How did these sea floor rocks attain such high elevations? Yet today, at the top of the Colorado Plateau, the Kaibab Limestone is found at elevations up to 9,000 feet. The Kaibab Limestone, the uppermost layer of rock at Grand Canyon, was formed at the bottom of the ocean. The start of the South Kaibab trail shows an abundant display of Kaibab stone. If rock layers appear tilted, that is due to some geologic event that occurred after the rocks were originally deposited.
This means that all the rock layers were laid horizontally. In geology, this is referred to as the principle of superposition, meaning rocks on the top are generally younger than rocks below them.Īnother important principle is the principle of original horizontality. That means that the bottom layer was formed first, and every subsequent layer was formed later, with the youngest rocks on the top. It shows the rock layers with the oldest on the bottom, and the youngest on the top. To look at rock layers, geologists use a diagram called a stratigraphic column. Then, layer upon layer of sedimentary rocks were laid on top of these basement rocks.
The story begins about 2 billion years ago when igneous and metamorphic rocks were formed. The story of how Grand Canyon came to be begins with the formation of the layers and layers of rock that the canyon winds through. Horizontal striations can be found in the walls of the majority of the canyon.
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