Question

In layers of rock, the rock on the bottom layer is what?

Answer 1

The rock on the bottom layer of a rock formation is usually the oldest, as it was formed first and then covered by subsequent layers of rock over time. This is due to the principle of superposition, which states that in an undisturbed sequence of layers, the oldest layer is at the bottom and the youngest layer is at the top.

Answer 2

According to the Principle of Superposition (as stated in search result [10]), in an otherwise undisturbed sequence of sedimentary strata , or rock layers, the layers on the bottom are the oldest. Therefore, in layers of rock, the rock on the bottom layer is the oldest.