A fault (F) breaks three layers of sedimentary rock (S). An igneous intrusion (I1) has broken through the bottommost layer of rock. A second igneous intrusion (I2) has moved up the fault and pooled on top of the uppermost layer of rock. Which event would be considered the youngest?
The intrusion of I1 or I2 is the youngest event. Without more information, we cannot know which igneous rock is youngest.

The intrusion of I1 or I2 is the youngest event. Without more information, we cannot know which igneous rock is youngest.

Explanation:

The information contained in the question above is not sufficient to determine which of the two igneous rock intrusions is the youngest event, although we can say that it was one of the two.

Even in the absence of a complete answer, it is worth describing what an ignea rock is. Ignal rocks can also be called magmatic rocks and are characterized as a terrestrial rock that originated from the solidification of magma, without having previously undergone a process of sedimentation or metamorphism. As you may already know, magma can solidify and cool on the earth's surface, or inside the earth, giving rise to extrusive and intrusive igneous rocks.