Newberry Volcano obsidian

Newberry Volcano obsidian comes from flows inside the caldera of the huge Newberry shield volcano in central Oregon, about 40 miles east of the Cascade crest. The Newberry type is a set of chemically identical flows (Interlake, Central Pumice Cone, Game Hut and East Lake) erupted between about 7,000 and 3,000 years ago, after Mount Mazama's ash buried the caldera. The caldera's middle and late Holocene sites are almost all quarry stations and workshops with huge amounts of reduction debris and large bifacial blanks, a scale that suggests a commercial operation. Newberry glass was carried mostly north down the Deschutes basin to the trading center at The Dalles and on to the Salish Sea region, but little went south.

Obsidian flows inside Newberry Caldera, Deschutes County: the Interlake, Central Pumice Cone, Game Hut and East Lake flows (about 7,000 to 3,000 years old) make up the Newberry Volcano chemical type. Chemically distinct flows (Buried Flow and the Big Obsidian Flow, erupted about 1,300 years ago) rarely occur beyond the caldera. Moore's guide calls the Newberry flow reputed to be the largest single obsidian flow in the world.