| Text Description: |
Blotched and streaky hornblende andesite lava, with some strands of light brownish-gray (5YR 7/1) and others medium light gray (N6). Texture seriate, with conspicuous crystals of plagioclase and hornblende up to 2 mm, sparser and smaller crystals of augite and olivine up to 0.2 mm. The median composition of the coarser plagioclase crystals is about An58. The hornblende is typical "basaltic" hornblende, with small extinction angle, and is pleochroic from red-brown to yellow. The maximum index of about 1.743 and the minimum index about 1.678. The salite has nX 1.68, suggesting about Ca60Mg40Fe10. Accessories include apatite, as pseudodichroic stubby prisms, and magnetite. Much hematitic dust is present in the groundmass, which consists principally of anhedral oligoclase (?), tridymite (?), magnetite, and needles of augite. |