According to the law of superposition, which statement is true?

According to the law of superposition, which statement is true?

• A. Younger rocks are located deeper in the sequence.
• B. Deep layers are formed from the surface downward.
• C. Deeper rock layers are generally older than shallower layers.
• D. Fossils in deeper layers are always younger.

Answer: (C)

In an undisturbed stack of sedimentary rocks, older material settles first and remains at the bottom as new layers accumulate on top over time. This means deeper rock layers are generally older than shallower ones, which is the essence of the law of superposition. The statement fits this pattern: the deeper you go, the older the layers tend to be. If a sequence has been disturbed by events like tilting, folding, faulting, erosion, or intrusion, the simple bottom-to-top order may not hold, but the basic idea remains the same for undisturbed sections. The other options contradict how layers are laid down: younger rocks appearing deeper would reverse the deposition order, claiming deep layers form from the surface downward misstates how layering develops, and saying fossils in deeper layers are always younger ignores situations where geological processes relocate or rework material.

In an undisturbed stack of sedimentary rocks, older material settles first and remains at the bottom as new layers accumulate on top over time. This means deeper rock layers are generally older than shallower ones, which is the essence of the law of superposition. The statement fits this pattern: the deeper you go, the older the layers tend to be.

If a sequence has been disturbed by events like tilting, folding, faulting, erosion, or intrusion, the simple bottom-to-top order may not hold, but the basic idea remains the same for undisturbed sections. The other options contradict how layers are laid down: younger rocks appearing deeper would reverse the deposition order, claiming deep layers form from the surface downward misstates how layering develops, and saying fossils in deeper layers are always younger ignores situations where geological processes relocate or rework material.