What does the law of superposition state?

The law of superposition is a fundamental principle in geology and sedimentology that states that in an undisturbed sequence of sedimentary rock layers, the oldest layers are found at the bottom, while the younger layers are deposited on top. This means that if you were to examine a column of sedimentary rocks, you would expect to see the oldest sediments at the bottom and progressively younger sediments as you move up the column.

This principle is key for understanding the relative ages of rock formations and the geological history of an area. It relies on the idea that sedimentary rock layers are deposited in a time sequence, with new material accumulating over older material. Recognizing this pattern helps geologists reconstruct the chronological sequence of geological events and understand the history of the Earth's surface.

The other options do not align with the established principles of geology that the law of superposition encapsulates. For example, the idea that the youngest layers are always on top applies in most cases, but disturbances can lead to exceptions. Similarly, suggesting that all sedimentary layers are of equal age or that their deposition is random contradicts the systematic nature of sediment layering as described by this law.