Question #bc134
1 Answer
Feb 28, 2018
Intrusions are younger. Look for alteration of sedimentary rock from the hot intrusion. Also look for cross-cutting relationships.
Explanation:
The sedimentary layers would have to be in place BEFORE the igneous intrusion formed, otherwise the intrusion would have spilled out on the surface as a lava flow. Therefore, igneous intrusions are usually younger. Look for altered minerals in the sedimentary rock due to the hot intrusion. Also, younger intrusions will cross-cut older/existing layers.