Figure F28. Miarolitic cavity in basalt filled with brown smectite (brown to tan), calcite (white with two cleavages), and minor goethite (dark brown to black) in Sample 192-1187A-5R-4 (Piece 5, 91-94 cm). The wall rock around the miarolitic cavity is pervasively replaced by brown smectite. Plagioclase outside the alteration halo is only partially altered (field of view = 5.5 mm; plane-polarized light; photomicrograph ID# 1187A

Figure F28. Miarolitic cavity in basalt filled with brown smectite (brown to tan), calcite (white with two cleavages), and minor goethite (dark brown to black) in Sample 192-1187A-5R-4 (Piece 5, 91-94 cm). The wall rock around the miarolitic cavity is pervasively replaced by brown smectite. Plagioclase outside the alteration halo is only partially altered (field of view = 5.5 mm; plane-polarized light; photomicrograph ID# 1187A_259).