Photometric Determination of Preferred Orientation of Feldspars in Fine-Grained Igneous Rocks

Abstract

The crystal habit and optical orientation of many feldspars combine to provide a convenient means for determining shape orientation form optical data. Results from photometric determinations of five different units show that it is possible to deduce, within narrow limits, major flow patterns producing planar orientation in certain fine-grained igneous rocks.  It may be possible to determine the direction of flow from such a technique.