| Text Description: |
Third flow from the bottom of the lower andesite package at Site 1 in the Boyden Hills. Fine-grained, vesicular, hypocrystalline intergranular, intersertal, seriate to glomeroporphyritic with a matrix of brown glass, mesostasis, opaques, plagioclase, clinopyroxene and alteration. Plagioclase phenocrysts (An41-An58) are up to 2.03 mm, and commonly have sieve textured cores with overgrowth rims, normal zoning; occasionally have oscillatory zoning. Olivine phenocrysts are up to 0.75 mm, may be partially or completely altered, and tend to have corroded rims. Clinopyroxene phenocrysts are up to 1.75 mm. Orthopyroxene phenocrysts are up to 0.85 mm and some have clinopyroxene rims. |