The matrix has a poikiloophitic texture formed predominantly by plagioclase (labradorite, [An.sub.60-65], in some grains bytownite
, [An.sub.70-75]) enclosed by elongated hypidiomorphic brownish augite crystals of 0.3-0.8 mm length and isometric grains of subordinated olivine and biotite; accessory phases are apatite and magnetite.
The main minerals in the pillow-lava are olivine (varies between chrysolite to hyalosiderite), Ti-augite, plagioclase (variable from bytownite
to oligoclase) and minoritary biotite, Ti-hornblende, apatite and Fe-Ti oxides (Puga et al., 1989; Morata et al., 1996).
Plagioclase phenocrysts (bytownite
or labradorite; [An.sub.64-72]) have rims that are both similar to, and more sodic than, the calcic cores, with some solid solution variation within the cluster.
Quartz, graphite, pyrite, grossular, diopside, bytownite
, dolomite and calcite are the most common associations.