Computer-assisted determination and presentation of crystallographic orientations of plagioclase, on the basis of universal-stage measurements.

Fortran IV subroutines are presented for the manipulation of U-stage measurements on plagioclase. On the basis of two measured indicatrix axes and one crystallographic plane (either (001) or (010)), additional crystallographic planes and directions, and the Au content, are determined; inverse pole figures may also be produced. The influences of inaccurate measurements and multiple solutions on the procedures and possible counter measures are discussed. These subroutines are especially designed for statistical texture analysis of plagioclase. -R.A.H.