Question

he diagram below represents a stack of rock layers. These layers have not changed position since they formed. Examine the diagram, and answer the question that follows.


If the age of layer 4 is 400 million years and the age of layer 1 is 500 million years, then the age of layer 3 is
A.
older than 500 million years.
B.
500 million years.
C.
between 400 million and 500 million years.
D.
younger than 400 million years.

Answer 1

C. between 400 million and 500 million years.

Explanation: In an undisturbed sequence, the law of superposition says younger layers lie above older ones. If layer 1 is 500 Ma and layer 4 is 400 Ma, layer 3 sits between them and must have formed between those times.