Which of the following geologic principle is directly applicable to an igneous dike found in the Grand Canyon that intrudes over older rocks?
A) The principle of superposition states that a rock must first exist before it can be intruded by a dike
B) The principle of crosscutting relationships states that a rock must first exist before it can be intruded by a dike
C) The principle of original horizontality states that a rock must first exist before it can be intruded by a dike
D) The principle of included fragments states that a rock must first exist before it can be intruded by a dike
E) The principle of faunal succession states that a rock must first exist before it can be intruded by a dike

Question

Quizplus · Accepted Answer

The principle of crosscutting relationships states that a rock must first exist before it can be intruded by a dike. This principle applies in this situation because the igneous dike is younger than the rocks it intrudes upon, and its presence indicates that those older rocks must have existed first.

Which of the Following Geologic Principle Is Directly Applicable to an Igneous