Relative dating worksheet middle school classic dating site asia
Numerical dating determines the actual ages of rocks through the study of radioactive decay.
Relative dating cannot establish absolute age, but it can establish whether one rock is older or younger than another.
Relative dating requires an extensive knowledge of stratigraphic succession, a fancy term for the way rock strata are built up and changed by geologic processes.
In this lesson, we'll learn a few basic principles of stratigraphic succession and see whether we can find relative dates for those strange strata we found in the Grand Canyon.
Let's say, in this set of rock strata, that we found a single intrusion of igneous rock punching through the sedimentary layers.
The highest layers tell them what happened more recently, and the lowest layers tell them what happened longer ago.
How do we use the Law of Superposition to establish relative dates?
Learn how inclusions and unconformities can tell us stories about the geologic past.
We'll even visit the Grand Canyon to solve the mystery of the Great Unconformity!We could assume that this igneous intrusion must have happened after the formation of the strata.If it had happened before the layers had formed, then we wouldn't see it punching through all the layers; we would only see it going through the layers that had existed at the time that it happened. The Principle of Cross-Cutting Relationships states that rock formations that cut across other rocks must be younger than the rocks that they cut across.We're not so sure about the next layer down, but the one below it is 100 million years old. Not exactly, but we do know that it's somewhere between 70 and 100 million years old.