Figure F109. Photomicrographs showing pyrite front lining the boundary between a black halo and the adjacent dark gray slightly altered host rock. A. Sample 206-1256D-13R-1, 109-111 cm (field of view = 10 mm; reflected light). B. Sample 206-1256D-35R-3, 11-12 cm (field of view = 10 mm; plane polarized light). C. Sample 206-1256D-35R-3, 11-12 cm (field of view = 10 mm; reflected light).

Figure F109. Photomicrographs showing pyrite front lining the boundary between a black halo and the adjacent dark gray slightly altered host rock. A. Sample 206-1256D-13R-1, 109-111 cm (field of view = 10 mm; reflected light). B. Sample 206-1256D-35R-3, 11-12 cm (field of view = 10 mm; plane polarized light). C. Sample 206-1256D-35R-3, 11-12 cm (field of view = 10 mm; reflected light).