C 16 - Abert Rim OR31

Abert Rim, some 2,500 feet above the valley floor is one of the highest fault scarps in the United States. This basalt formation, a basic lava covering much of Eastern Oregon, issued from great fissures during the Miocene Period of geologic history many millions of years ago. After this extensive lava flooding, the earth's crust was fractured at many points and great blocks were tilled. Abert Rim is the western edge of one of these tilted blocks while Abert Lake lies on top of another.