What is realative dating good for
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?
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.
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.
Your goal is to study the smooth, parallel layers of rock to learn how the land built up over geologic time.
Now imagine that you come upon a formation like this: What do you think of it? How can you make any conclusions about rock layers that make such a crazy arrangement?
Let's look at these rock strata here: We have five layers total.
Geologists establish the age of rocks in two ways: numerical dating and relative dating.
Numerical dating determines the actual ages of rocks through the study of radioactive decay.
There may be a layer missing in the strata, or a set of sedimentary rock on top of metamorphic rock.
These interfaces between discontinuous layers of rock are called unconformities.
These items are called inclusions - foreign bodies of rock or mineral enclosed within another rock.