| Text Description: |
Flow immediately overlying stratified drift. At the base and top of the flow is palagonite-rick breccia that may have interacted with water causing small steam explosions. The flow is at the base of the middle andesite package at Site 1 in the Boyden Hills. Fine-grained, vesicular, diktytaxitic, hypocrystalline, intersertal, intergranular, trachytic, porphyritic to glomeroporphyritic with a matrix of brown glass, opaque, plagioclase, and clinopyroxene. Plagioclase phenocrysts (An45-An63) are up to 2.2 mm, often have sieve textured cores, frequently have normal zoning and occasionally have oscillatory zoning. Olivine phenocrysts are up to 1.12 mm and some have opaque inclusions or occasional alteration along the rim; one grain has a rim of small orthopyroxene crystals. Clinopyroxene phenocrysts up to 0.6 mm. Orthopyroxene phenocrysts are up to 0.9 mm and occasionally have clinopyroxene rims. |