Grand canyon relative dating cross section
Therefore, the youngest layers are found at the top, and the oldest layers are found at the bottom of the sequence.
This nicely illustrates the principle of original horizontality.
If a sedimentary rock is found tilted, the layer was tilted after it was formed.
Sediments were deposited in continuous sheets that spanned the body of water that they were deposited in.
Based on the principle of cross-cutting relationships, the river must be younger than all of the rock layers that it cuts through.
The relative age of a rock is its age in comparison with other rocks.
The youngest rock layers are at the top of the canyon, while the oldest are at the bottom, which is described by the law of superposition.