Principles of Relative Dating-II

Imagine a rock layer A, which is cut by another rock layer B. How do we calculate which rock is younger?

To solve this question, we can use the principle of cross-cutting relationships. This principle states that any rock layer that cuts across another is younger than the layers it disrupts.

According to this, layer B, which cuts layer A, is the younger layer.

Sometimes, we can see gaps in the rock layers called unconformities. These gaps occur when rock layers are eroded before new layers are deposited.

One of the most famous examples of an unconformity is Hutton's Unconformity in Scotland, discovered by James Hutton, known as the "Father of Modern Geology.

He observed that the tilted ancient rock layers are overlain by younger horizontal layers, showing a significant time gap.

He determined that over time, the old rocks were deposited, uplifted and tilted. Some of the rocks were then eroded away and new sediments were deposited on top.Since the processes of deposition, erosion, and tilting take immense amounts of time, he realized that Earth is much older than what scientists thought.