Discovering the Age of Rocks with Included Fragments

What can you infer if a sandstone in contact with a granite contains fragments of the granite?

A. The granite is older than the sandstone

B. The sandstone and granite are the same age

C. The granite is younger than the sandstone

D. The granite was intruded into the sandstone

Answer:

The correct answer is A. The granite is older than the sandstone.

Using the principle of included fragments in geology, if a sandstone is in contact with a granite and contains fragments of the granite, it indicates that the granite is older than the sandstone.

Explanation: If a sandstone is in contact with a granite and contains fragments of the granite, then this suggests that the granite is indeed older than the sandstone. This inference is based on the principle of included fragments in geology, which states that any rock fragment included in another rock must be older than the rock it is found in. Therefore, since the sandstone contains fragments of the granite, we can infer that the granite was present first, and was later eroded and became part of the sandstone.

We can rule out option B which suggests that the granite and sandstone are the same age, and option C which suggests that the granite is younger than the sandstone. Option D suggests that the granite was intruded into the sandstone, however, this would result in the granite being younger than the sandstone which contradicts our initial inference. Therefore, the most correct answer is option A: The granite is older than the sandstone.