| Text Description: |
Not sure if this is a dike, sill or flow. At the top of Site 12. Fine grained, vesicular, holocrystalline, seriate porphyritic with a matrix of mesostasis, opaque, plagioclase, orthopyroxene with clinopyroxene rims, olivine? and clinopyroxene. Plagioclase phenocrysts (An26 - An55) are up to 1.9 mm and the larger grains tend to have sieve textured zones and may be oscillatory zoned, while the smaller laths may have normal zoning. Olivine phenocrysts are up to 1.0 mm and some have skeletal habits, rims of small orthopyroxene crystals, or are partially altered. Orthopyroxene phenocrysts are up to 1.75 mm and some have clinopyroxene rims; a few have resorption embayments. Clinopyroxene phenocrysts are up to 0.1 mm. |