Figure F24. Close-up photograph of plagioclase-phyric volcanic rock of Unit 41. Individual 1- to 2-cm-wide zones with fragmental textures are present in several adjacent pieces of Unit 41. These zones are compositionally identical to the coherent volcanic rock on either side. It is inferred that these zones may be the product of autobrecciation during flow or brecciation caused by faulting. Note the lath-shaped plagioclase phenocrysts; one phenocryst is dissected by an anhydrite-pyrite veinlet (arrow) (interval 193-1188F-14Z-1, 16.5-35.5 cm).

Figure F24. Close-up photograph of plagioclase-phyric volcanic rock of Unit 41. Individual 1- to 2-cm-wide zones with fragmental textures are present in several adjacent pieces of Unit 41. These zones are compositionally identical to the coherent volcanic rock on either side. It is inferred that these zones may be the product of autobrecciation during flow or brecciation caused by faulting. Note the lath-shaped plagioclase phenocrysts; one phenocryst is dissected by an anhydrite-pyrite veinlet (arrow) (interval 193-1188F-14Z-1, 16.5-35.5 cm).