Figure F66. A 3- to 5-mm-thick micritic sediment and sparry calcite vein in Sample 192-1185B-5R-3 (Piece 1A, 32-34 cm). Approximately 95% of the wall rock on both sides of the vein is replaced by brownish tan smectite forming 2- to 4-mm-wide brown halos. Total replacement of the olivine phenocrysts and groundmass glass by smectite brings the overall alteration of the host rock to 15%-20%. Plagioclase and clinopyroxene are unaltered (field of view = 5.5 mm; plane-polarized light; photomicrograph ID# 1185B

Figure F66. A 3- to 5-mm-thick micritic sediment and sparry calcite vein in Sample 192-1185B-5R-3 (Piece 1A, 32-34 cm). Approximately 95% of the wall rock on both sides of the vein is replaced by brownish tan smectite forming 2- to 4-mm-wide brown halos. Total replacement of the olivine phenocrysts and groundmass glass by smectite brings the overall alteration of the host rock to 15%-20%. Plagioclase and clinopyroxene are unaltered (field of view = 5.5 mm; plane-polarized light; photomicrograph ID# 1185B_192).