写真素材 - The Navajo Volcanic Field in the Four Corners area of the American southwest has about 80 old, eroded volcanic centers (volcanic necks/volcanic plugs/diatremes) of Oligocene to Miocene age.
The Navajo Volcanic Field in the Four Corners area of the American southwest has about 80 old, eroded volcanic centers (volcanic necks/volcanic plugs/diatremes) of Oligocene to Miocene age.