How do you determine the absolute age of a fossil?

Answer 1

How do you find a fossil's absolute age? The absolute age (or direct dating) of a fossil is determined by knowing the age of the surrounding rock. The most common way is by radiometric dating, a method that relies on the natural radioactivity of certain elemental isotopes. Different isotopic elements-such as uranium, rubidium, argon, and carbon-have varying (but constant) rates of radioactive decay. This constancy provides a "radiometric clock," allowing scientists to analyze rock samples and measure the relative ratios between the "parent" and "daughter" isotopes. The ratios reveal the age of the rock layer, and thus, the age of the associated fossil. As with many scientific measurements, although the method is called "absolute," the dates are not exact and there is room for potential errors.

Answer 2

By measuring the amount of Uranium contained within the specific rock/fossil. Uranium-238's Half-Life is about 4.47 billion years, So each 4.47 billion years, the amount of Uranium is reduced by half. If the accepted amount of Uranium for a time period is 25%, and the sample contains 12.5%, then it is twice as old as that time period. Scientists cannot use carbon dating on rocks because they were never living things, and did not inhale carbon-14 from the atmosphere.

Answer 3

You can only do this if it is possible to date the fossil by radiogenic means.