An extraordinarily beautiful river canyon lay where today’s Lake Powell shimmers. There was nothing else like it on earth with its isolation, twisting and mysterious side canyons, Indian ruins, and gentle, idyllic landforms. But, in the mid-1950s, …
The Back Story
Just downstream from Glen Canyon lies Grand Canyon, a somewhat better known segment of Colorado River canyon. Grand Canyon is a profound cleft in Earth’s crust that almost always prompts questions about its creation; how long ago did it form and why …
Glen Canyon Rock Layers
Glen Canyon area rocks were laid down during the Mesozoic Era, a period of time that followed the interval when all Grand Canyon rock units were created. The Mesozoic Era lasted about 170 million years, from 251 to 65 million years ago. Some …
Monoclines
The Colorado Plateau is characterized by a thick sequence of mostly sedimentary rock layers that have been uplifted thousands of feet by plate tectonics movements. The uplift began about 70 million years ago, thus ending almost all sedimentary rock …
Glen Canyon’s Prominent Rock Units: The Aeolian Sandstones Plus One
Throughout the middle and downstream sections of Lake Powell about a dozen rock units can be seen. All are sedimentary in origin. Of these, only about four are exceptionally prominent, and three of them are Aeolian (wind-deposited) sandstones. The …
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