Definition relative dating biology
This allows geologists to determine the age of a rock or strata relative to another rock or strata.
So, instead of saying when something happened, it puts events in the order they happened.
In this example above, we have rock layers A - E and Fault F showing.
According to superposition, A is the oldest rock layer, while E is the youngest rock layer. According to cross-cutting relations, the fault is younger than those layers it cuts.
However, it does not cut layers D and E, so those layers are younger than Fault F.
Law of inclusions: This law states that when a rock contains pieces or fragments (also called inclusions) of another rock, these pieces or fragments must be older.
To think of it another way, the chocolate chips found in chocolate chip cookies must be made first before they are added to the cookie, right?
This can best be explained by looking at fossils embedded in a rock column.You can't start with the top layer and add the ones under it since there would be nothing to build on.