How do you correlate rocks from one location to another using relative and radiometric (bracketing) techniques

Question

How do you correlate rocks from one location to another using relative and radiometric (bracketing) techniques

Answer 1

Most rocks are older as you go downward, although there are places where layers have been completely flipped.   Fossils follow a regular evolutionary progression and for example if you find trilobites in a rock layer you can be fairly confident of the age of the rock.    If you find dinosaur bones then it is older than 65 million years old.  Radiometric techniques depend on the relative decay of very slow-decaying elements trapped in rock.  Using the two together you can get an idea of both the absolute and relative age of rocks.