Figure F10. Chemical map showing variations of (A) Al and (B) Na in large, zoned plagioclase crystals in a plagioclase-rich vein (Sample 176-735B-161R-7, 77-83 cm). The vein margin in the lower right (delineated by solid black line) is marked by a distinct change in plagioclase composition from calcic plagioclase (An) in the host rock to more sodic plagioclase (Pl) in the vein. The large, subhedral plagioclase crystals in the vein have relatively uniform cores and strongly zoned, relatively sodic rims. The spaces between the plagioclase grains may be open or filled with minor amphibole or quartz. Scale bars = 5 mm.

Figure F10. Chemical map showing variations of (A) Al and (B) Na in large, zoned plagioclase crystals in a plagioclase-rich vein (Sample 176-735B-161R-7, 77-83 cm). The vein margin in the lower right (delineated by solid black line) is marked by a distinct change in plagioclase composition from calcic plagioclase (An) in the host rock to more sodic plagioclase (Pl) in the vein. The large, subhedral plagioclase crystals in the vein have relatively uniform cores and strongly zoned, relatively sodic rims. The spaces between the plagioclase grains may be open or filled with minor amphibole or quartz. Scale bars = 5 mm.