Figure F100. A. Close-up photograph of saponite-rich dark alteration patches in dark gray pervasively altered basalt (interval 206-1256D-26R-3, 15-45 cm). B. Close-up photograph of dark gray pervasively altered basalt, cut by a network of saponite, silica, and iron oxyhydroxide-bearing veins, some with mixed alteration halos. Vugs are filled with silica and saponite, which also form dark alteration patches (interval 206-1256D-27R-2, 40-62 cm).

Figure F100. A. Close-up photograph of saponite-rich dark alteration patches in dark gray pervasively altered basalt (interval 206-1256D-26R-3, 15-45 cm). B. Close-up photograph of dark gray pervasively altered basalt, cut by a network of saponite, silica, and iron oxyhydroxide-bearing veins, some with mixed alteration halos. Vugs are filled with silica and saponite, which also form dark alteration patches (interval 206-1256D-27R-2, 40-62 cm).