Figure F37. Close-up photograph of Sample 183-1140A-34R-3 (Piece 1, 77-90 cm). Sharp boundary between gray basalt and an oxidized orange-brown alteration halo related to the underlying contact with dolomitized chalk. The most intense coloration in this halo is at the boundary. The ~1-mm vein that cuts this boundary changes from light green clay to brown clay (± iron oxyhydroxides).