I’m not sure whether a debate about the age of the earth has taken place in recent times without any reference being made to the Grand Canyon. Most scientists claim that it must have taken many years to form, but those who believe in a young earth claim that it could have been formed quickly. These people point primarily to two known facts: Large floods can deposit layers of sediment, and canyons can form quickly. Using this information, they conclude that a global flood could have created all (or most) of the rock layers seen in the canyon and that a large flash flood caused by a dam bursting shortly after the flood could have carved out the canyon itself. Does this explanation hold water (pun intended)? What are the facts concerning the Grand Canyon, and are they compatible with formation by a global flood? Today I will address the formation of the rock layers seen in the Grand Canyon, and next time I will address the formation of the canyon itself.
Nobody disputes that floods can and often do deposit layers of sediment. However, a more specific question is warranted: Could the particular types and sequence of rock layers found in the Grand Canyon have been formed by a single flood event? This is a question that I have never heard young-earth creationists address.
The young-earth creationists typically point out that if you shake up a jar of muddy water and let it settle, it will form layers according to the densities of the suspended particles. They claim that this is how rock layers formed in the flood. It is true that floods can form layers in this manner. The coarsest sediments end up on the bottom, and the finest sediments end up on the top. However, this is not what we observe in the layers of rock found in the Grand Canyon area.
You see, the top layer of rock in the Grand Canyon area is limestone (#1 in the diagram). Beneath that is a layer of sandstone (#3). Beneath the sandstone is siltstone (#4), and beneath the siltstone is more limestone (#7). If these layers were all formed at the same time by settling of particles after a global flood, then we should expect the sand to have settled before the silt. It should not be possible in this context for a sandstone layer to form on top of a siltstone layer. Also, it should not be possible for these to be sandwiched between different layers of limestone.
Limestone is a type of rock that can form only in a marine environment, and both layers of limestone (#1 and #7) contain numerous marine fossils. Sandstone can be formed either on land or underwater. However, the sandstone (#4) in between these two layers of limestone could not possibly have formed underwater. It contains no fossils of marine organisms. Also, it contains numerous fossil tracks, including reptile tracks and also tracks from small arthropods such as centipedes and spiders. It also contains raindrop impressions. These cannot be formed underwater.
So the evidence clearly points to this: The land was submerged under water for some time. At some point after this, it became a sandy desert. After this, it was again submerged under water for a long enough time to form several hundred feet of additional limestone. I simply cannot figure out how this can be explained by a single global flood. I have searched the internet and cannot find even a single source that attempts to explain this.
If you can explain to me how the specific layers of rock found in the Grand Canyon area could have formed in the observed sequence by a global flood, then please do. Really, I mean it. I’m dying to understand this.