Figure F28. Close-up photograph of a black, magnetite-rich domain that is hosted within a vesicular to amygdaloidal aphyric volcanic groundmass. The origin of these domains is uncertain; however, it is apparent that particular parts of the rock provided more favorable conditions for hydrothermal fluid flow and magnetite precipitation than others (interval 193-1188F-34Z-1, 63-70 cm).

Figure F28. Close-up photograph of a black, magnetite-rich domain that is hosted within a vesicular to amygdaloidal aphyric volcanic groundmass. The origin of these domains is uncertain; however, it is apparent that particular parts of the rock provided more favorable conditions for hydrothermal fluid flow and magnetite precipitation than others (interval 193-1188F-34Z-1, 63-70 cm).