlled rotat ing polarizer stage replaces the polarizer and analyzer of the standard pet rographic microscope and allows a thin section to remain fixed while the po larizing filters are rotated by stepper motors. Data are collected by stepp ing the polarizers through a 180 degrees rotation, capturing a frame at eac h step and extracting information on the intensity of the pixel and positio n of the polarizers. The position data are used to calculate the trend or t rend + 180 degrees of the quartz c-axes, while a simple mathematical relati onship between intensity and plunge is derived which allows the plunges of c-axes to be calculated. (C) 2001 Elsevier Science Ltd. All rights reserved .