Big Obsidian Flow

October 21, 2020



Photographer: Peggy Riemer
Summary Authors: Peggy Riemer, Stu Witmer

The Big Obsidian Flow in Oregon's Newberry National Volcanic Monument dates back 1,300 years and is Oregon's youngest volcanic flow. About 20 miles (32 km) southeast of Bend, Oregon, Newberry is one of the largest volcanoes in the Cascade Range, standing 3,600 feet (1,097 m) above the landscape and encompassing an area of more than 500 square miles (1,300 sq km) with over 400 cinder cones.

Research indicates intermittent human activity here for more than 10,000 years. Obsidian, natural glass that's usually black and formed from quickly cooling lava, was regularly quarried and used to make stone tools and weapons. The caldera was later named Newberry Crater in honor of Dr. John Strong Newberry, the geologist who accompanied the 1885 Williamson-Abbott Expedition Pacific Railroad Survey.