Sample from short lava flow, possibly 1883. Plagioclase, hypersthene, augite, olivine, and relict hornblende phenocrysts in a holocrystalline groundmass of plagioclase microlites, pyroxenes, and Fe-Ti oxides. Hornblende is completely recrystallized to fine-grained Fe-Ti oxide+plagioclase+pyroxene. Olivine is surrounded by a faint dusty rim. Groundmass contains lighter patches or bands with similar mineralogy to the rest of the groundmass but having a smaller proportion of Fe-Ti oxide.
Petrology, geochemistry, and the evolution of magmas from Augustine Volcano, Alaska