Relative and absolute age dating
Let's say we find out, through numerical dating, that the rock layer shown above is 70 million years old.
Because the sedimentary rock had to have formed around the object for it to be encased within the layers, geologists can establish relative dates between the inclusions and the surrounding rock.
How do we use the Law of Superposition to establish relative dates?
Let's look at these rock strata here: We have five layers total.
There may be a layer missing in the strata, or a set of sedimentary rock on top of metamorphic rock.
These interfaces between discontinuous layers of rock are called unconformities.