Figure F18. Photomicrograph of the white tephra layer (Sample 205-1253A-4R-3, 85-93 cm). Note the fresher vesicular glass shard surrounded by more altered glass shards that are largely transformed to palagonite.

Figure F18. Photomicrograph of the white tephra layer (Sample 205-1253A-4R-3, 85-93 cm). Note the fresher vesicular glass shard surrounded by more altered glass shards that are largely transformed to palagonite.