Sample of 1976 dome. Plaioclase, hypersthene, augite, Cr-spinel bearing olivine, and Fe-Ti oxides phenocrysts in a groundmass composed of plagioclase microlites, minor pyroxenes, and Fe-Ti oxides with a trace of clear interstitial glass. Olivine is oxidized along fractures and is rimmed by fine grained plagioclase+oqaue phases+pyroxene. Hornblende occurs as rare smal (0.05 mm) inclusions in olivine.
Petrology, geochemistry, and the evolution of magmas from Augustine Volcano, Alaska