<em><u>Absolute age is the age of a rock in years. Absolute age is found by measuring the amount of certain radioactive elements in the rock.</u></em>
During the formation of rock, small amounts of radioactive elements is normally included. As the time passes, the parent radioactive elements undergo decay at a regular rate into non-radioactive daughter elements.
<u><em>By measuring the rate at which a parent element decays and then the ratio of parent element to daughter element in the rock the age of rock in years can be found.</em></u>
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