Madagascar is the world’s oldest island. The first island appears on Earth about 4.4 billion years ago when the ocean formed. The island that has existed longest is Madagascar which separated from India perhaps 85 to 90 million years ago, after the two had split off from Antarctica about 125 million years ago.
Uinkaret volcanic field (NASA photo) on the No.Rim of the Grand Canyon (lava flows are brown). Lava flows from this volcanic field have dammed the Colorado River multiple times from 725,000 to 100,000 yrs ago. One of these cascades is today's 'Lava Falls.' Lava Falls Rapid, below Lava Falls on the Colorado River, is 'at all water levels, the most severe rapid in Grand Canyon.'