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The resulting Grand Canyon Supergroup of sedimentary units is composed of nine varied geologic formations that were laid down from 1.2 billion and 740 million years ago in this sea. [11] Good exposures of the supergroup can be seen in eastern Grand Canyon in the Inner Gorge and from Desert View, Lipan Point and Moran point.
Current archaeological evidence suggests that humans inhabited the Grand Canyon area as far back as 4,000 years ago [1] and at least were passers-through for 6,500 years before that. [2] Radiocarbon dating of artifacts found in limestone caves in the inner canyon indicate ages of 3,000 to 4,000 years. [1]
This increased the rate of erosion and cut nearly all of the Grand Canyon's current depth by 1.2 million years ago. The terraced walls of the canyon were created by differential erosion. [33] Between 100,000 and 3 million years ago, volcanic activity deposited ash and lava over the area, which at times completely obstructed the river. These ...
Within the Grand Canyon, the Great Unconformity represents a period of about 175 million years between the Tonto Group and the youngest subdivision, the Sixtymile Formation, of the Grand Canyon Supergroup. At the base of the Grand Canyon Supergroup, where it truncates the Bass Formation, the period of time represented by this angular ...
The Mesoproterozoic formations in the Grand Canyon are overlain by the 850 million year old, Neoproterozoic Chuar Group and Sixtymile Formation sedimentary rocks. The Great Unconformity is a famous gap in the stratigraphic record of the Grand Canyon of 900 million years between Proterozoic granitic rocks and Cambrian marine sediments. For the ...
The Grand Canyon in Arizona is one of Earth's natural wonders, carved out over millions of years by the gradual erosion power of the Colorado River. Close to the moon's south pole are two canyons ...
Two Grand Canyon-size features on the far side of the moon were likely formed in about 10 minutes after an unknown object slammed into the moon 3.8 billion years ago.
Approximately 35 million years ago, rainfall flowed into the rock, and eroded passages that led to the Colorado River and what is now the Grand Canyon. Millions of years later, the evaporating water left calcium deposits on the walls and floors, creating the formations that can be viewed today.