Figure F20. A. Close-up photograph of interval 209-1272A-23R-1, 62-70.5 cm. B. XRD spectrum of interval 209-1272A-23R-1, 67–69 cm (arrow indicates the approximate position of the analyzed powder). Note the positive identification of serpentine, magnetite, brucite, and iowaite. See text for discussion.

Figure F20. A. Close-up photograph of interval 209-1272A-23R-1, 62-70.5 cm. B. XRD spectrum of interval 209-1272A-23R-1, 67–69 cm (arrow indicates the approximate position of the analyzed powder). Note the positive identification of serpentine, magnetite, brucite, and iowaite. See text for discussion.