Figure F50. Typical zoned felsic vein in Sample 176-735B-90R-1 (Piece 1C, 37-60 cm). The vein contains an amphibole- and clinopyroxene-rich core, with a plagioclase- and quartz-rich margin. There is a weakly developed halo at the vein margin associated with alteration of plagioclase and pyroxene in the wall rock to secondary plagioclase and amphibole, respectively.