Figure F231. Petrographic features of Unit 1256D-82. A. Granophyric intergrowth of plagioclase (plag) and quartz (qtz) in quartz-bearing oxide diorite of Unit 1256D-82 (Thin Section 60; Sample 312-1256D-214R-1, 41–47 cm) (field of view [FOV] = 0.6 mm; cross-polarized light). Actinolite (act) replaces primary amphibole or clinopyroxene in the greenish domains at the edges of the image. B. Relict primary brownish green hornblende (hbl) displaying basal cleavage surrounded by pale green actinolite in a quartz-bearing oxide diorite (Thin Section 60; Sample 312-1256D-214R-1, 41–47 cm) (FOV = 0.6 mm; plane-polarized light). C. Relict primary brown hornblende flakes within aggregates of pale green actinolite in a quartz-bearing oxide diorite (Thin Section 60; Sample 312-1256D-214R-1, 41–47 cm) (FOV = 0.6 mm; plane-polarized light). D. Twinned, elongate prismatic relict amphibole replaced by actinolite (diagonal top right to lower left) and granophyric intergrowths (directly below amphibole) of altered plagioclase and quartz in the quartz-bearing oxide diorite from Unit 1256D-82 (Thin Section 60; Sample 312-1256D-214R-1, 41–47 cm) (FOV = 4.8 mm; cross-polarized light).
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