Other techniques include analyzing amino acids and measuring changes in an object's magnetic field.
Scientists have also made improvements to the standard radiometric measurements.
Each of them typically exists in igneous rock, or rock made from cooled magma.
Fossils, however, form in sedimentary rock -- sediment quickly covers a dinosaur's body, and the sediment and the bones gradually turn into rock.
Dinosaur bones, on the other hand, are millions of years old -- some fossils are billions of years old.
To determine the ages of these specimens, scientists need an isotope with a very long half-life.
Strata systems are believed in some places to be inverted, repeated, or inserted where they do not belong.
Some of the isotopes used for this purpose are uranium-238, uranium-235 and potassium-40, each of which has a half-life of more than a million years.
Unfortunately, these elements don't exist in dinosaur fossils themselves.
Overturning, overthrust faulting, or landsliding are frequently maintained as disrupting the order.
In some locations such structural changes can be supported by physical evidence while elsewhere physical evidence of the disruption may be lacking and special pleading may be required using fossils or radiometric dating.