Which of the following is true about the age of rock layers and the age of the Earth? A. The top layer in a sequence of rock layers is older than the Earth. B. All rock layers are older than the Earth. C. The Earth is older than any rock layer. D. The bottom layer in a sequence of rock layers is older than the Earth.

The Earth is older than any rock layer.

Explanation:

The rock layers on our planet are numerous, and each of them represents a particular geological period. They occupy anywhere between 25 and 70 km in-depth, or rather the uppermost layer of our planet. And while some of these rock layers are over a billion years of age, they are not older than Earth. Earth has initially formed from a nebula, space dust, which over time consolidated, and it took at least a couple of billions of years for the first rocks to occur.

The rocks only started to form when the conditions were right on the surface, or basically when Earth cooled enough so that the magma can cool down and solidify. Since the formation of the first rocks, the process has not stopped, and there is the constant formation of new ones, pilling on top of the older layers. It is not just that new rocks are forming though, but older rocks are getting subducted and end up in the mantle where they melt and get recycled.