Relative age dating geology
Using these techniques allows geologists to determine not only the relative age of rocks but fossils as well.The only way to determine the absolute age of a rock or fossil is by using absolute dating techniques which have to be performed in a lab.As a member, you'll also get unlimited access to over 79,000 lessons in math, English, science, history, and more.
The first is called absolute dating, where geologists use radioactive decay to determine the actual age of a rock. Let's say you are a geologist who is tasked with dating the rocks found in the Grand Canyon, and you must do so in the canyon without the aid of any laboratory equipment. Relative dating doesn't really give us an actual 'age,' but it does put things in sequential order.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?You can't make the cookie, then the chocolate chips, and then insert them into the cookie.So, basically it's the difference between saying 'I'm 25 years old, and my sibling is 20 years old' and 'I'm older than my sibling.' Geologists use a variety of techniques, or principles, to determine the relative age of a rock unit.Principle of original horizontality: This principle simply states that deposition of rocks occurs horizontally or nearly horizontally. Most deposition occurs as the ocean deposits sediment flat and horizontally on existing rock, either on the ocean floor or on the continent.