Radiometric dating calculates an age in years for geologic materials by measuring the presence of a short-life radioactive element, e. The term applies to all methods of age determination based on nuclear decay of naturally occurring radioactive isotopes. Bates and Jackson To determine the ages in years of Earth materials and the timing of geologic events such as exhumation and subduction, geologists utilize the process of radiometric decay. Geologists use these dates to further define the boundaries of the geologic periods shown on the geologic time scale. Radiometric decay occurs when the nucleus of a radioactive atom spontaneously transforms into an atomic nucleus of a different, more stable isotope.
Whenever the worldview of evolution is questioned, the topic of carbon dating always comes up. Here is how carbon dating works and the assumptions it is based upon. Radiation from the sun strikes the atmosphere of the earth all day long. This energy converts about 21 pounds of nitrogen into radioactive carbon This radioactive carbon 14 slowly decays back into normal, stable nitrogen. Extensive laboratory testing has shown that about half of the C molecules will decay in 5, years. This is called the half-life.
20.6: The Kinetics of Radioactive Decay and Radiometric Dating
The ease of using the formula for radioactive decay with common elements found in nature make it a powerful tool. Radiometric dating is the technique of using isotopic ratios of common elements to determine the age approximate of materials associated with the element, such as trees, rock strata, fossils, human artifacts and the like. Because radioactive decay follows a specific mathematical formula and is dependent upon unique decay rates half-lives of each element, formulas can be developed that compare the measured amounts of different elemental isotopes. The ratio of the difference is related mathematically to the time that is took for the original sample to decay into the ratios found.
Home earth Earth History Geologist Radioactive. Read about How do we know the Age of the Earth? Radiometric dating using the naturally-occurring radioactive elements is simple in concept even though technically complex. If we know the number of radioactive parent atoms present when a rock formed and the number present now, we can calculate the age of the rock using the decay constant.