Figure F10. Representative X-ray diffractograms showing unaltered and altered volcanic ash at Site 1174. The unaltered ash sample displays a highly elevated baseline due to amorphous glass shards and minor amounts of quartz, plagioclase, and halite (Sample 190-1174B-37R-2, 131-137 cm). Common alteration products with deeper burial of the ash include smectite (e.g., Sample 190-1174B-84R-5, 77-78 cm) and undifferentiated clinoptilolite/heulandite (e.g., Sample 190-1174B-54R-7, 27-28 cm).