The teacher should tell the students that there are two basic principles used by geologists to determine the sequence of ages of rocks. They are: Principle of superposition: Younger sedimentary rocks are deposited on top of older sedimentary rocks. Many rocks contain small amounts of unstable isotopes and the daughter isotopes into which they decay. U is found in most igneous rocks. They should write the ages of the pegmatite and granite beside the names of the rocks in the list below the block diagram Figure 1.
Which one of Dr. Pat Allen's dating classifications do you fall under?.