Figure F26. Photomicrograph showing networks of fine-grained chlorite-sericite-amphibole developed locally in fresh olivine-bearing dunite. Locally these assemblages replace primary minerals, possibly plagioclase or pyroxene. In contrast, olivine crystals are entirely fresh and show sharp boundaries to the chlorite-sericite-amphibole alteration assemblages (Sample 209-1271B-10R-1, 40–43 cm) (cross-polarized light: blue + dark gray filters; field of view = 5.5 mm; image 1271B

Figure F26. Photomicrograph showing networks of fine-grained chlorite-sericite-amphibole developed locally in fresh olivine-bearing dunite. Locally these assemblages replace primary minerals, possibly plagioclase or pyroxene. In contrast, olivine crystals are entirely fresh and show sharp boundaries to the chlorite-sericite-amphibole alteration assemblages (Sample 209-1271B-10R-1, 40–43 cm) (cross-polarized light: blue + dark gray filters; field of view = 5.5 mm; image 1271B_029).