, , 8. Which is the youngest event? (a) The intrusion of rock layers (b) The formation of rock layers

To determine which event is the youngest between the intrusion of rock layers and the formation of rock layers, we can analyze the geological principles of relative dating, specifically the Law of Cross-Cutting Relationships.

1. Understanding the Events:

   • (a) The intrusion of rock layers involves molten rock (magma) forcing its way into existing formations and solidifying.
   • (b) The formation of rock layers refers to the process of sediment accumulation, compaction, and cementation over time.

2. Applying Geological Principles:

   • According to the Law of Cross-Cutting Relationships, an intrusive rock layer is considered younger than the layers it cuts through. This principle indicates that if an intrusion disrupts or passes through existing rock layers, the intrusion must have occurred after those layers were already formed.

3. Conclusion:

   • Based on this principle, the intrusion of rock layers (event a) is the youngest event because it represents a more recent geological process that occurs after the formation of the pre-existing rock layers (event b).

Final Answer

The youngest event is (a) The intrusion of rock layers.