
Tephra from Mt. Mazama's Climactic Eruption
It was one of Oregon’s highest peaks, over 12,000’ in elevation. It was taller than Mt. Hood and more massive than Mt. Jefferson. But in a matter of hours 7,700 years ago, it disappeared in one cataclysmic explosion, sending ash deposits as far away as Canada and hot pumice flows hundreds of feet thick up to 25 miles from today’s Crater Lake. The distinctive, white-colored signature layer of these tephra deposits can be found throughout Central Oregon today, revealing itself at trailside or on riverbanks when least expected.