Question

If inclusions of rock C occur in rock B as shown in the image below, then?

1) rock C must be older than rock B
2) rock B must be older than rock C
3) rock B and rock C must be exactly the same age
4) rock B could be either older or younger than rock C

Answer 1

Rock C is older than rock B, based on the principle of inclusions, which dictates that an inclusion within a rock is older than the rock itself.

Step-by-step explanation:

If inclusions of rock C are present within rock B, according to the principle of inclusions developed by Charles Lyell, rock C must be older than rock B. This principle states that if one rock is contained within another, the rock that is included is older than the surrounding material. This can occur in different geological settings, such as when a mafic magma cools quickly to form mafic rock, and later on, due to changes in the magma's chemistry and cooling rate, the surrounding felsic rock forms.Based on this understanding of geological principles, the inclusions from rock C found in rock B suggest a sequence of events where rock C formed first, followed by rock B encapsulating it as it formed later on.Conclusion The main answer to the student's question is that rock C is older than rock B. This aligns with the developed principles of relative dating, specifically the principle of inclusions which implies that the inclusions predate the formation of the rock matrix they are found in.