1 mm), and subhedral. Original olivine phenocrysts were also scarce (<1%) and equant (1–2 mm) crystals.
Volcanic basement was recovered from Holes SEG70A and SEG71A, representing a total of 0.98 m. Hole SEG70A sampled a vesicular and amygdaloidal, highly plagioclase-clinopyroxene-olivine phyric and glomerophyric basalt with a fine-grained groundmass of plagioclase, clinopyroxene, olivine, and Fe-Ti oxide minerals. The groundmass is moderately altered, whereas olivine phenocrysts are completely replaced by iddingsite, lizardite, and/or clay. Unit I-1 shows typical intersertal texture (Fig.
F4A). Plagioclase phenocrysts composed 20% by volume and have tabular morphology with long dimensions of 2–5 mm. Clinopyroxene phenocrysts are scarce (<2%), small (1 mm), and subhedral. Original olivine phenocrysts were also scarce (<1%) and equant (1–2 mm) crystals.
Unit I-1 from Hole SEG71A is a fine- to medium-grained, nonvesicular diabase with subophitic texture (Fig. F4B). Plagioclase forms 0.2- to 1.5-mm interlocking laths composing up to 50% of the rock, whereas clinopyroxene are 0.2- to 1.5-mm subhedral grains making up 33% the rock. The remaining assemblage is Fe-Ti oxide minerals (4%), altered mesostasis (5%), and completely replaced olivine (<1%).
