Figure F13. Close-up photograph showing a light-colored altered volcanic ash layer within the background sedimentation of claystone with zeolites (interval 205-1253A-4R-3, 82-94 cm). High degree of alteration and induration may reflect proximity to the gabbro sill of lithostratigraphic Subunit U4B, which lies slightly >2 m below the bed.

Figure F13. Close-up photograph showing a light-colored altered volcanic ash layer within the background sedimentation of claystone with zeolites (interval 205-1253A-4R-3, 82-94 cm). High degree of alteration and induration may reflect proximity to the gabbro sill of lithostratigraphic Subunit U4B, which lies slightly >2 m below the bed.