The same thing can be done with geologic features in a rock outcrop.
To do this geologists use the Laws of Relative Dating.
Geologists use this type of method all the time to establish relative ages of rocks.
Now, what if instead of being horizontal, this rock layer was found in a tilted position?
It's called the Principle of Original Horizontality, and it just means what it sounds like: that all rock layers were originally horizontal. As you can imagine, regular sediments, like sand, silt, and clay, tend to accumulate over a wide area with a generally consistent thickness.
Numerical dating determines the actual ages of rocks through the study of radioactive decay.
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.
In order to establish relative dates, geologists must make an initial assumption about the way rock strata are formed. sediments, which are deposited and compacted in one place over time.
What could a geologist say about that section of rock?
Following the Principle of Original Horizontality, he could say that whatever forces caused the deformation, like an earthquake, must have occurred after the formation of all the rock strata.