Great Unconformities of the Grand Canyon
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| This image of the Great Unconformity was taken looking northwest from the South Kaibab Trail along Cedar Ridge(Topozone). The Grand Canyon Supergroup is missing from this view but preserved just to the east (below). The dark metamorphic rock of the Vishnu basement has a much different appearance than the layered rocks above, which include the Tapeats Sandstone, Bright Angel Shale, Mauve Limestone and Temple Butte Formation (limestone). Locate the unconformity (type=nonconformity) and the boundaries between layered formations above. Rollover the image with your cursor to check your interpretation. Read about the stratigraphic formations > Stratigraphy of Grand Canyon National Park. What characteristics did you use to locate the boundaries between formations in this image? |
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Further along the South Kaibab Trail both unconformities are seen bordering a locally preserved wedge of the Grand Canyon Supergroup. The Greatest Unconformity separates the Vishnu basement from the gently tilted layers of the Grand Canyon Supergroup. The Great Unconformity lies between the Grand Canyon Supergroup and the Lower Paleozoic section of the Grand Canyon. Block faulting and erosion Grand Canyon Supergroup during the Precambrian is responsible for its uneven distribution. Read Grand Canyon Supergroup Six Unconformities Make One Great Unconformity A Record of Supercontinent Assembly and Disassembly (Grand Cayon River Guides) for a more in depth discussion.
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