As more and more layers are deposited, the older rock layers end up at the bottom and the newer ones toward the top. What is the difference between relative and absolute age?
Prior to the discovery of radiometric dating which provided a means of absolute dating in the early 20th century, archaeologists and geologists used this technique to determine ages of materials.
Though relative dating can only determine the sequential order in which a series of events occurred, not when they occur, it remains a useful technique especially in radiometric dating.
Geologists draw on it and other basic principles ( to determine the relative ages of rocks or features such as faults.
Relative age dating also means paying attention to crosscutting relationships.
Current scientific evidence shows that the Earth is: c) more than 4 billion years old 2.
Look at the diagram below representing layers of rocks and the fossils buried in them. (The bottom layer is circled)b) Explain how you know which layer is the oldest.
There are two basic approaches: relative age dating, and absolute age dating.
Here is an easy-to understand analogy for your students: relative age dating is like saying that your grandfather is older than you.
The regular order of occurrence of fossils in rock layers was discovered around 1800 by William Smith.
You may not associate geology with time, but the former greatly depends on the latter.