Figure F37. Close-up photograph of fine-grained basalt from Unit 3 cut by two generations of fractures (interval 200-1224F-13R-2 [Piece 11, 68.5-75.5 cm]). The older fractures are filled with iron oxyhydroxides and are bounded by alteration zones that form halos around fresher centers in each fracture-bound subdomain in the specimen. A second generation of calcite veins rims the left margin of the piece and forms an array of diagonal fractures extending into the center of the piece.

Figure F37. Close-up photograph of fine-grained basalt from Unit 3 cut by two generations of fractures (interval 200-1224F-13R-2 [Piece 11, 68.5-75.5 cm]). The older fractures are filled with iron oxyhydroxides and are bounded by alteration zones that form halos around fresher centers in each fracture-bound subdomain in the specimen. A second generation of calcite veins rims the left margin of the piece and forms an array of diagonal fractures extending into the center of the piece.