Figure F53. Basalt showing total replacement of small olivine phenocrysts, skeletal elongate olivine crystals, and glassy groundmass by smectite and Fe oxyhydroxide in Sample 192-1185B-5R-8 (Piece 3, 31-33 cm). The photomicrograph is of a light yellow-brown zone cut by parallel, subhorizontal veins of calcite (not visible). Plagioclase and clinopyroxene are unaltered (overall alteration = 25%-30%; field of view = 1.4 mm; plane-polarized light; photomicrograph ID# 1185B

Figure F53. Basalt showing total replacement of small olivine phenocrysts, skeletal elongate olivine crystals, and glassy groundmass by smectite and Fe oxyhydroxide in Sample 192-1185B-5R-8 (Piece 3, 31-33 cm). The photomicrograph is of a light yellow-brown zone cut by parallel, subhorizontal veins of calcite (not visible). Plagioclase and clinopyroxene are unaltered (overall alteration = 25%-30%; field of view = 1.4 mm; plane-polarized light; photomicrograph ID# 1185B_194).