Medium gray scoria ; Tallus below the 2016-2017 extrusive dome; Scoria (20% vesicularity) with medium gray mostly crystalline groundmass and <1% hornblende to 1 mm, 5% plagioclase to 2 mm, <1% pyroxene to 1 mm. Vesicles coated in secondary mineral.
Petrology of the 2016-2017 eruption of Bogoslof Island, Alaska
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