Relative dating puts geologic events in chronological order without requiring that a specific numerical age be assigned to each event. Second, it is possible to determine the numerical age for fossils or earth materials.

Are inclusions older or younger?

Inclusions are always older than the rock they are found in. Even if we did not see the igneous and metamorphic rocks in surface exposures, the fact that they occur in the (brownish) sediment unit indicates the presence of older ingneous and metamoprhic rocks that supply material to that unit.