Relative dating and radioactive dating
Dating is a technique used in archeology to ascertain the age of artifacts, fossils and other items considered to be valuable by archeologists.
There are many methods employed by these scientists, interested in the old, to get to know the age of items.
The atoms of some chemical elements have different forms, called isotopes.
These break down over time in a process scientists call radioactive decay.
All radiometric dating methods measure isotopes in some way.
Two broad categories of classification methods are relative dating and absolute dating.
For example, fission track dating measures the microscopic marks left in crystals by subatomic particles from decaying isotopes.
Another example is luminescence dating, which measures the energy from radioactive decay that is trapped inside nearby crystals.
When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.
Isotopes are important to geologists because each radioactive element decays at a constant rate, which is unique to that element.
However, age of deposition does not mean the age of artifacts found in that layer.