Figure F88. Photomicrograph showing celadonite and iron oxyhydroxide intergrowth lining the vein walls, followed by chalcedony + iron oxyhydroxide. These phases are in turn followed by aragonite or cut by veinlets of aragonite ± pyrite or by veinlets of chalcedony. In the 0.1- to 0.3-mm-wide alteration halo adjacent to the vein, the basalt is highly to totally altered to pale green clay (ML clay?) ± saponite and titanite. Locally, the pale green clay may line the vein walls. Celadonite + minor saponite replace olivine within 1-2 mm of the vein, and saponite replaces olivine in the host rock (Sample 206-1256C-8R-3, 136-140 cm; field of view = 5 mm; plane polarized light).

Figure F88. Photomicrograph showing celadonite and iron oxyhydroxide intergrowth lining the vein walls, followed by chalcedony + iron oxyhydroxide. These phases are in turn followed by aragonite or cut by veinlets of aragonite ± pyrite or by veinlets of chalcedony. In the 0.1- to 0.3-mm-wide alteration halo adjacent to the vein, the basalt is highly to totally altered to pale green clay (ML clay?) ± saponite and titanite. Locally, the pale green clay may line the vein walls. Celadonite + minor saponite replace olivine within 1-2 mm of the vein, and saponite replaces olivine in the host rock (Sample 206-1256C-8R-3, 136-140 cm; field of view = 5 mm; plane polarized light).