Sample of Kamishak dome. Plagioclase, hornblende, hypersthene, augite, olivine, and minor Fe-Ti oxide phenocrysts in a fine grained holocrystalline groundmass of plagioclase microlites, Fe-Ti oxides, and pyroxenes. Hornblende is euhedral to subhedral, opacite-rimmed, and occasionally being replaced by hypersthene. This sample contains several xenoliths with similar mineralogy but very little groundmass. Hornblende in these xenoliths is very elongate and average grain size is smaller than in the host.
Petrology, geochemistry, and the evolution of magmas from Augustine Volcano, Alaska